This book was sent to me by Matt Schoeneberger, who co-authored it with Jeff Thiboutot. Both have master's degrees in exercise science and health promotion. S.P.E.E.D. stands for Sleep, Psychology, Exercise, Environment and Diet. The authors have attempted to create a concise, comprehensive weight loss strategy based on what they feel is the most compelling scientific evidence available. It's subtitled "The Only Weight Loss Book Worth Reading". Despite the subtitle that's impossible to live up to, it was an interesting and well-researched book. It was a very fast read at 205 large-print pages including 32 pages of appendices and index.
I really appreciate the abundant in-text references the authors provided. I have a hard time taking a health and nutrition book seriously that doesn't provide any basis to evaluate its statements. There are already way too many people flapping their lips out there, without providing any outside support for their statements, for me to tolerate that sort of thing. Even well-referenced books can be a pain if the references aren't in the text itself. Schoeneberger and Thiboutot provided appropriate, accessible references for nearly every major statement in the book.
Chapter one, "What is a Healthy Weight", discusses the evidence for an association between body weight and health. They note that both underweight and obesity are associated with poor health outcomes, whereas moderate overweight isn't. While I agree, I continue to maintain that being fairly lean and appropriately muscled (which doesn't necessarily mean muscular) is probably optimal. The reason that people with a body mass index (BMI) considered to be "ideal" aren't healthier on average than people who are moderately overweight may have to do with the fact that many people with an "ideal" BMI are skinny-fat, i.e. have low muscle mass and too much abdominal fat.
Chapter 2, "Sleep", discusses the importance of sleep in weight regulation and overall health. They reference some good studies and I think they make a compelling case that it's important. Chapter 3, "Psychology", details psychological strategies to motivate and plan for effective weight loss.
Chapter 4, "Exercise", provides an exercise plan for weight loss. The main message: do it! I think they give a fair overview of the different categories of exercise and their relative merits, including high-intensity intermittent training (HIIT). However, the exercise regimen they suggest is intense and will probably lead to overtraining in many people. They recommend resistance training major, multi-joint exercises, 1-3 sets to muscular failure 2-4 days a week. I've been at the higher end of that recommendation and it made my joints hurt, plus I was weaker than when I strength trained less frequently. I think the lower end of their recommendation, 1 set of each exercise to failure twice a week, is more than sufficient to meet the goal of maximizing improvements in body composition in most people. My current routine is one brief strength training session and one sprint session per week (in addition to my leisurely cycle commute), which works well for me on a cost-benefit level. However, I was stronger when I was strength training twice a week and never going to muscular failure (a la Pavel Tsatsouline).
Chapter 5, "Environment", is an interesting discussion of different factors that promote excessive calorie intake, such as the setting of the meal, the company or lack thereof, and food presentation. While they support their statements very well with evidence from scientific studies, I do have a lingering doubt about these types of studies: as far as I know, they're all based on short-term interventions. Science would be a lot easier if short-term always translated to long term, but unfortunately that's not the case. For example, studies lasting one or two weeks show that low glycemic index foods cause a reduction in calorie intake and greater feelings of fullness. However, this effect disappears in the long term, and numerous controlled trials show that low glycemic index diets have no effect on food intake, body weight or insulin sensitivity in the long term. I reviewed those studies here.
The body has homeostatic mechanisms (homeostatic = maintains the status quo) that regulate long-term energy balance. Whether short-term changes in calorie intake based on environmental cues would translate into sustained changes that would have a significant impact on body fat, I don't know. For example, if you eat a meal with your extended family at a restaurant that serves massive portions, you might eat twice as much as you would by yourself in your own home. But the question is, will your body factor that huge meal into your subsequent calorie intake and energy expenditure over the following days? The answer is clearly yes, but the degree of compensation is unclear. Since I'm not aware of any trials indicating that changing meal context can actually lead to long-term weight loss, I can't put much faith in this strategy (if you know otherwise, please link to the study in the comments).
Chapter 6, "Diet", is a very brief discussion of what to eat for weight loss. They basically recommend a low-calorie, low-carb diet focused on whole, natural foods. I think low-carbohydrate diets can be useful for some overweight people trying to lose weight, if for no other reason than the fact that they make it easier to control appetite. In addition, a subset of people respond very well to carbohydrate restriction in terms of body composition, health and well-being. The authors emphasize nutrient density, but don't really explain how to achieve it. It would have been nice to see a discussion of a few topics such as organ meats, leafy greens, dairy quality (pastured vs. conventional) and vitamin D. These may not help you lose weight, but they will help keep you healthy, particularly on a calorie-restricted diet. The authors also recommend a few energy bars, powders and supplements that I don't support. They state that they have no financial connection to the manufacturers of the products they recommend.
I'm wary of their recommendation to deliberately restrict calorie intake. Although it will clearly cause fat loss if you restrict calories enough, it's been shown to be ineffective for sustainable, long-term fat loss over and over again. The only exception is the rare person with an iron will who is able to withstand misery indefinitely. I'm going to keep an open mind on this question though. There may be a place for deliberate calorie restriction in the right context. But at this point I'm going to require some pretty solid evidence that it's effective, sustainable, and doesn't have unacceptable side effects.
The book contains a nice bonus, an appendix titled "What is Quality Evidence"? It's a brief discussion of common logical pitfalls when evaluating evidence, and I think many people could benefit from reading it.
Overall, S.P.E.E.D. was a worthwhile read, definitely superior to 95% of fat loss books. With some caveats mentioned above, I think it could be a useful resource for someone interested in fat loss.
Tuesday, May 25, 2010
Monday, May 24, 2010
Thank You
I'd like to extend my sincere thanks to everyone who has supported me through donations this year. The money has allowed me to buy materials that I wouldn't otherwise have been able to afford, and I feel it has enriched the blog for everyone. Here are some of the books I've bought using donations. Some were quite expensive:
Food and western disease: health and nutrition from an evolutionary perspective. Staffan Lindeberg (just released!!)
Nutrition and disease. Edward Mellanby
Migration and health in a small society: the case of Tokelau. Edited by Albert F. Wessen
The saccharine disease. T. L. Cleave
Culture, ecology and dental anthropology. John R. Lukacs
Vitamin K in health and disease. John W. Suttie
Craniofacial development. Geoffrey H. Sperber
Western diseases: their emergence and prevention. Hugh C. Trowell and Denis P. Burkitt
The ultimate omega-3 diet. Evelyn Tribole
Our changing fare. John Yudkin and colleagues
Donations have also paid for many, many photocopies at the medical library. I'd also like to thank everyone who participates in the community by leaving comments, or by linking to my posts. I appreciate your encouragement, and also the learning opportunities.
Food and western disease: health and nutrition from an evolutionary perspective. Staffan Lindeberg (just released!!)
Nutrition and disease. Edward Mellanby
Migration and health in a small society: the case of Tokelau. Edited by Albert F. Wessen
The saccharine disease. T. L. Cleave
Culture, ecology and dental anthropology. John R. Lukacs
Vitamin K in health and disease. John W. Suttie
Craniofacial development. Geoffrey H. Sperber
Western diseases: their emergence and prevention. Hugh C. Trowell and Denis P. Burkitt
The ultimate omega-3 diet. Evelyn Tribole
Our changing fare. John Yudkin and colleagues
Donations have also paid for many, many photocopies at the medical library. I'd also like to thank everyone who participates in the community by leaving comments, or by linking to my posts. I appreciate your encouragement, and also the learning opportunities.
