My colleague, Dr Peter Attia, has written a thoughtful response to this question on his blog:
Dr Andreas Eenfeldt has chimed in, as well at:
Both offer good explanations. It’s good to understand this phenomenon because you will encounter this question from believers and non-believers alike.
The easy answer is that we are actually mischaracterizing their high carb diets. To understand, we first have to look at our high carb diet. The carbs contained in ours are mostly refined. This means an extensive industry. Their high carb diet is not supported by the same industry. Rather, since they have no industry that can produce anywhere near the same quantity of refined carbs, the total carb content of their diet is much lower than what we’d like to believe. And since they have no extensive industry, this means the refined carbs that they do eat cost a whole lot more than ours to produce, therefore constitute a much smaller part of their total carb intake. Think diseases of the rich.
As we eat more carbs, we eat less fat. When we look at low carb studies, two things are obvious. Those who do best eat less carbs, and eat more fat. While some would like to believe that most of the fat in these healthy diets are olive oil and such, the truth is that olive also requires an extensive industry. The more accessible fats are animal fats such as lard and cream for example. So they eat less total carbs, less refined carbs, and more animal fats.
Gary Taubes had already explained another aspect. He said that the carbs in those healthy diets are whole, unrefined. Since humans can’t digest plant fiber, and since those carbs are contained within those fibers, humans don’t actually absorb them and so do not suffer their effect.
Dr William Davis offers another explanation in Wheat Belly. He makes a strong point that modern dwarf wheat is uniquely obesogenic. If that’s true, then that’s another reason why traditional diets are healthy – they don’t contain any of that modern dwarf wheat. Modern dwarf wheat also needs an extensive industry incidentally..
So basically, the reason they stay lean is that we mischarazterize their high carb diet because we ignore the extensive industry needed to supply the amount of carbs in our diet. In other words, they stay lean because they don’t actually eat a high carb diet.
It should be noted that there is a huge difference between not getting fat in the first place, and reducing excess body fat. Observations about people who were always slim may not be helpful to infer what must be done to reduce fat.
It seems to me that carbohydrate tolerance is a useful concept to analyze the problem. From what I have read and deduced, there are a lot of factors that affect carbohydrate tolerance. Basically, the question is how much, when and what types of carbohydrate can be ingested before the liver is outpaced by the influx of carbs. Carb tolerance will be higher when glycogen levels are low–more room to absorb. Carb tolerance will increase with exercise after eating, so muscles take up and burn sugar, lessening the rise in blood sugar. Timothy Ferriss (The Four-Hour Body) recommends doing some intense pre-meal and post-meal exercises (for higher carbohydrate meals) to enhance the GLUT-4 transport system that transfer sugar from blood into muscle cells. A Chinese saying is that a person who climbs 100 steps after every meal lives to 99. Romans would walk 5 Roman miles (for about an hour) after a big meal to aid the liver. Recent research shows significant benefits of stand-up desks, which enable office workers to keep blood sugar levels lower, exercising the leg muscles continuously (as opposed to sitting). Put simply, these practices enhance carbohydrate tolerance, especially as blood sugar rises after a carbohydrate-laden meal..
Eating probiotics introduces carb-eating bacteria into the gut, which reduces the amount ingested, and so increase carbohydrate tolerance. Eating cinnamon evidently increases insulin sensitivity, to enhance the capacity of cells to remove sugar from blood, thus increasing carbohydrate tolerance. eating fat with carbohydrates slows ingestion into the blood.
All of these practices reduce the burden on the liver, which otherwise has to convert sugar into triglyceride fats and make cholesterol and VLDL particles to ferry the carb-sourced fat to fat cells (mostly around the belly). If the liver falls even further behind, fat accumulates in the liver. Many of the diseases of Western civilization are diseases of chronically exceeding carbohydrate tolerance.
