Wednesday, October 1, 2014

Metabolic Effects of a Traditional Asian High-carbohydrate Diet

A recent study supports the notion that an 'ancestral diet' focused around high-starch agricultural foods can cultivate leanness and metabolic health.

John McDougall gave Christopher Gardner a hard time at the McDougall Advanced Study Weekend.  Dr. Gardner conducts high-profile randomized controlled trials (RCTs) at Stanford to compare the effectiveness of a variety of diets for weight loss, cardiovascular and metabolic health.  The "A to Z Study", in which Atkins, Zone, Ornish, and LEARN diets were pitted against one another for one year, is one of his best-known trials (1).

Dr. McDougall asked a simple question: why haven't these trials evaluated the diet that has sustained the large majority of the world's population for the last several thousand years?  This is an agriculturalist or horticulturalist diet based around starchy foods such as grains, tubers, legumes, and plantains, and containing little fat or animal foods.  Researchers have studied a number of cultures eating this way, and have usually found them to be lean, with good cardiovascular and metabolic health.  Why not devote resources to studying this time-tested ancestral diet?  I think it's a fair question.

The reason seems to boil down to practicality: it's hard to get people to eat that way for a long period of time.  It's not easy to get people to adhere to a relatively bland 'third world diet', and the NIH isn't overly excited about studying a diet style that can't reasonably be applied to the general population of an affluent nation.

The Study

Still, we get scientific hints every now and then that this style of eating, if executed intelligently, is part of the spectrum of ancestral diets that can support good health in most people.  Such a study was recently published in PLoS One, which is an open-access journal so you can all have a look if you want (2).

William C. Hsu and colleagues randomly assigned 28 Asian-Americans and 22 Caucasian-Americans, all of which were deemed at risk of developing type 2 diabetes, to two groups:
  1. 16 weeks of a "typical Western diet" (TWD), presumably representative of the current US diet.  The methods provide very little information about what the TWD actually was, besides providing 50% of calories from carbohydrate, 16% from protein, 34% from fat, and 6 g of fiber per 1,000 kcal of food.
  2. 8 weeks of a TWD followed by 8 weeks of a "traditional Asian diet" (TAD).  The methods provide very little information about what the TAD actually was, besides providing 70% of calories from carbohydrate, 15% from protein, 15% from fat, and 15 g of fiber per 1,000 kcal of food.
Basically, it was a high-carb, low-fat, high-fiber diet vs. a more typical affluent diet.  The participants were fed enough of each diet to maintain body weight, based on estimated calorie requirements, and energy intake was deliberately adjusted to avoid weight loss.  The researchers provided all food by delivery during the 16-week study, but since participants weren't housed at the research facility, there's no way to be certain of exactly how well they complied.  However, compliance tends to be good when researchers provide all food like this (people like free food).

There were a number of dropouts in the first 8 weeks of the study, leaving 33 people in the intervention group and only 7 in the control group.  This unfortunate turn of events does weaken the study.

The Results

Despite the conscious attempt to prevent weight changes, participants gained weight and fat during the TWD phase and lost weight and fat during the TAD phase.

While eating the TAD, participants experienced a few metabolic changes that appear beneficial.  The amount of circulating insulin and glucose following a glucose challenge decreased, estimated insulin sensitivity increased, and LDL decreased (although so did HDL).  This is despite the fact that they used "intent-to-treat" analysis that lumps dropouts together with completers.

The participants of Asian descent reacted similarly to the diet as those of Caucasian descent.


This study had some weaknesses, due both to its unusual design and the unfortunate (and asymmetrical) number of dropouts.  However, it adds to the evidence that horticultural and agricultural diets centered around unrefined carbohydrate can benefit weight and health, relative to the typical affluent diet.

Some people have speculated that very low-fat, or very low-carbohydrate, diets may be able to cause weight loss independently of their calorie content.  This study could certainly add fuel to that fire.  However, due to the less-than-perfect control the researchers had over the subjects' diets, I'd be cautious about making that conclusion.  The best available evidence continues to suggest that the calorie value of food impacts body fatness, but macronutrient composition doesn't.  I believe we'll eventually learn that the story is a bit more complex than that, but the boring adage "a calorie is a calorie" is the interpretation the evidence currently supports.

