For those of you who aren't familiar with him, Dr. John McDougall is a doctor and diet/health advocate who recommends a very low fat, high starch, whole food vegan diet to control weight and avoid chronic disease. He's been at it for a long time, and he's a major figure in the "plant-based diet" community (i.e., a diet including little or no animal foods).
Dr. McDougall invited me to participate in his 3-day Advanced Study Weekend retreat in Santa Rosa, CA. My job was to give my talk on insulin and obesity, and participate in a panel discussion/debate with Dr. McDougall in which we sorted through issues related to low-carb, Paleo, and the health implications of eating animal foods. I was glad to receive the invitation, because I don't see myself as a diet partisan, and I believe that my evidence-based information is applicable to a variety of diet styles. I saw the Weekend as an opportunity to extend my thoughts to a new community, challenge myself, and maybe even learn a thing or two. It was particularly interesting to compare and contrast the Advanced Study Weekend with the Ancestral Health Symposium, which is more Paleo- and low-carb-friendly.
The attendees were a lot older than AHS attendees. I estimate that most of them were in their 60s, although there were some young people in attendance.
I don't place too much emphasis on peoples' personal appearance at conferences like this. You don't know what a person's background, genetics, or personal struggles may be, you don't know how closely they adhere to the program, and you don't know to what degree a group of people might be self-selected for particular traits*. But I will note that Dr. McDougall, his family, and many of the other starch-based/plant-based diet advocates tended to be extremely lean with low fat and muscle mass. They also tended to have a healthy and energetic appearance and demeanor. As I would expect, decades of exceptionally high starch intake hasn't made them obese or obviously ill.
Dr. McDougall and his family were extremely gracious, despite the fact that we clearly disagree on certain matters, and I was expected to air my disagreements to the crowd (to be clear, there are also many points of agreement). Actually-- that was part of the point-- to bring in people with alternative, evidence-based viewpoints. I didn't know Dr. McDougall before last weekend, so I didn't know to what extent he really wanted to give my views a fair shake, but in retrospect he was sincere.
I wasn't sure what to expect from the audience, since I was (among other things) defending the position that eating meat is natural for humans and can be part of a healthy diet. There were a few furrowed brows here and there as I spoke, but overall people were gracious, welcoming, and seemed genuinely receptive to my views. The beliefs I encountered from attendees ranged from evidence-based to the types of scaremongering you might find on an Internet diet forum. For example, some of them seemed to be convinced that meat is full of parasites, and if we eat it (even cooked), we'll acquire those parasites.
I spent the better part of three days eating a diet prepared according to Dr. McDougall's specifications. I was looking forward to the opportunity to try a new diet style. Meals contained zero added fat, zero animal food, and focused on starchy whole grains, beans, and root vegetables with some colorful vegetables as well. Potatoes are a central part of his diet and they appeared at every meal. No alcohol was served, and the only caffeine was tea.
The food was low in calorie density and bland, although not unpleasant. It's definitely a reduced-reward diet. I had no problem eating it for three days. I ate to fullness, but I'm sure I ate fewer calories than usual and lost a bit of weight. I felt good and had no trouble with hunger or fatigue; in fact, my appetite seemed to be suppressed somewhat. I experienced some mild digestive distress, perhaps from the large quantity of beans and onions in the food. My sinuses also became a bit stuffed, which is unusual. I'm not sure if that was related to the food, but it did clear up as soon as I returned home and began eating my usual diet.
The panel discussion/debate was between Dr. McDougall and I, and was moderated by John Mackey, co-CEO of Whole Foods. The goal was to discuss/debate low-carb, Paleo, vegan, and other aspects of diet, and explore the reasons for the popularity of low-carb and Paleo. We kicked it off by playing a news report on the recent low-carb vs. low-fat study, and the National Geographic video of an anthropologist claiming that the "real" hunter-gather diet is low in meat and high in starch (to see why other anthropologists tend to disagree with her, follow these links: 1, 2).