Magnesium and Insulin Sensitivity
From a paper based on US NHANES nutrition and health survey data (1):
Magnesium status is associated with insulin sensitivity (2, 3), and a low magnesium intake predicts the development of type II diabetes in most studies (4, 5) but not all (6). Magnesium supplements largely prevent diabetes in a rat model* (7). Interestingly, excess blood glucose and insulin themselves seem to reduce magnesium status, possibly creating a vicious cycle.
In a 1993 trial, a low-magnesium diet reduced insulin sensitivity in healthy volunteers by 25% in just four weeks (8). It also increased urinary thromboxane concentration, a potential concern for cardiovascular health**.
At least three trials have shown that magnesium supplementation increases insulin sensitivity in insulin-resistant diabetics and non-diabetics (9, 10, 11). In some cases, the results were remarkable. In type II diabetics, 16 weeks of magnesium supplementation improved fasting glucose, calculated insulin sensitivity and HbA1c*** (12). HbA1c dropped by 22 percent.
In insulin resistant volunteers with low blood magnesium, magnesium supplementation for four months reduced estimated insulin resistance by 43 percent and decreased fasting insulin by 32 percent (13). This suggests to me that magnesium deficiency was probably one of the main reasons they were insulin resistant in the first place. But the study had another very interesting finding: magnesium improved the subjects' blood lipid profile remarkably. Total cholesterol decreased, LDL decreased, HDL increased and triglycerides decreased by a whopping 39 percent. The same thing had been reported in the medical literature decades earlier when doctors used magnesium injections to treat heart disease, and also in animals treated with magnesium. Magnesium supplementation also suppresses atherosclerosis (thickening and hardening of the arteries) in animal models, a fact that I may discuss in more detail at some point (14, 15).
In the previous study, participants were given 2.5 g magnesium chloride (MgCl2) per day. That's a bit more than the USDA recommended daily allowance (MgCl2 is mostly chloride by weight), in addition to what they were already getting from their diet. Most of a person's magnesium is in their bones, so correcting a deficiency by eating a nutritious diet may take a while.
Speaking of nutritious diets, how does one get magnesium? Good sources include halibut, leafy greens, chocolate and nuts. Bone broths are also an excellent source of highly absorbable magnesium. Whole grains and beans are also fairly good sources, while refined grains lack most of the magnesium in the whole grain. Organic foods, particularly artisanally produced foods from a farmer's market, are richer in magnesium because they grow on better soil and often use older varieties that are more nutritious.
The problem with seeds such as grains, beans and nuts is that they also contain phytic acid which prevents the absorption of magnesium and other minerals (16). Healthy non-industrial societies that relied on grains took great care in their preparation: they soaked them, often fermented them, and also frequently removed a portion of the bran before cooking (17). These steps all served to reduce the level of phytic acid and other anti-nutrients. I've posted a method for effectively reducing the amount of phytic acid in brown rice (18). Beans should ideally be soaked for 24 hours before cooking, preferably in warm water.
Industrial agriculture has systematically depleted our soil of many minerals, due to high-yield crop varieties and the fact that synthetic fertilizers only replace a few minerals. The mineral content of foods in the US, including magnesium, has dropped sharply in the last 50 years. The reason we need to use fertilizers in the first place is that we've broken the natural nutrient cycle in which minerals always return to the soil in the same place they were removed. In 21st century America, minerals are removed from the soil, pass through our toilets, and end up in the landfill or in waste water. This will continue until we find an acceptable way to return human feces and urine to agricultural soil, as many cultures do to this day****.
I believe that an adequate magnesium intake is critical for proper insulin sensitivity and overall health.
* Zucker rats that lack leptin signaling
** Thromboxane A2 is an omega-6 derived eicosanoid that potently constricts blood vessels and promotes blood clotting. It's interesting that magnesium has such a strong effect on it. It indicates that fatty acid balance is not the only major influence on eicosanoid production.
*** Glycated hemoglobin. A measure of the average blood glucose level over the past few weeks.
**** Anyone interested in further reading on this should look up The Humanure Handbook
During 1999–2000, the diet of a large proportion of the U.S. population did not contain adequate magnesium... Furthermore, racial or ethnic differences in magnesium persist and may contribute to some health disparities.... Because magnesium intake is low among many people in the United States and inadequate magnesium status is associated with increased risk of acute and chronic conditions, an urgent need exists to perform a current survey to assess the physiologic status of magnesium in the U.S. population.Magnesium is an essential mineral that's slowly disappearing from the modern diet, as industrial agriculture and industrial food processing increasingly dominate our food choices. One of the many things it's necessary for in mammals is proper insulin sensitivity and glucose control. A loss of glucose control due to insulin resistance can eventually lead to diabetes and all its complications.
Magnesium status is associated with insulin sensitivity (2, 3), and a low magnesium intake predicts the development of type II diabetes in most studies (4, 5) but not all (6). Magnesium supplements largely prevent diabetes in a rat model* (7). Interestingly, excess blood glucose and insulin themselves seem to reduce magnesium status, possibly creating a vicious cycle.
In a 1993 trial, a low-magnesium diet reduced insulin sensitivity in healthy volunteers by 25% in just four weeks (8). It also increased urinary thromboxane concentration, a potential concern for cardiovascular health**.
At least three trials have shown that magnesium supplementation increases insulin sensitivity in insulin-resistant diabetics and non-diabetics (9, 10, 11). In some cases, the results were remarkable. In type II diabetics, 16 weeks of magnesium supplementation improved fasting glucose, calculated insulin sensitivity and HbA1c*** (12). HbA1c dropped by 22 percent.
In insulin resistant volunteers with low blood magnesium, magnesium supplementation for four months reduced estimated insulin resistance by 43 percent and decreased fasting insulin by 32 percent (13). This suggests to me that magnesium deficiency was probably one of the main reasons they were insulin resistant in the first place. But the study had another very interesting finding: magnesium improved the subjects' blood lipid profile remarkably. Total cholesterol decreased, LDL decreased, HDL increased and triglycerides decreased by a whopping 39 percent. The same thing had been reported in the medical literature decades earlier when doctors used magnesium injections to treat heart disease, and also in animals treated with magnesium. Magnesium supplementation also suppresses atherosclerosis (thickening and hardening of the arteries) in animal models, a fact that I may discuss in more detail at some point (14, 15).
In the previous study, participants were given 2.5 g magnesium chloride (MgCl2) per day. That's a bit more than the USDA recommended daily allowance (MgCl2 is mostly chloride by weight), in addition to what they were already getting from their diet. Most of a person's magnesium is in their bones, so correcting a deficiency by eating a nutritious diet may take a while.
Speaking of nutritious diets, how does one get magnesium? Good sources include halibut, leafy greens, chocolate and nuts. Bone broths are also an excellent source of highly absorbable magnesium. Whole grains and beans are also fairly good sources, while refined grains lack most of the magnesium in the whole grain. Organic foods, particularly artisanally produced foods from a farmer's market, are richer in magnesium because they grow on better soil and often use older varieties that are more nutritious.
The problem with seeds such as grains, beans and nuts is that they also contain phytic acid which prevents the absorption of magnesium and other minerals (16). Healthy non-industrial societies that relied on grains took great care in their preparation: they soaked them, often fermented them, and also frequently removed a portion of the bran before cooking (17). These steps all served to reduce the level of phytic acid and other anti-nutrients. I've posted a method for effectively reducing the amount of phytic acid in brown rice (18). Beans should ideally be soaked for 24 hours before cooking, preferably in warm water.