Although obesity and cardiovascular/metabolic disease are rare in horticultural and agricultural societies, that doesn't mean these cultures are always healthy.  Some of them suffer from diet-related health conditions, often caused by nutrient deficiencies.  According to my understanding, these tend to result from one of three causes:
  • Low diet diversity.  Eating an excessively grain-heavy diet can lead to mineral and vitamin deficiency disorders, including mineral deficiency rickets, vitamin A deficiency, scurvy, anemia, and pellagra.  Eating starchy tubers to the exclusion of other foods can lead to protein and folate deficiency.  Solution: eat a diverse diet that includes animal foods, starchy tubers, vegetables, and nuts.  I speculate that vegetables and dairy are particularly valuable to agriculturalists because they complement the shortcomings of a grain-based diet.
  • Nutrient-poor soil.  Some soils are deficient in specific minerals, and this can translate to deficient food.  For example, iodine deficiency cretinism used to be common in the Alps due to iodine-poor soil, leading to endemic mental retardation.  Even though cretinism is rare in the Alps today, the term crétin des Alpes, or simply crétin, remains a common insult in France.  Parts of the Midwestern US also have iodine-poor soil, and iodine deficiency goiter was common there until the introduction of iodized salt.  Solution: eat diverse foods from a variety of places, which is the default today anyway.
  • Inappropriate food preparation.  Traditional preparation methods such as fermentation and nixtamalization are used throughout the world to increase the nutritional value of grains (3).  Cultures that don't apply these methods are more susceptible to deficiency diseases.  For example, in Iran, traditional agriculturalists who rely heavily on unfermented whole wheat develop mineral deficiency rickets and osteomalacia, despite spending much of the day in the sun; the same effect has also been noted in other populations  (4, 5).  The adoption of corn throughout the world (because of its incredible calorie productivity) was accompanied by a wave of pellagra, caused by niacin deficiency.  Native Americans who had been eating corn for thousands of years didn't suffer from pellagra because they pre-treated their corn with the mineral lime (calcium hydroxide) to unlock its niacin and make it a good source of calcium-- a process called nixtamalization-- but this knowledge didn't accompany the plant to other parts of the world.  Solution: use traditional grain preparation methods and/or eat a diet that doesn't rely too heavily on grains.
My opinion is that grains in general can be part of a diverse healthy diet, but very grain-heavy diets present nutritional challenges that must be managed.  I also believe that wheat is problematic for some people, for multiple reasons*, although many people probably tolerate it just fine.  There is no nutritional need for grains in the diet, including wheat, and their primary virtues are their low cost and good taste.

* 1) The gluten-provoked autoimmune disorder celiac disease affects nearly 1% of the US population, and some evidence suggests that the prevalence increases with age.  People with celiac disease have a higher mortality risk than the general population, and most cases remain undiagnosed.  That alone is a huge chronic disease burden attributable to a single food.  2) Although research is ongoing and the area remains controversial, some research suggests that certain people without celiac disease are nevertheless sensitive to gluten.  The true prevalence of non-celiac gluten sensitivity remains unknown.  3) Wheat is a major source of FODMAPs, a class of fermentable fibers that exacerbates the extremely common digestive condition irritable bowel syndrome (present in 10-20% of Americans).  Wheat is one of many dietary sources of FODMAPs, however it's one of the largest in US and European diets.  4) Wheat is usually consumed after having been ground into flour and baked, often in combination with fats, sugars, and other desirable ingredients.  This creates highly palatable, calorie-dense foods that lead to overconsumption.


Tucker Goodrich said...

"The methods provide very little information about what the TAD actually was..."

So how do we explain the fact that metabolic syndrome is skyrocketing in Asia, far worse than it is in the West?

Are they simply adopting harmful elements of the Western diet wholesale? (Wheat, sugar, and seed oils, that is...)