Dr. McDougall is baffled by the popularity of low-carb and Paleo. To me, the popularity of low-carb boils down to two factors: 1) It's an exciting, contrary viewpoint. People love to hear that the government and the ivory-tower eggheads were wrong. The print media is struggling mightily right now to keep eyeballs on the page, and they seem to be shifting to increasingly sensationalist tactics to survive. 2) It can be effective. Many people are losing weight and apparently improving their health using low-carbohydrate diets, and some of these people were failed by low-fat diets. It wouldn't be so popular if it didn't have some level of effectiveness.
I explained the rationale for the Paleo diet, as well as the rationale for an agriculturalist/horticulturalist-type ancestral diet centered around starchy foods with a modest amount of meat, eggs, and/or dairy. I wanted to present an ancestral option that bears some resemblance to what the audience is already eating. I didn't have time to deploy the full ancestral argument, but I think I had enough time to make a compelling case for it. I think the audience became more receptive when I explained that I wasn't advocating for a high-meat or low-carb dietary style as the optimal diet for humans. Overall my contribution seemed well received.
I also made the point that seemingly diametrically opposed diet philosophies, such as low-fat, low-carb, Paleo, and vegan, can all cause weight loss and apparent cardiometabolic improvements. What they have in common is that they all restrict something, they all eliminate most common junk foods, and they all make us think hard about what's going into our mouths. In general, the more restrictive the diet, the more weight loss it causes, and typically the greater the metabolic improvement.
We went on to discuss my full-fat dairy paper, vegan diets for children, the genetic and digestive basis for dietary adaptation, and a few other topics.
John Mackey was a great moderator-- fair and tough. Mackey is modest and unassuming but also sharp. I'm sorry I had to miss his talk on Sunday, because I wanted to connect with my friends who had driven from San Francisco to hear my talk. I entered the room just in time to witness people jumping to their feet in applause. I look forward to watching the talk when it's posted online.
I gave an expanded version of my 2013 AHS talk "Insulin and Obesity: Reconciling Conflicting Evidence". I argued that the evidence supports the hypothesis that obesity increases circulating insulin, but is difficult to reconcile with the hypothesis that increased insulin leads to obesity. Furthermore, the latter hypothesis, at least its most popular incarnation, is based on a superficial understanding of insulin biology.
The talk was well received, although it may have been a little bit too technical for a portion of the audience. It's not hard to convince people that insulin doesn't cause obesity when they've been eating extremely high-starch diets for years and, if anything, have lost fat.
I was honored that my friends Drs. Lynda Frassetto and Ashley Mason (UCSF) drove up to hear me speak at 8:00 am on a Sunday morning.
Dr. McDougall presented first on Friday. It was a good opportunity for me to learn about his views. Essentially, he believes that humans are designed to eat a vegan, low-fat, starchy, whole food diet, although he acknowledges that humans have hardly ever been vegan historically. Animal foods and added fats cause "food poisoning", and "the fat you eat is the fat you wear". He believes that a low-fat/high-starch diet offers a metabolic advantage, in other words that you can eat more calories on this type of diet without gaining fat. It's interesting to note the parallels between the low-fat and low-carb communities in this respect. He thinks physical activity and other aspects of lifestyle are much less important than diet. He recommends B12 supplementation, although somewhat reluctantly.
He and I may not agree on everything, but I do believe-- and the research backs this up-- that this type of diet can cause weight loss and improvements in cardiovascular and metabolic health. They make the point, which is fair, that the typical low-fat diet that gets whupped by low-carb diets in controlled trials is a wimpy version of what they recommend. Dr. Barnard's studies show that a very low-fat vegan diet causes more weight loss and metabolic improvement than a typical low-fat diet, and in fact the results he achieves look very similar to what is reported in low-carb diet studies.
It may sound counterintuitive, but there's even credible research suggesting that low-fat high-complex-starch diets can help type 2 diabetics achieve better glucose control and reduce insulin needs. It's really interesting for me to encounter almost identical anecdotes from the low-carbohydrate crowd and the low-fat vegan crowd: I lost 100 pounds, got off my diabetes medications, my blood lipids are much better now, etc. I'm quite convinced that many people do well on the McDougall diet, and more remarkably, that a significant number of people can stick with it and even seem to enjoy it.