Industrial agriculture has systematically depleted our soil of many minerals, due to high-yield crop varieties and the fact that synthetic fertilizers only replace a few minerals. The mineral content of foods in the US, including magnesium, has dropped sharply in the last 50 years. The reason we need to use fertilizers in the first place is that we've broken the natural nutrient cycle in which minerals always return to the soil in the same place they were removed. In 21st century America, minerals are removed from the soil, pass through our toilets, and end up in the landfill or in waste water. This will continue until we find an acceptable way to return human feces and urine to agricultural soil, as many cultures do to this day****.
I believe that an adequate magnesium intake is critical for proper insulin sensitivity and overall health.
* Zucker rats that lack leptin signaling
** Thromboxane A2 is an omega-6 derived eicosanoid that potently constricts blood vessels and promotes blood clotting. It's interesting that magnesium has such a strong effect on it. It indicates that fatty acid balance is not the only major influence on eicosanoid production.
*** Glycated hemoglobin. A measure of the average blood glucose level over the past few weeks.
**** Anyone interested in further reading on this should look up The Humanure Handbook
How to Review Your Homeowners Insurance Renewal Statement
For most of us, our home is our single largest and most important investment. Many of us have poured thousands of dollars and countless hours into maintaining, improving and (hopefully) paying off our homes. Many people own their homes free of any mortgage. These assets are pure equity. Certainly its worthwhile to invest 15 minutes a year to be sure it's properly insured.
Thankfully, the insurance company offers you a perfect reminder and opportunity in sending out your annual renewal statement. Even if your insurance is paid by your mortgage company as part of your impound account, the insurance company still mails you a statement of renewal every year to update you with your current coverage limits and deductible.
Here's a few important steps you can take to be sure that HOME SWEET HOME is properly protected.
1. Check the basics. Check your name, address and any other description of the insured property. Make sure there's been no change of vesting or ownership that needs to be updated. Check your address to be sure no numbers are transposed.
2. Check the mortgagee clause. Here's where you can be sure that the current mortagee on your home is listed correctly. Check the lender, address and your loan number. Be sure there's no old information there. Maybe you had a HELOC (Home Equity Line of Credit) or a second mortgage that no longer applies. Be sure to get them removed.
Thankfully, the insurance company offers you a perfect reminder and opportunity in sending out your annual renewal statement. Even if your insurance is paid by your mortgage company as part of your impound account, the insurance company still mails you a statement of renewal every year to update you with your current coverage limits and deductible.
Here's a few important steps you can take to be sure that HOME SWEET HOME is properly protected.
1. Check the basics. Check your name, address and any other description of the insured property. Make sure there's been no change of vesting or ownership that needs to be updated. Check your address to be sure no numbers are transposed.
2. Check the mortgagee clause. Here's where you can be sure that the current mortagee on your home is listed correctly. Check the lender, address and your loan number. Be sure there's no old information there. Maybe you had a HELOC (Home Equity Line of Credit) or a second mortgage that no longer applies. Be sure to get them removed.
HEADS UP: Whenever you have a significant claim, the mortgage company will be one of the payees on your claim settlement check. Just that alone can be an inconvenience. But it becomes a major hassle when one of the institutions listed no longer has a vested interest in your home. The insurance company is bound by contract to include the mortgage company on all settlement checks beyond a stated threshold.
*3. Check the coverage on your home (dwelling or building). This is without question the single most important coverage to examine, consider and adjust whenever necessary. Having been an agent during the two raging firestorms in San Diego, CA in this decade, I can tell you that underinsured homes are just NO FUN! Two of my clients lost their homes in the 2003 fires and fortunately they were both adequately insured. (we call all our homeowner clients once a year to review their coverages and suggest improvements and adjustments) But I can tell you that there were literally hundreds of people in the area that were not so fortunate. Many were underinsured by over $100,000! Contractors were giving rebuilding bids on homes for $400,000 with insurance policies with limits less than $300,000. See if that doesn't tweak your financial well-being just a little. Here's the solution.Get an accurate rendering of the square footage of your home. Check county records, take a look at zillow.com, call your favorite Realtor, or get a tape measure and do your thing. Usually you don't include the garage in this calculation. Once you get your square footage, then you need to determine the building cost per square foot in your area for a home like yours. Call a local contractor for a quick estimate or you can call your insurance agent. Average costs in San Diego run about $200 per square foot. With that, a 2000 square foot would take about $400,000 to rebuild. Custom homes can be significantlly more. For a more complete discussion of this, check out: How Much Homeowners Insurance Do You REALLY Need?
Your contents coverage is usually 75% of the amount you have on your home. For example, if you have $400,000 on your home, you'll have an additional $300,000 to cover your personal property (furniture, clothing, dishes, TV, collections, shoes, tools, etc) Usually this is enough, but think through it anyway. If you have antiques, art, collections of any kind then you may need more. Ask your agent for help if you need to.
4. Look at your Personal Liability Coverage. This is the coverage you need when you get sued. Little Johnny runs across your front yard and trips on one of your sprinklers and ruins his chances to become America's Next Top Model and his parents sue your for $250,000. Make sure you don't scrimp here. It's not too expensive to get $500,000 or even $1 Million of liability coverage. If you have $100,000 or less, you could be setting yourself up for a mess just waiting to happen. Put a really big checkbook between your assets and someone who sees an injury as a lifetime paycheck. You might even consider a Liability Umbrella.
5. Check your 'special limits'. This is a REALLY BROAD subject that I just can't do justice to here in this post. Simply stated, there's limits on many things such as cash, computers, cameras, jewelry, furs, goldware, silverware, tools, etc. Call your company and ask for a review. You can increase many of these limits for just a few dollars a year. Sometimes the available increase isn't enough. That's the perfect time to consider a Personal Articles Floater (or it's called many different names) It's a policy that's designed to place stated amounts of coverage on many items from jewelry, business tools, iPods, hearing aids, cameras, musical instruments and on and on. If you have more than 'the average Joe' of ANYTHING, then check this out FOR SURE!
6. Check your deductible! This can be a tremendous cost-control tool in your insurance spending. Simply stated: The larger your deductible, the greater your savings. Usually you can save close to $100 per year just by going from a $500 deductible to $1000. Pick the largest number you can stand without losing sleep at night and ask your agent or company the savings you'd realize by changing. If you have a $250 or smaller deductible, it's definitely time to change it UP! Keep in mind that you usually hit a point of 'diminishing returns' once you get to $4000 or more. This means that you'll save less and less for each additional $1000 you choose. It might make sense to go from $1000 to $2000 if you save $85 a year by doing so, but not from $5000 to $6000 if you only save another $21 by making that jump.
Monitoring your insurance costs and coverages can result in a lot of savings AND peace of mind. Be sure you keep notes and file your thoughts and changes from year to year. These recoreds will make your annual call quicker and easier each year.
Feel free to contact me anytime if you have questions.
Till next time...
phil heath Kai Greene Branch Warren after the 2009 Mr Olympia video phil heath met rx
phil heath
video of phil heath Kai Greene and Branch Warren after the 2009 Mr Olympia, phil heath was unlucky at the 2009 mr olympia due to some illness going into the mr olympia bodybuilding contest.
but aspect to see phil heath pushing for the 2010 mr olympia title and in much better condition then the 2009 mr olympia contest.
phil heath is wearing a met rx t-shirt in the video not sure if phil heath is still sponsored by met rx or not now.
Dissolve Away those Pesky Bones with Corn Oil
I just read an interesting paper from Gabriel Fernandes's group at the University of Texas. It's titled "High fat diet-induced animal model of age-associated obesity and osteoporosis". I was expecting this to be the usual "we fed mice industrial lard for 60% of calories and they got sick" paper, but I was pleasantly surprised. From the introduction:
20% fat is less than the amount it typically takes to make a rodent this sick. This leads me to conclude that corn oil is particularly good at causing mouse versions of some of the most common facets of the "diseases of civilization". It's exceptionally high in omega-6 (linoleic acid) with virtually no omega-3.