From Whole Health Source of a few years ago, that would be my interpretation. I'm interested to hear what you say today.

stephenhow said...

To be clear, Dr. McDougall doesn't claim any metabolic advantage to a low-fat, whole-foods, plant-based diet. Calories-in/Calories-out is always the rule, but it's highly unlikely that you'll overeat on a McDougall diet (no food reward).

But yes, Dr. McDougall does claim that a potato-exclusive diet will keep a person healthy. It does seem that potatoes are a source of complete protein:

So far, I haven't read or heard anything from Dr. McDougall that looks false or inaccurate. I tend to disagree with his vegan leanings, because I like to eat meat. He thinks meat is unnecessary in the human diet, which it probably is.

Sunny Sattva said...

Thank you for a very intelligent interpretation of that survey. I like the idea of the McDougall or starch centric 'agricultural peasant' diet or whatever we shall term it - to be included under the umbrella of Ancestral diets, which conveys a gravitas and respect. It would relieve pressure on the debate of paleo/WAP vs vegan. Not this or that; but this and that.
Interesting that the diet's effectiveness was shown amongst Caucasians and Asians.
This: 'a diet style that can't reasonably be applied to the general population of an affluent nation' is brilliant as it is true- requiring a shift in perception in terms of what we eat and why. Eating for pleasure, leisure convenience, the civilised palate is addicted to sensation, much as the civilised mind is addicted to thought. There are individuals in the US and elsewhere working this diet with success and aplomb; developing recipe repetoire etc. Its a skilful and creative way to approach food. I would love to see an interest in traditional starch based cuisines. As you say, balancing out nutritional deficiencies with judicious amounts of nuts, maybe even animal foods. Very very helpful, I look forward to the broadening out of this conversation, let's continue to keep an open mind and see what emerges!

t said...

" I speculate that vegetables and dairy are particularly valuable to agriculturalists because they complement the shortcomings of a grain-based diet."

This was George Cahill’s conclusion 90 years ago…

Stephan Guyenet said...

Hi Tucker,

Yes, I think that's basically it. Some would say their diet is "westernizing", but I think a more accurate way of putting it is that their diet and food environment are simply becoming more affluent. I don't think it's just white flour, seed oils and sugar though, it's broader dietary changes in addition. Also, their lifestyle is changing dramatically as well, becoming more sedentary. More air pollution. Everything that goes along with an affluent lifestyle.

Hi Stephen How,

I'm not very familiar with McDougall's writing, but at the Advanced Study Weekend he clearly stated that his diet is slimming even if you eat excess calories. He didn't use the phrase "metabolic advantage" but his statements were consistent with that phrase.

It is absolutely true that potatoes have almost everything you need to stay in good health for a long time. You'll eventually need some B12, vitamin A, and perhaps some essential fatty acids, but other than that potatoes have everything you need. Few other foods can make that claim.

Hi Sunny,

Thanks. I think most people would have a hard time eating the traditional agricultural diet of many parts of the world. Typically, it's a single plain starchy staple at every meal (e.g., corn pudding, cassava, or chappati), which comprises the majority of the meal, plus smaller amounts of other foods like beans, vegetables, and sometimes a bit of meat or dairy. As you said, we're accustomed to constant entertainment of the palate, and we're deeply attached to it. Changing lifelong food habits isn't easy.

Bård said...

You say that the study had some weaknesses, and I guess you're right. Every study has weaknesses. But the strenghths are obvious. This study is one of few that actually is relevant to informing people on a way to eat to increase metabolic health and lose weight. Also, as the authors report, compliance was generally good at 90% of calories and in spite of a few dropouts. Maybe they'll keep even closer tabs with the compliance issue in a larger and broader study, when that hopefully is done. The TAD was regarded as a bit more palatible than TWD according to the article. Therefore your reasoning that blandness is a limiting factor for this style of eating may not apply.

Bloggo said...