On Saturday, I attended a talk by Dr. Neal Barnard. Dr. Barnard is the president of the Physicians Committee for Responsible Medicine, which would be more aptly named the Physicians Committee for Plant-Based Diet Advocacy. His activities are a mix of laudable scientific and public health achievements, and overzealous diet advocacy. Some of his scientific claims were a bit facile, for example, that lipid stores in muscle cells cause insulin resistance, and that this is a direct result of eating dietary fat**.
Stanford Research Dr. Christopher Gardner gave an enjoyable, meandering talk that touched on his diet trials, as well as his forays into exploring what motivates people to make positive changes in their diets. Apparently, most people aren't particularly motivated by health. They're more motivated by immediate, positive gains like feeling better.
The Absurd Talk Award goes to Gary Null, who I had never heard of but apparently has a large following. Null started off by bragging that he's the #1 quack on the website QuackWatch, which he interprets as evidence that the mainstream medical and scientific community is conspiring against him. He went on to 'educate' us about how vaccines cause autism, and how he had developed cures for cancer, AIDS, and other diseases.
Null also claimed, hilariously, that his research had revealed that beans are actually a complete source of protein, and that he had submitted his findings to 400 scientific journals and none of them had so much as responded. Ummm... I could send three pages of completely illegible jibberish to almost any journal in the world, and if I submitted it properly, I'd receive a response. The response would be "no", of course, because my submission would be scientifically worthless. Furthermore, are there even 400 scientific journals in the world that are interested in the amino acid composition of beans? I doubt it, but maybe I'm just part of the conspiracy... In any case, I have a newfound respect for QuackWatch.
On Sunday, I saw Dr. Dean Ornish speak. Dr. Ornish gets some flack from the low-carb/Paleo community, but I actually appreciated his talk. He believes that a comprehensive diet and lifestyle program, including a low-fat/low-animal food diet, is the best way to improve health. I have no doubt that his program is effective, but that's not what I appreciated the most about his talk. I appreciate his ongoing efforts to evaluate diet and lifestyle modification using the tools of modern science. I also appreciate his thoughtful perspective on how to get people to comply with a healthy diet and lifestyle sustainably and compassionately.
I'm glad I attended, and I think it was useful for all involved.
If someone put a gun to my head and forced me to choose between the McDougall diet and the Atkins diet for the rest of my life, I'd probably choose the McDougall diet. Most of the people I met seem to be aging gracefully on the McDougall diet, and I still feel there are questions to be answered about the long-term health impacts of Atkins-type diets. I still have major reservations about a 100 percent vegan diet, however, particularly for children.
Fortunately, no one is putting a gun to my head, so I'll stick with my starch-based diet that includes lots of nuts and a moderate amount of olive oil, butter, meat, seafood, eggs, and whole dairy.
* It was disappointing to hear multiple speakers pick on the appearance of Dr. Robert Atkins, the fact that he died earlier than them, and the circumstances of his death. From what I understand, there's a lot of uncertainty surrounding his health at the time of his death, but it was repeatedly implied that his diet caused him to have cardiovascular disease and contributed to his death (which was actually due to head trauma).
** Athletes have elevated muscle fat (intramyocellular lipid, IML) stores, yet also have exceptionally insulin-sensitive muscles. In that case, increased muscle fat seems to be a positive adaptation to high energy demands on muscle tissue. Obese people also have elevated IML stores, but in that case it's associated with insulin resistance. So do the elevated IML stores themselves cause insulin resistance? Probably not. In the case of obesity, they're probably at least in part a marker of excess energy availability to muscle tissue. When a cell is exposed to more lipid than it can burn, it accumulates IML but also lipid metabolites such as diacylglycerols, Acyl-CoAs, and ceramides, and these metabolites shut down insulin signaling as if the cell is saying "Stop sending in more energy! I already have too much!" How does this happen? It's probably mostly a result of the failure of enlarged, insulin-resistant adipose tissue to adequately trap fatty acids, causing excessive fatty acid exposure of lean tissues. When insulin sensitivity is measured by gold-standard methods, dietary fat doesn't seem to have much impact on insulin sensitivity until you get to the extremes.