Make sure to eat your heart-healthy corn oil! It's made in the USA, dirt cheap and it even lowers cholesterol!
CO [corn oil] is known to promote bone loss, obesity, impaired glucose tolerance, insulin resistance and thus represents a useful model for studying the early stages in the development of obesity, hyperglycemia, Type 2 diabetes [23] and osteoporosis. We have used omega-6 fatty acids enriched diet as a fat source which is commonly observed in today's Western diets basically responsible for the pathogenesis of many diseases [24].Just 10% of the diet as corn oil (roughly 20% of calories), with no added omega-3, on top of an otherwise poor laboratory diet, caused:
- Obesity
- Osteoporosis
- The replacement of bone marrow with fat cells
- Diabetes
- Insulin resistance
- Generalized inflammation
- Elevated liver weight (possibly indicating fatty liver)
20% fat is less than the amount it typically takes to make a rodent this sick. This leads me to conclude that corn oil is particularly good at causing mouse versions of some of the most common facets of the "diseases of civilization". It's exceptionally high in omega-6 (linoleic acid) with virtually no omega-3.
Make sure to eat your heart-healthy corn oil! It's made in the USA, dirt cheap and it even lowers cholesterol!
Lindeberg on Obesity
I'm currently reading Dr. Staffan Lindeberg's magnum opus Food and Western Disease, recently published in English for the first time. Dr. Lindeberg is one of the world's leading experts on the health and diet of non-industrial cultures, particularly in Papua New Guinea. The book contains 2,034 references. It's also full of quotable statements. Here's what he has to say about obesity:
I'd recommend this book to anyone who has a scholarly interest in health and nutrition, and somewhat of a background in science and medicine. It's extremely well referenced, which makes it much more valuable.
Middle-age spread is a normal phenomenon - assuming you live in the West. Few people are able to maintain their [youthful] waistline after age 50. The usual explanation - too little exercise and too much food - does not fully take into account the situation among traditional populations. Such people are usually not as physically active as you may think, and they usually eat large quantities of food.The only obese Kitavans Dr. Lindeberg observed were two people who had spent several years off the island living a modern, urban lifestyle, and were back on Kitava for a visit.
Overweight has been extremely rare among hunter-gatherers and other traditional cultures [18 references]. This simple fact has been quickly apparent to all foreign visitors...
The Kitava study measured height, weight, waist circumference, subcutaneous fat thickness at the back of the upper arm (triceps skinfold) and upper arm circumference on 272 persons ages 4-86 years. Overweight and obesity were absent and average [body mass index] was low across all age groups. ...no one was larger around their waist than around their hips.
...The circumference of the upper arm [mostly indicating muscle mass] was only negligibly smaller on Kitava [compared with Sweden], which indicates that there was no malnutrition. It is obvious from our investigations that lack of food is an unknown concept, and that the surplus of fruits and vegetables regularly rots or is eaten by dogs.
The Population of Kitava occupies a unique position in the world in terms of the negligible effect that the Western lifestyle has had on the island.
I'd recommend this book to anyone who has a scholarly interest in health and nutrition, and somewhat of a background in science and medicine. It's extremely well referenced, which makes it much more valuable.
Sunday, May 23, 2010
The Body Fat Setpoint, Part IV: Changing the Setpoint
Prevention is Easier than Cure
Experiments in animals have confirmed what common sense suggests: it's easier to prevent health problems than to reverse them. Still, many health conditions can be improved, and in some cases reversed, through lifestyle interventions. It's important to have realistic expectations and to be kind to oneself. Cultivating a drill sergeant mentality will not improve quality of life, and isn't likely to be sustainable.
Fat Loss: a New Approach
If there's one thing that's consistent in the medical literature, it's that telling people to eat fewer calories does not help them lose weight in the long term. Gary Taubes has written about this at length in his book Good Calories, Bad Calories, and in his upcoming book on body fat. Many people who use this strategy see transient fat loss, followed by fat regain and a feeling of defeat. There's a simple reason for it: the body doesn't want to lose weight. It's extremely difficult to fight the fat mass setpoint, and the body will use every tool it has to maintain its preferred level of fat: hunger, reduced body temperature, higher muscle efficiency (i.e., less energy is expended for the same movement), lethargy, lowered immune function, et cetera.
Therefore, what we need for sustainable fat loss is not starvation; we need a treatment that lowers the fat mass setpoint. There are several criteria that this treatment will have to meet to qualify:
Strategies: Diet Pattern
The most obvious treatment that fits all of my criteria is low-carbohydrate dieting. Overweight people eating low-carbohydrate diets generally lose fat and spontaneously reduce their calorie intake. In fact, in several diet studies, investigators compared an all-you-can-eat low-carbohydrate diet with a calorie-restricted low-fat diet. The low-carbohydrate dieters generally reduced their calorie intake and body fat to a similar or greater degree than the low-fat dieters, despite the fact that they ate all the calories they wanted (1). This suggest that their fat mass setpoint had changed. At this point, I think moderate carbohydrate restriction may be preferable to strict carbohydrate restriction for some people, due to the increasing number of reports I've read of people doing poorly in the long run on extremely low-carbohydrate diets (2).
Another strategy that appears effective is the "paleolithic" diet. In Dr. Staffan Lindeberg's 2007 diet study, overweight volunteers with heart disease lost fat and reduced their calorie intake to a remarkable degree while eating a diet consistent with our hunter-gatherer heritage (3). This result is consistent with another diet trial of the paleolithic diet in diabetics (4). In post hoc analysis, Dr. Lindeberg's group showed that the reduction in weight was apparently independent of changes in carbohydrate intake*. This suggests that the paleolithic diet has health benefits that are independent of carbohydrate intake.
Strategies: Gastrointestinal Health
Since the gastrointestinal (GI) tract is so intimately involved in body fat metabolism and overall health (see the former post), the next strategy is to improve GI health. There are a number of ways to do this, but they all center around four things:
Oligofructose is similar to inulin, a fiber that occurs naturally in a wide variety of plants. Good sources are jerusalem artichokes, jicama, artichokes, onions, leeks, burdock and chicory root. Certain non-industrial cultures had a high intake of inulin. There are some caveats to inulin, however: inulin and oligofructose can cause gas, and can also exacerbate gastroesophageal reflux disorder (9). So don't eat a big plate of jerusalem artichokes before that important date.
The colon is packed with symbiotic bacteria, and is the site of most intestinal fermentation. The small intestine contains fewer bacteria, but gut barrier function there is critical as well. The small intestine is where the GI doctor will take a biopsy to look for celiac disease. Celiac disease is a degeneration of the small intestinal lining due to an autoimmune reaction caused by gluten (in wheat, barley and rye). This brings us to one of the most important elements of maintaining gut barrier health: avoiding food sensitivities. Gluten and casein (in dairy protein) are the two most common offenders. Gluten sensitivity is widespread and typically undiagnosed (10).
Eating raw fermented foods such as sauerkraut, kimchi, yogurt and half-sour pickles also helps maintain the integrity of the upper GI tract. I doubt these have any effect on the colon, given the huge number of bacteria already present. Other important factors in gut barrier health are keeping the ratio of omega-6 to omega-3 fats in balance, eating nutrient-dense food, and avoiding the questionable chemical additives in processed food. If triglycerides are important for leptin sensitivity, then avoiding sugar and ensuring a regular source of omega-3 should aid weight loss as well.