I've been eating a McDougall type diet to 90% compliance for nearly 4 years. I lost 25-30% of my body weight in the first year (50+ lbs) and have kept a BMI below 20 for the duration. It's easy to do, I'm always full and the food tastes great once food addictions (salt, simple sugars, oils and other fats) are eliminated. It's referred to as whole plant based, SOS-free diet in "the club." Many days, I'd rather eat salad and cold baked potatoes out of the fridge than any high-reward food offered to me. I'm sure this will work wonders for most anyone with human genetics but there is a learning curve and lots of pushback because it's so counter to current norms.

Most people overthink it. In a nutshell, the basic idea is calorie density. Simple. Eat mostly or exclusively foods in the calorie range of ~600-700 calories or BELOW. Eliminate any of the foods in that range you don't like, that don't agree with you, or if they trigger overeating (gluten for celiac, for example). There are so many foods to choose from that it's not a hardship and there's no danger of not getting your nutrients elsewhere. Feel full, healthy, and be trim. 100% compliance is recommended. Reason being, the slippery slope of addiction. Most people don't do moderation well. If you're one of those can do moderation, figure what and how much but you'll never get McDougall to say moderation is ok because I'm sure he's seen it backfire on many patients.

If you are not familiar with the work of Alan Goldhamer and Doug Lisle at True North, look into it. Also, I suggest as much McDougall as you can read and listen to. Lastly, the work of Jeff Novick. Waiting for studies on this? The mainstream will never catch up to this or allow it to take hold. It would mean a drastic change in our food production and economy. Vested interests and all that. So confusion reigns where practical simplicity ought to be the order of the day.

brec said...

Stephan, in a comment here you said, "I'm not very familiar with McDougall's writing, but at the Advanced Study Weekend he clearly stated that his diet is slimming even if you eat excess calories."

I'd like to verify that he said that. Do you recall any context that might help me locate the statement via video? Was it in response to your talk? During the Q&A with John Mackey? Thanks...

brec said...

Bloggo said, "Eat mostly or exclusively foods in the calorie range of ~600-700 calories or BELOW."

To clarify: that's calories per pound.

Tim said...

Lest not forget that a traditional Mediterranean dietary pattern provides metabolic benefits similar to a traditional Asian diet, while allowing for a more diverse macronutrient intake range and choice of food.

I don't see why I should bereave myself of so many pleasures of healthy eating and cut mself off of centuries of ancestral culinary tradition by turning to a "SOS-free" McDougall type diet. Sprinkling extra virgin olive oil and some sea salt on my salad doesn't make me more susceptible to become addicted to processed junk food - quite the opposite!

For people, however, who have a strong ascetic leaning, such a diet may be the way to go. The traditional Asian diet is more about abstinence, whereas the Mediterranean diet is more about moderation. I always prefer the latter, when possible.

How does it come that the traditional Mediterranean diet included large amounts of fat (up to 40%) and yet yield a metabolically healthy lean phenotype (as recently confirmed by the PREDIMED trial)? It is not only the fact that most of the fat is monounsaturated and that the polyunsaturated facts (n-6/n-3) are evolutionary balanced, but also that they are accompanied by large amounts of polyphenols, not only from the olive oil itself but also from fruits, vegetables and red wine.

Food always represents a complex package being part of a larger environmental context. There is, for example, a world of a difference between virgin olive oil and artisanal cheese in context of a traditinal diet and refined seed oil and industrial cheese within a fast food context - even if they are similar by their macronutrient content. It is not due to the minor compounds (such as polyphenols, rare fatty acids and fermenation products) missing from the latter but also the complex interactions between different elements of the dietary pattern (e.g. a fat-rich meal causes postprandial oxidative stress and endothelial impairment but not if accompanied by a rich source of polyphenols, such as a glas of red wine).

Ironically, these arguments resemble T. Colin Campbell's recent criticism of the rampant reductionism in nutritional science. Yet there is clearly no one more obsessed with abstract macronutrient ratios than the vegan (and low-carb) crowd.

Stephan Guyenet said...

Hi Brec,

I recall him making comments to that effect during our discussion/debate Saturday evening. He implicated dietary fat in obesity in a manner that suggested that he doesn't think it's oxidized effectively (where does it go? out your ears?).