Higher carb cultures have learned techniques and use portion control to stay within carb tolerance. There is a danger in eclectically picking and varying foods and practices from different cultures out of the entire cultural context, especially from cultural groups that have a different genetic heritage. It seems most venerable cultures evolved a suite of culture-specific methods of staying within carbohydrate tolerance. Modern nutritionists have provided little (if any) useful guidance in this respect.
Good points, Martin. (You posted while I was drafting my earlier post.) I should have mentioned that food preparation techniques affect carbohydrate tolerance. Refinement of foods increases the speed and quantity of the uptake of carbohydrates into the blood and the rate of carbohydrate burden on the liver–carbohydrate tolerance is increased with less refinement or cooking. Richard Wrangham’s book on the advent of cooking (Caching Fire) is interesting on how grinding and cooking of foods enhances the caloric uptake.
Thanks, Murray. You made some good points too. I especially like the point about getting fat in the first place and having to get lean afterward. It’s a whole nother ball game.
I’d like to address one point you made – genetics. I agree with you. Picking and choose individual aspects of various diets will get us nowhere. But when looking at them globally, we can understand better. For this, we have to look at the work of Weston Price. To summarize, while no two diets are exactly the same, we can still see a common factor – they all lack refined carbs, and they all contain animal fats. Though Price himself concluded differently. As Price observed, all populations who switched to modern diets promptly developed the same diseases as the rest of us. This means that even if they are genetically different, those differences do not affect their vulnerability to our modern diet. All of this further confirms the idea that we are really mischaracterizing their diets.
It just occurred to me that we also mischaracterize our own diet. How often do you hear somebody ask their butcher “don’t trim”? You know what I mean “don’t trim the fat off”. It is so uncommon that the first time I asked my butcher he said “but I always trim”. It took me about two weeks to convince him that I really truly wanted him to keep the fat on and sell me that fat meat. And that it was for me, not for my dog or cat. And even for their dog, they still ask to trim. The low fat dogma is as strong as ever and it shows its effect on our perspective of traditional diets.
Martin, I did not mean to suggest genetics would make anyone immune from ill-effects of high consumption of refined starches and sugar. Tolerances vary, but eventually everyone has a maximum tolerance.
I read an report on an interesting study a couple of years ago that had identified over 500 genetic variations that have arisen in the past 10,000, such as lactose tolerance. (Of course, these are not universal among all people.) The report noted several that increased tolerance for grain and reduced risk of diabetes. So longstanding grain cultures likely have some adaptations to increase tolerance, but the ultra-refinement and quantities of today have apparently outpaced even those variations.
Here is a quote from the report in ScienceNow:
“Although the researchers don’t know the function of most of the 582 genes that were under such intense positive natural selection, they have identified about 50 that appear to be responses to diseases or changes in diet or environment. Some examples include mutations that alter how adults regulate insulin, digest sugars and starches, metabolize ethanol and zinc, transport fats, regulate the immune response to pathogens, and repair and replicate DNA. “New mutations that ‘protect’ people from diabetes and obesity have been selected probably because they significantly improved peoples’ ability to handle agricultural diets,” says biological anthropologist John Hawks of the University of Wisconsin, Madison, who collaborates with Harpending. For example, he says, new dependence on a few cereal grains required efficient digestion of starches.”
ScienceNOW Daily News
4 February 2008
Dr. Jay. My virus program blocked a threat from your blog called “Blackhole”.
And, from a family member in Korea: they eat white rice in huge amounts, with fatty meat, sweet/sour pickled vegetables and sweetened sauces. You don’t get to choose whether you put them on or not. The people are very thin, and usually only eat one meal a day. No one cooks at home because they are all at work and then study both adults and children at night and on Saturdays and Sundays. The pace of living is frenetic, much more than we associate with big city living here or the U.S.
That is, the MEAT they eat is fatty, but they eat primarily fish, seafood and tofu, then meat.
@Murray, it sounds good but I see a problem. It’s based on the idea of positive selection pressure. The way I see it, natural selection works on negative pressure only. To understand, we have to establish three types of genes. The beneficial, the detrimental, the neutral. And also the idea that any gene can be any of those depending on conditions.