Strategies: Micronutrients
As I discussed in the last post, micronutrient deficiency probably plays a role in obesity, both in ways that we understand and ways that we (or I) don't. Eating a diet that has a high nutrient density and ensuring a good vitamin D status will help any sustainable fat loss strategy. The easiest way to do this is to eliminate industrially processed foods such as white flour, sugar and seed oils. These constitute more than 50% of calories for the average Westerner.
After that, you can further increase your diet's nutrient density by learning to properly prepare grains and legumes to maximize their nutritional value and digestibility (11, 12; or by avoiding grains and legumes altogether if you wish), selecting organic and/or pasture-raised foods if possible, and eating seafood including seaweed. One of the problems with extremely low-carbohydrate diets is that they may be low in water-soluble micronutrients, although this isn't necessarily the case.
Strategies: Miscellaneous
In general, exercise isn't necessarily helpful for fat loss. However, there is one type of exercise that clearly is: high-intensity intermittent training (HIIT). It's basically a fancy name for sprints. They can be done on a track, on a stationary bicycle, using weight training circuits, or any other way that allows sufficient intensity. The key is to achieve maximal exertion for several brief periods, separated by rest. This type of exercise is not about burning calories through exertion: it's about increasing hormone sensitivity using an intense, brief stressor (hormesis). Even a ridiculously short period of time spent training HIIT each week can result in significant fat loss, despite no change in diet or calorie intake (13).
Anecdotally, many people have had success using intermittent fasting (IF) for fat loss. There's some evidence in the scientific literature that IF and related approaches may be helpful (14). There are different approaches to IF, but a common and effective method is to do two complete 24-hour fasts per week. It's important to note that IF isn't about restricting calories, it's about resetting the fat mass setpoint. After a fast, allow yourself to eat quality food until you're no longer hungry.
Insufficient sleep has been strongly and repeatedly linked to obesity. Whether it's a cause or consequence of obesity I can't say for sure, but in any case it's important for health to sleep until you feel rested. If your sleep quality is poor due to psychological stress, meditating before bedtime may help. I find that meditation has a remarkable effect on my sleep quality. Due to the poor development of oral and nasal structures in industrial nations, many people do not breathe effectively and may suffer from conditions such as sleep apnea that reduce sleep quality. Overweight also contributes to these problems.
I'm sure there are other useful strategies, but that's all I have for now. If you have something to add, please put it in the comments.
* Since reducing carbohydrate intake wasn't part of the intervention, this result is observational.
Experiments in animals have confirmed what common sense suggests: it's easier to prevent health problems than to reverse them. Still, many health conditions can be improved, and in some cases reversed, through lifestyle interventions. It's important to have realistic expectations and to be kind to oneself. Cultivating a drill sergeant mentality will not improve quality of life, and isn't likely to be sustainable.
Fat Loss: a New Approach
If there's one thing that's consistent in the medical literature, it's that telling people to eat fewer calories does not help them lose weight in the long term. Gary Taubes has written about this at length in his book Good Calories, Bad Calories, and in his upcoming book on body fat. Many people who use this strategy see transient fat loss, followed by fat regain and a feeling of defeat. There's a simple reason for it: the body doesn't want to lose weight. It's extremely difficult to fight the fat mass setpoint, and the body will use every tool it has to maintain its preferred level of fat: hunger, reduced body temperature, higher muscle efficiency (i.e., less energy is expended for the same movement), lethargy, lowered immune function, et cetera.
Therefore, what we need for sustainable fat loss is not starvation; we need a treatment that lowers the fat mass setpoint. There are several criteria that this treatment will have to meet to qualify:
- It must cause fat loss
- It must not involve deliberate calorie restriction
- It must maintain fat loss over a long period of time
- It must not be harmful to overall health
Strategies: Diet Pattern
The most obvious treatment that fits all of my criteria is low-carbohydrate dieting. Overweight people eating low-carbohydrate diets generally lose fat and spontaneously reduce their calorie intake. In fact, in several diet studies, investigators compared an all-you-can-eat low-carbohydrate diet with a calorie-restricted low-fat diet. The low-carbohydrate dieters generally reduced their calorie intake and body fat to a similar or greater degree than the low-fat dieters, despite the fact that they ate all the calories they wanted (1). This suggest that their fat mass setpoint had changed. At this point, I think moderate carbohydrate restriction may be preferable to strict carbohydrate restriction for some people, due to the increasing number of reports I've read of people doing poorly in the long run on extremely low-carbohydrate diets (2).
Another strategy that appears effective is the "paleolithic" diet. In Dr. Staffan Lindeberg's 2007 diet study, overweight volunteers with heart disease lost fat and reduced their calorie intake to a remarkable degree while eating a diet consistent with our hunter-gatherer heritage (3). This result is consistent with another diet trial of the paleolithic diet in diabetics (4). In post hoc analysis, Dr. Lindeberg's group showed that the reduction in weight was apparently independent of changes in carbohydrate intake*. This suggests that the paleolithic diet has health benefits that are independent of carbohydrate intake.
Strategies: Gastrointestinal Health
Since the gastrointestinal (GI) tract is so intimately involved in body fat metabolism and overall health (see the former post), the next strategy is to improve GI health. There are a number of ways to do this, but they all center around four things:
- Don't eat food that encourages the growth of harmful bacteria
- Eat food that encourages the growth of good bacteria
- Don't eat food that impairs gut barrier function
- Eat food that promotes gut barrier health
Oligofructose is similar to inulin, a fiber that occurs naturally in a wide variety of plants. Good sources are jerusalem artichokes, jicama, artichokes, onions, leeks, burdock and chicory root. Certain non-industrial cultures had a high intake of inulin. There are some caveats to inulin, however: inulin and oligofructose can cause gas, and can also exacerbate gastroesophageal reflux disorder (9). So don't eat a big plate of jerusalem artichokes before that important date.
The colon is packed with symbiotic bacteria, and is the site of most intestinal fermentation. The small intestine contains fewer bacteria, but gut barrier function there is critical as well. The small intestine is where the GI doctor will take a biopsy to look for celiac disease. Celiac disease is a degeneration of the small intestinal lining due to an autoimmune reaction caused by gluten (in wheat, barley and rye). This brings us to one of the most important elements of maintaining gut barrier health: avoiding food sensitivities. Gluten and casein (in dairy protein) are the two most common offenders. Gluten sensitivity is widespread and typically undiagnosed (10).
Eating raw fermented foods such as sauerkraut, kimchi, yogurt and half-sour pickles also helps maintain the integrity of the upper GI tract. I doubt these have any effect on the colon, given the huge number of bacteria already present. Other important factors in gut barrier health are keeping the ratio of omega-6 to omega-3 fats in balance, eating nutrient-dense food, and avoiding the questionable chemical additives in processed food. If triglycerides are important for leptin sensitivity, then avoiding sugar and ensuring a regular source of omega-3 should aid weight loss as well.
Strategies: Micronutrients
As I discussed in the last post, micronutrient deficiency probably plays a role in obesity, both in ways that we understand and ways that we (or I) don't. Eating a diet that has a high nutrient density and ensuring a good vitamin D status will help any sustainable fat loss strategy. The easiest way to do this is to eliminate industrially processed foods such as white flour, sugar and seed oils. These constitute more than 50% of calories for the average Westerner.
After that, you can further increase your diet's nutrient density by learning to properly prepare grains and legumes to maximize their nutritional value and digestibility (11, 12; or by avoiding grains and legumes altogether if you wish), selecting organic and/or pasture-raised foods if possible, and eating seafood including seaweed. One of the problems with extremely low-carbohydrate diets is that they may be low in water-soluble micronutrients, although this isn't necessarily the case.