For example, the amylase gene can be both beneficial and detrimental depending on the quantity and frequency of starch intake. But it becomes neutral when we rely on mostly meat as our source of food. We have like 14 copies of the amylase gene. It’s useless when we eat mostly meat, but it’s not detrimental either so there’s no negative pressure to eliminate it. Where the selective pressure does occur is with the inability to eat mostly meat. This gene will disappear. So we’re left with humans who can eat meat, with multiple copies of the neutral amylase gene.
Take the cheetah for example. Here, the detrimental gene would be the “slow” gene. A neutral gene would be the “yellow/black fur” gene. We’re left with extremely fast, yellow/black cheetahs. We could also see it as strong/weak genetic selection. The strong genetic selection occurs with speed, the weak genetic selection occurs with fur color. But always negative selection, never positive.
Another way of looking at it is that natural selection sieves from the bottom. Those unable to deal with the current conditions don’t survive. Those able to deal with non-current conditions can still survive, and reproduce those currently-useless abilities. This explains in part the huge variation in forms of life. In other words, all species are experts at survival because all species have had their detrimental genes removed through negative selective pressure. But all species are wildly different because none have had their neutral genes removed.
For lactose tolerance, some have it, some don’t. Yet all can eat meat. If a condition arises where we have the choice to eat meat and survive only a short time, or drink milk and survive longer (especially early in life), then that’s another negative pressure to eliminate those without the ability to digest lactose. Though lactose intolerance might be related to gluten sensitivity whereby gluten triggers it. And this would muddy the waters with respect to natural selection of lactose tolerance.
I’m being lengthy and repetitive, sorry.
… and then there is sexual selection. Zahavi’s handicap principle could be a factor. I can imagine teenage males engaging is destructive peer-driven behaviour (binges of smoking, drugs, alcohol, french fries, coca cola, rough sports) to provide an honest signal of genetic fitness (tolerance to sustain a handicap). The males who break out in zits and get fat from carbs (i.e., have less genetic adaptation to handle an agricultural diet) fare poorly on the dating market. Just a 1% advantage would make a large difference over several generations.
I enjoyed the documentary on your Alert Bay experiment and have found your Blog quite interesting, Dr. Jay.
In your original outline of the project you said: ” When the data collection is complete we will do the usual statistical analyses and write a paper to be submitted for publication in a scientific journal.” I see a visitor subsequently posed a question about this and you indicated publication was still going too happen. I may have missed it but I still haven’t seen your study published. I’m wondering if you could explain where things stand today, and outline why this interesting work hasn’t been published yet?
Also on the subject of studies, it’s not uncommon to see industry-funded studies designed to drive market share or preserve status quo. The tobacco, sugar and pharmaceutical industries come to mind. What can you tell us about foods on the “wrong side,” of the carb debate? Are you aware for example, of a significant response to the margarine manufacturers’ campaign against butter, or of anything from the red meat sector? What could or should these groups be doing to further research like yours?
How many Canadian MDs would you estimate are supportive of “the alternative theory?”
Dr Jay’s Reply:
Yes, we have struggled to get a manuscript finished. I had a conversation with Dr Eric Westman about this just a couple of days ago in Denver where we were attending the Nutrition and Metabolism annual scientific meeting. The results were good and consistent with what others have reported. In general, if people were compliant with the diet they did well. There were some problems with the data that were not related to the diet that we have been trying to overcome. I expect we will eventually submit a manuscript, maybe sooner rather than later, now.
I am not aware of direct industry sponsored research that goes against low-carb. I think they work in a more roundabout way. The researchers develop cosy relationships with industry and then conduct research that supports the status quo. All the conflicting studies about sugar come to mind. Not all of them are sponsored by industry but the researchers have other, less direct, ties to the companies that benefit from the findings. On a bad day, I tend to think the whole game is rigged from top to bottom by industry involvement in universities, non-governmental organizations, governments and policy-setting and professional bodies. This pervasive influence definitely determines what gets done and who gets the grant money to do it. On top of that, the business of setting research priorities and directing research funding is exquisitely designed to protect the status quo. It is very hard to get funded if your hypothesis challenges the conventional wisdom.