Strategies: Miscellaneous
In general, exercise isn't necessarily helpful for fat loss. However, there is one type of exercise that clearly is: high-intensity intermittent training (HIIT). It's basically a fancy name for sprints. They can be done on a track, on a stationary bicycle, using weight training circuits, or any other way that allows sufficient intensity. The key is to achieve maximal exertion for several brief periods, separated by rest. This type of exercise is not about burning calories through exertion: it's about increasing hormone sensitivity using an intense, brief stressor (hormesis). Even a ridiculously short period of time spent training HIIT each week can result in significant fat loss, despite no change in diet or calorie intake (13).
Anecdotally, many people have had success using intermittent fasting (IF) for fat loss. There's some evidence in the scientific literature that IF and related approaches may be helpful (14). There are different approaches to IF, but a common and effective method is to do two complete 24-hour fasts per week. It's important to note that IF isn't about restricting calories, it's about resetting the fat mass setpoint. After a fast, allow yourself to eat quality food until you're no longer hungry.
Insufficient sleep has been strongly and repeatedly linked to obesity. Whether it's a cause or consequence of obesity I can't say for sure, but in any case it's important for health to sleep until you feel rested. If your sleep quality is poor due to psychological stress, meditating before bedtime may help. I find that meditation has a remarkable effect on my sleep quality. Due to the poor development of oral and nasal structures in industrial nations, many people do not breathe effectively and may suffer from conditions such as sleep apnea that reduce sleep quality. Overweight also contributes to these problems.
I'm sure there are other useful strategies, but that's all I have for now. If you have something to add, please put it in the comments.
* Since reducing carbohydrate intake wasn't part of the intervention, this result is observational.
Saturated Fat and Insulin Sensitivity
Insulin sensitivity is a measure of the tissue response to insulin. Typically, it refers to insulin's ability to cause tissues to absorb glucose from the blood. A loss of insulin sensitivity, also called insulin resistance, is a core part of the metabolic disorder that affects many people in industrial nations.
I don't know how many times I've seen the claim in journal articles and on the internet that saturated fat reduces insulin sensitivity. The idea is that saturated fat reduces the body's ability to handle glucose effectively, placing people on the road to diabetes, obesity and heart disease. Given the "selective citation disorder" that plagues the diet-health literature, perhaps this particular claim deserves a closer look.
The Evidence
I found a review article from 2008 that addressed this question (1). I like this review because it only includes high-quality trials that used reliable methods of determining insulin sensitivity*.
On to the meat of it. There were 5 studies in which non-diabetic people were fed diets rich in saturated fat, and compared with a group eating a diet rich in monounsaturated (like olive oil) or polyunsaturated (like corn oil) fat. They ranged in duration from one week to 3 months. Four of the five studies found that fat quality did not affect insulin sensitivity, including one of the 3-month studies.
The fifth study, which is the one that's nearly always cited in the diet-health literature, requires some discussion. This was the KANWU study (2). Over the course of three months, investigators fed 163 volunteers a diet rich in either saturated fat or monounsaturated fat.
What the authors decided to focus on instead is the fact that insulin sensitivity declined slightly but significantly on the saturated fat diet compared with the pre-diet baseline. That's why this study is cited as evidence that saturated fat impairs insulin sensitivity. But anyone who has a basic science background will see where this reasoning is flawed (warning: nerd attack. skip the rest of the paragraph if you're not interested). You need a control group for comparison, to take into account normal fluctuations caused by such things as the season, eating mostly cafeteria food, and having a doctor hooking you up to machines. That control group was the group eating monounsaturated fat. The comparison between diet groups was the 'primary outcome', in statistics lingo. That's the comparison that matters, and it wasn't significant. To interpret the study otherwise is to ignore the basic conventions of statistics, which the authors were happy to do. There's a name for it: 'moving the goalpost'. The reviewers shouldn't have let this kind of shenanigans slide.
So we have five studies through 2008, none of which support the idea that saturated fat reduces insulin sensitivity in non-diabetics. Since the review paper was published, I know of one subsequent study that asked the same question (3). Susan J. van Dijk and colleagues fed volunteers with abdominal overweight (beer gut) a diet rich in either saturated fat or monounsaturated fat. I e-mailed the senior author and she said the saturated fat diet was "mostly butter". The specific fats used in the diets weren't mentioned anywhere in the paper, which is a major omission**. In any case, after 8 weeks, insulin sensitivity was virtually identical between the two groups. This study appeared well controlled and used the gold standard method for assessing insulin sensitivity, called the euglycemic-hyperinsulinemic clamp technique***.
The evidence from controlled trials is rather consistent that saturated fat has no appreciable effect on insulin sensitivity.
Why Are We so Focused on Saturated Fat?
Answer: because it's the nutrient everyone loves to hate. As an exercise in completeness, I'm going to mention three dietary factors that actually reduce insulin sensitivity, and get a lot less air time than saturated fat.
#1: Caffeine. That's right, controlled trials show that your favorite murky beverage reduces insulin sensitivity (4, 5). Is it actually relevant to real life? I doubt it. The doses used were large and the studies short-term.
#2: Magnesium deficiency. A low-magnesium diet reduced insulin sensitivity by 25% over the course of three weeks (6). I think this is probably relevant to long-term insulin sensitivity and overall health, although it would be good to have longer-term data. Magnesium deficiency is widespread in industrial nations, due to our over-reliance on refined foods such as sugar, white flour and oils.
#3: Sugar. Fructose reduces insulin sensitivity in humans, along with many other harmful effects (7).
As long as we continue to focus our energy on indicting saturated fat, it will continue distracting us from the real causes of disease.
* For the nerds: euglycemic-hyperinsulinemic clamp (the gold standard), insulin suppression test, or intravenous glucose tolerance test with Minimal Model. They didn't include studies that reported HOMA as their only measure, because it's not very accurate.
** There's this idea that pervades the diet-health literature that all saturated fats are roughly equivalent, all monounsaturated fats are equivalent, etc., therefore it doesn't matter what the source was. This is beyond absurd and reflects our cultural obsession with saturated fat. It really irks me that the reviewers didn't demand this information.
*** They did find that markers of inflammation in fat tissue were higher after the saturated fat diet.
I don't know how many times I've seen the claim in journal articles and on the internet that saturated fat reduces insulin sensitivity. The idea is that saturated fat reduces the body's ability to handle glucose effectively, placing people on the road to diabetes, obesity and heart disease. Given the "selective citation disorder" that plagues the diet-health literature, perhaps this particular claim deserves a closer look.
The Evidence
I found a review article from 2008 that addressed this question (1). I like this review because it only includes high-quality trials that used reliable methods of determining insulin sensitivity*.
On to the meat of it. There were 5 studies in which non-diabetic people were fed diets rich in saturated fat, and compared with a group eating a diet rich in monounsaturated (like olive oil) or polyunsaturated (like corn oil) fat. They ranged in duration from one week to 3 months. Four of the five studies found that fat quality did not affect insulin sensitivity, including one of the 3-month studies.
The fifth study, which is the one that's nearly always cited in the diet-health literature, requires some discussion. This was the KANWU study (2). Over the course of three months, investigators fed 163 volunteers a diet rich in either saturated fat or monounsaturated fat.
The SAFA diet included butter and a table margarine containing a relatively high proportion of SAFAs. The MUFA diet included a spread and a margarine containing high proportions of oleic acid derived from high-oleic sunflower oil and negligible amounts of trans fatty acids and n-3 fatty acids and olive oil.Yummy. After three months of these diets, there was no significant difference in insulin sensitivity between the saturated fat group and the monounsaturated fat group. Yes, you read that right. Even the study that's selectively cited as evidence that saturated fat causes insulin resistance found no significant difference between the diets. You might not get this by reading the misleading abstract. I'll be generous and acknowledge that the (small) difference was almost statistically significant (p = 0.053).
What the authors decided to focus on instead is the fact that insulin sensitivity declined slightly but significantly on the saturated fat diet compared with the pre-diet baseline. That's why this study is cited as evidence that saturated fat impairs insulin sensitivity. But anyone who has a basic science background will see where this reasoning is flawed (warning: nerd attack. skip the rest of the paragraph if you're not interested). You need a control group for comparison, to take into account normal fluctuations caused by such things as the season, eating mostly cafeteria food, and having a doctor hooking you up to machines. That control group was the group eating monounsaturated fat. The comparison between diet groups was the 'primary outcome', in statistics lingo. That's the comparison that matters, and it wasn't significant. To interpret the study otherwise is to ignore the basic conventions of statistics, which the authors were happy to do. There's a name for it: 'moving the goalpost'. The reviewers shouldn't have let this kind of shenanigans slide.
So we have five studies through 2008, none of which support the idea that saturated fat reduces insulin sensitivity in non-diabetics. Since the review paper was published, I know of one subsequent study that asked the same question (3). Susan J. van Dijk and colleagues fed volunteers with abdominal overweight (beer gut) a diet rich in either saturated fat or monounsaturated fat. I e-mailed the senior author and she said the saturated fat diet was "mostly butter". The specific fats used in the diets weren't mentioned anywhere in the paper, which is a major omission**. In any case, after 8 weeks, insulin sensitivity was virtually identical between the two groups. This study appeared well controlled and used the gold standard method for assessing insulin sensitivity, called the euglycemic-hyperinsulinemic clamp technique***.
The evidence from controlled trials is rather consistent that saturated fat has no appreciable effect on insulin sensitivity.
Why Are We so Focused on Saturated Fat?
Answer: because it's the nutrient everyone loves to hate. As an exercise in completeness, I'm going to mention three dietary factors that actually reduce insulin sensitivity, and get a lot less air time than saturated fat.
#1: Caffeine. That's right, controlled trials show that your favorite murky beverage reduces insulin sensitivity (4, 5). Is it actually relevant to real life? I doubt it. The doses used were large and the studies short-term.
#2: Magnesium deficiency. A low-magnesium diet reduced insulin sensitivity by 25% over the course of three weeks (6). I think this is probably relevant to long-term insulin sensitivity and overall health, although it would be good to have longer-term data. Magnesium deficiency is widespread in industrial nations, due to our over-reliance on refined foods such as sugar, white flour and oils.
#3: Sugar. Fructose reduces insulin sensitivity in humans, along with many other harmful effects (7).
As long as we continue to focus our energy on indicting saturated fat, it will continue distracting us from the real causes of disease.
* For the nerds: euglycemic-hyperinsulinemic clamp (the gold standard), insulin suppression test, or intravenous glucose tolerance test with Minimal Model. They didn't include studies that reported HOMA as their only measure, because it's not very accurate.
** There's this idea that pervades the diet-health literature that all saturated fats are roughly equivalent, all monounsaturated fats are equivalent, etc., therefore it doesn't matter what the source was. This is beyond absurd and reflects our cultural obsession with saturated fat. It really irks me that the reviewers didn't demand this information.
*** They did find that markers of inflammation in fat tissue were higher after the saturated fat diet.
New Saturated Fat Review Article by Dr. Ronald Krauss
I never thought I'd see the day when one of the most prominent lipid researchers in the world did an honest review of the observational studies evaluating the link between saturated fat and cardiovascular disease. Dr. Ronald Krauss's group has published a review article titled "Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease". As anyone with two eyes and access to the medical literature would conclude (including myself), they found no association whatsoever between saturated fat intake and heart disease or stroke:
Thanks to Peter for pointing out this article.
A meta-analysis of prospective epidemiologic studies showed that there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD or CVD.Bravo, Dr. Krauss. That was a brave move.
Thanks to Peter for pointing out this article.
Phil heath youtube video - "Phil heath is my dad :D (joke)".
new Phil heath youtube video, well kind of, just found this video on youtube of a amateur odybuilder posing, video title says "Phil heath is my dad :D", i think the poser is meaning in relation to him having such good genetics, and muscle shape like phil heath.
though the guys shape also has a look of dexter jackson as well.
can the real phil heath stand up, phil heath arms, phil being known for some of the biggest arms in bodybuilding:
going to be looking at the phil heath diet and phil heath workout in some upcoming posts as well.
though the guys shape also has a look of dexter jackson as well.
can the real phil heath stand up, phil heath arms, phil being known for some of the biggest arms in bodybuilding:
going to be looking at the phil heath diet and phil heath workout in some upcoming posts as well.
Saturday, May 22, 2010
Paleo is Going Mainstream
There was an article on the modern "Paleolithic" lifestyle in the New York Times today. I thought it was a pretty fair treatment of the subject, although it did paint it as more macho and carnivorous than it needs to be. It features three attractive NY cave people. It appeared in the styles section here. Paleo is going mainstream. We can expect media health authorities to start getting defensive about it any minute now.
The Body Fat Setpoint, Part II: Mechanisms of Fat Gain
The Timeline of Fat Gain
Modern humans are unusual mammals in that fat mass varies greatly between individuals. Some animals carry a large amount of fat for a specific purpose, such as hibernation or migration. But all individuals of the same sex and social position will carry approximately the same amount of fat at any given time of year. Likewise, in hunter-gatherer societies worldwide, there isn't much variation in body weight-- nearly everyone is lean. Not necessarily lean like Usain Bolt, but not overweight.
Although overweight and obesity occurred forty years ago in the U.S. and U.K., they were much less common than today, particularly in children. Here are data from the U.S. Centers for Disease Control NHANES surveys (from this post):
Together, this shows that a) leanness is the most natural condition for the human body, and b) something about our changing environment, not our genes, has caused our body fat to grow.
Fat Mass is Regulated by a Feedback Circuit Between Fat Tissue and the Brain
In the last post, I described how the body regulates fat mass, attempting to keep it within a narrow window or "setpoint". Body fat produces a hormone called leptin, which signals to the brain and other organs to decrease appetite, increase the metabolic rate and increase physical activity. More fat means more leptin, which then causes the extra fat to be burned. The little glitch is that some people become resistant to leptin, so that their brain doesn't hear the fat tissue screaming that it's already full. Leptin resistance nearly always accompanies obesity, because it's a precondition of significant fat gain. If a person weren't leptin resistant, he wouldn't have the ability to gain more than a few pounds of fat without heroic overeating (which is very very unpleasant when your brain is telling you to stop). Animal models of leptin resistance develop something that resembles human metabolic syndrome (abdominal obesity, blood lipid abnormalities, insulin resistance, high blood pressure).
The Role of the Hypothalamus
The hypothalamus is on the underside of the brain connected to the pituitary gland. It's the main site of leptin action in the brain, and it controls the majority of leptin's effects on appetite, energy expenditure and insulin sensitivity. Most of the known gene variations that are associated with overweight in humans influence the function of the hypothalamus in some way (1). Not surprisingly, leptin resistance in the hypothalamus has been proposed as a cause of obesity. It's been shown in rats and mice that hypothalamic leptin resistance occurs in diet-induced obesity, and it's almost certainly the case in humans as well. What's causing leptin resistance in the hypothalamus?
There are three leading explanations at this point that are not mutually exclusive. One is cellular stress in the endoplasmic reticulum, a structure inside the cell that's used for protein synthesis and folding. I've read the most recent paper on this in detail, and I found it unconvincing (2). I'm open to the idea, but it needs more rigorous support.