People like me and my colleagues should be finding natural allies in the food sectors that are consistent with a low-carb high-fat diet. However, my attempts to make those connections, so far, have not been successful. I recall speaking to people associated with the chicken producers and extolling the virtues of eating the skin of the chicken. Their enthusiasm was somewhat muted which led me to think that they were co-opted by the conventional paradigm even though one would think that a large movement towards a LCHF approach would be beneficial to their industry.
I don’t know how many of my Canadian colleagues subscribe to LCHF. I do know that their interest is high when I speak at CME events. Unfortunately, I think that enthusiasm so far has translated into a handful of practitioners who are actually applying the diet. I can think of maybe four or five in British Columbia. There would be maybe a couple dozen in the country as a whole. I am working to change that, however!
“Dr Andreas Eenfeldt has chimed in, as well …”
I can believe Dr. Eenfledt’s claim that they may not be eating sugar/HFCS, etc.
I’m not so sure about the “brown rice” thing, since I think they started polishing their rice quite a while back. I’m also sceptical about their high level of physical activity.
When we get to his three more factors, the wheels seem to be coming off. With “poverty” we’re back to “calories”. Really? Stefansson writes of women in the Arctic sitting around indoors in winter — because it was too cold to go out — eating plenty and doing little but not getting fat.
“Food reward” is really just so unconvincing. Enough said. I’m not sure on “genetics” either — this seems to mean that they look thin, but this really just means that they’re under-muscled. But he said earlier in the article that they were active and not riding around in cars! And then there are those North American aboriginal peoples who were described as muscular “giants” by early explorers and who could hunt bison on foot; if they walked across the frozen Bering Strait, they’re as Asian genetically as people in Japan. Maybe the difference is NOT “genetic” but that they got the right food to eat.
In fine, I see his comment about sugar (over-processed food in general?) but I’m sceptical about the rest.
Here’s one more (possibly false) trail. What about disrupted gut flora — caused, for example, by antibiotics, over-chorination of tap-water, and perhaps over-cleanlness in general? Is this playing into obesity as well?
Dr Jay’s Reply:
I agree that it is problematic to make simplistic assumptions. I think the biggest mistake is to view past practices through the lens of current dogma. This leads to bizarre conclusion like the idea that the Inuit ate a high protein diet rather than a high fat diet (this has actually been proposed by a contemporary nutritional researcher).
The role of gut flora is an intriguing issue. I am aware of research where the fecal contents of the guts of Zucker rats, which are genetically predisposed to be obese, are injected into the guts of normal rats. The normal rats then become obese. This raises interesting questions about the etiology of weight gain, obviously. It certainly deflects us away from the supra-tentorial hypotheses, like food reward. I don’t know the answer but it does raise intriguing questions.
Skinny people are almost always “stimulant addicts” and to a high degree. — So are fat people, but they consume different ratios of fat, protein and carbohydrates. — High on the carbohydrates, for the skinny.
High on the fat and carbohydrates, for the fat people.
Re: fat ratios. It was heartening this morning to open up my daily posting from Dr. Mercola.com. The headline story recommended that over 50% of daily calories should come from saturated fat. Bravo, Mr. Mercola. Also, I just finished reading “Catching Fire” by R. Wrangham which was cited in the bibliography of “The Vegetarian Myth” by Lierre Keith. I hope that most of MBFD bloggers have read Veg. Myth. and I recommend browsing its bibliography because it provides lots of good reading paths and web links to explore.
Dr Jay’s Reply:
I’ll have to get around to reading the “Vegetarian Myth” at some point. Maybe the next time I find myself on a beach.