A second explanation is inflammation in the hypothalamus. Inflammation inhibits leptin and insulin signaling in a variety of cell types. At least two studies have shown that diet-induced obesity in rodents leads to inflammation in the hypothalamus (3, 4)*. If leptin is getting to the hypothalamus, but the hypothalamus is insensitive to it, it will require more leptin to get the same signal, and fat mass will creep up until it reaches a higher setpoint.
The other possibility is that leptin simply isn't reaching the hypothalamus. The brain is a unique organ. It's enclosed by the blood-brain barrier (BBB), which greatly restricts what can enter and leave it. Both insulin and leptin are actively transported across the BBB. It's been known for a decade that obesity in rodents is associated with a lower rate of leptin transport across the BBB (5, 6).
What causes a decrease in leptin transport across the BBB? Triglycerides are a major factor. These are circulating fats going from the liver and the digestive tract to other tissues. They're one of the blood lipid measurements the doctor makes when he draws your blood. Several studies in rodents have shown that high triglycerides cause a reduction in leptin transport across the BBB, and reducing triglycerides allows greater leptin transport and fat loss (7, 8). In support of this theory, the triglyceride-reducing drug gemfibrozil also causes weight loss in humans (9)**. Guess what else reduces triglycerides and causes weight loss? Low-carbohydrate diets, and avoiding sugar and refined carbohydrates in particular.
In the next post, I'll get more specific about what factors could be causing hypothalamic inflammation and/or reduced leptin transport across the BBB. I'll also discuss some ideas on how to reduce leptin resistance sustainably through diet and exercise.
* This is accomplished by feeding them sad little pellets that look like greasy chalk. They're made up mostly of lard, soybean oil, casein, maltodextrin or cornstarch, sugar, vitamins and minerals (this is a link to the the most commonly used diet for inducing obesity in rodents). Food doesn't get any more refined than this stuff, and adding just about anything to it, from fiber to fruit extracts, makes it less damaging.
** Fibrates are PPAR agonists, so the weight loss could also be due to something besides the reduction in triglycerides.
Modern humans are unusual mammals in that fat mass varies greatly between individuals. Some animals carry a large amount of fat for a specific purpose, such as hibernation or migration. But all individuals of the same sex and social position will carry approximately the same amount of fat at any given time of year. Likewise, in hunter-gatherer societies worldwide, there isn't much variation in body weight-- nearly everyone is lean. Not necessarily lean like Usain Bolt, but not overweight.
Although overweight and obesity occurred forty years ago in the U.S. and U.K., they were much less common than today, particularly in children. Here are data from the U.S. Centers for Disease Control NHANES surveys (from this post):
Together, this shows that a) leanness is the most natural condition for the human body, and b) something about our changing environment, not our genes, has caused our body fat to grow.Fat Mass is Regulated by a Feedback Circuit Between Fat Tissue and the Brain
In the last post, I described how the body regulates fat mass, attempting to keep it within a narrow window or "setpoint". Body fat produces a hormone called leptin, which signals to the brain and other organs to decrease appetite, increase the metabolic rate and increase physical activity. More fat means more leptin, which then causes the extra fat to be burned. The little glitch is that some people become resistant to leptin, so that their brain doesn't hear the fat tissue screaming that it's already full. Leptin resistance nearly always accompanies obesity, because it's a precondition of significant fat gain. If a person weren't leptin resistant, he wouldn't have the ability to gain more than a few pounds of fat without heroic overeating (which is very very unpleasant when your brain is telling you to stop). Animal models of leptin resistance develop something that resembles human metabolic syndrome (abdominal obesity, blood lipid abnormalities, insulin resistance, high blood pressure).
The Role of the Hypothalamus
The hypothalamus is on the underside of the brain connected to the pituitary gland. It's the main site of leptin action in the brain, and it controls the majority of leptin's effects on appetite, energy expenditure and insulin sensitivity. Most of the known gene variations that are associated with overweight in humans influence the function of the hypothalamus in some way (1). Not surprisingly, leptin resistance in the hypothalamus has been proposed as a cause of obesity. It's been shown in rats and mice that hypothalamic leptin resistance occurs in diet-induced obesity, and it's almost certainly the case in humans as well. What's causing leptin resistance in the hypothalamus?
There are three leading explanations at this point that are not mutually exclusive. One is cellular stress in the endoplasmic reticulum, a structure inside the cell that's used for protein synthesis and folding. I've read the most recent paper on this in detail, and I found it unconvincing (2). I'm open to the idea, but it needs more rigorous support.
A second explanation is inflammation in the hypothalamus. Inflammation inhibits leptin and insulin signaling in a variety of cell types. At least two studies have shown that diet-induced obesity in rodents leads to inflammation in the hypothalamus (3, 4)*. If leptin is getting to the hypothalamus, but the hypothalamus is insensitive to it, it will require more leptin to get the same signal, and fat mass will creep up until it reaches a higher setpoint.
The other possibility is that leptin simply isn't reaching the hypothalamus. The brain is a unique organ. It's enclosed by the blood-brain barrier (BBB), which greatly restricts what can enter and leave it. Both insulin and leptin are actively transported across the BBB. It's been known for a decade that obesity in rodents is associated with a lower rate of leptin transport across the BBB (5, 6).
What causes a decrease in leptin transport across the BBB? Triglycerides are a major factor. These are circulating fats going from the liver and the digestive tract to other tissues. They're one of the blood lipid measurements the doctor makes when he draws your blood. Several studies in rodents have shown that high triglycerides cause a reduction in leptin transport across the BBB, and reducing triglycerides allows greater leptin transport and fat loss (7, 8). In support of this theory, the triglyceride-reducing drug gemfibrozil also causes weight loss in humans (9)**. Guess what else reduces triglycerides and causes weight loss? Low-carbohydrate diets, and avoiding sugar and refined carbohydrates in particular.
In the next post, I'll get more specific about what factors could be causing hypothalamic inflammation and/or reduced leptin transport across the BBB. I'll also discuss some ideas on how to reduce leptin resistance sustainably through diet and exercise.
* This is accomplished by feeding them sad little pellets that look like greasy chalk. They're made up mostly of lard, soybean oil, casein, maltodextrin or cornstarch, sugar, vitamins and minerals (this is a link to the the most commonly used diet for inducing obesity in rodents). Food doesn't get any more refined than this stuff, and adding just about anything to it, from fiber to fruit extracts, makes it less damaging.
** Fibrates are PPAR agonists, so the weight loss could also be due to something besides the reduction in triglycerides.
Krauss's New Article on Saturated Fat Intervention Trials
Dr. Ronald Krauss's group just published another article in the American Journal of Clinical Nutrition, this time on the intervention trials examining the effectiveness of reducing saturated fat and/or replacing it with other nutrients, particularly carbohydrate or polyunsaturated seed oils. I don't agree with everything in this article. For example, they cite the Finnish Mental Hospital trial. They openly acknowledge some contradictory data, although they left out the Sydney diet-heart study and the Rose et al. corn oil study, both of which showed greatly increased mortality from replacing animal fats with polyunsaturated seed oils. Nevertheless, they get it right in the end:
Particularly given the differential effects of dietary saturated fats and carbohydrates on concentrations of larger and smaller LDL particles, respectively, dietary efforts to improve the increasing burden of CVD risk associated with atherogenic dyslipidemia should primarily emphasize the limitation of refined carbohydrate intakes and a reduction in excess adiposity.This is really cool. Krauss is channeling Weston Price. If this keeps up, I may have no reason to blog anymore!
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