I don't remember exactly what else he said, but he made another comment during that debate that suggested he believes that fat is more fattening than the calories it provides. I disagreed with him on that, pointing out that the best controlled RCTs have shown that macros are irrelevant when kcals are controlled.

I don't remember all the details, but I was left with the distinct impression that he doesn't believe kcals are that important for adiposity.

Bloggo said...

Bloggo said, "Eat mostly or exclusively foods in the calorie range of ~600-700 calories or BELOW."

Brec wrote: "To clarify: that's calories per pound."

Yes, thanks for the correction.

Bloggo said...

Tim, oil and the Mediteranian diet.

Aaron said...

Stephan, besides your response to Tucker earlier on why metabolic syndrome is skyrocketing in Asia. Isn't it probably just the fact that they have a high pool of potentially insulin resistant people vs that of Europe (in general). I think many studies have show that. So, if they add sugar, wheat,seed oils etc, they are REALLY at risk.

Stephan Guyenet said...

Hi Aaron,

They are thought to be more genetically susceptible to MetSyn, such that it takes less of a diet/lifestyle insult, and less excess fat mass, to result in MetSyn. But I think the diet/lifestyle factors that drive the process are probably similar.

Stephan Guyenet said...

Hi Bloggo,

Regarding the oil thing, I do think it's interesting to note that the Cretans had the lowest heart attack risk of anyone Ancel Keys studied in the 7 Countries Study, and their diet was high in olive oil. They got a similar percentage of calories from fat as we do in the modern US, although it was mostly monounsaturated. Their heart attack risk was slightly lower than the next-lowest culture, which was a Japanese region with high starch intake and very, very low fat intake.

Seems to me that olive oil can be compatible with very low heart attack risk, at least in the context of a traditionally-living society. Much other evidence supports the beneficial properties of extra-virgin olive oil.

Aaron said...

Stephan, the Cretans probably ate a somewhat caloric restricted diet with less protein than a lot of cultures. Also, in the new tests on EVOO, it has been shown to have very little to no AGEs which is probably what it is such a great fat to consume. (Also that it is low in polys)

Bloggo said...

Stephan, I'll go so far as to say that the olive oil had little or no NEGATIVE effect. Given all other aspects of the Cretan diet and lifestyle, I don't see why anyone would focus on olive oil as the "health food" that made the difference. Indeed, in today's developed and developing countries where obesity is reaching epidemic levels (including Crete), it's quite an odd idea to seek a low nutrient, processed food calorie bomb to force feed ourselves.

The point here is that olive oil is not the magic bullet that made populations along the Mediterranean in the 1950s so healthy. “Olive oil was simply a bellweather, or marker, for other features of the Mediterranean diet, like plenty of fruits, vegetables, whole grains, and exercise, that were in fact healthful,” argues Jeff Novick.

That’s what new research is finding. In a recent study in the New England Journal of Medicine, scientists followed for years the diets and health of 22,043 adults in Greece.(7) Adherence to the traditional Mediterranean diet was assessed by a 10-point scale that incorporated the key facets of the diet, including an abundance of plant food (fruits, vegetables, whole-grain cereals, nuts, and legumes), olive oil as the main source of fat, and low-to-moderate amounts of fish and poultry.

Though higher adherence to a Mediterranean diet was associated with significantly lower death rates, olive oil itself was “associated with only a small and nonsignificant reduction in mortality,” wrote Dr. Frank B. Hu of Harvard Medical School in an editorial accompanying the study.(8)

janu said...

I'm from southern part of India and have a fair idea of what our ancestors have been traditionally eating. Mostly people have adhered to the traditional way of making food until recently. In recent times food preparation methods have considerably changed due to convenience and the need to adapt to the fast paced life. Our traditional staple had always been parboiled rice (which has most of the nutrients from the bran absorbed into it) as opposed to the currently adopted refined white raw rice. The rice was always accompanied with legumes and vegetables. And for breakfast/dinner we had the idlis and dosas and legume crepes (fermented foods). We had good amount of dairy mostly cultured (yogurt). For fats we used mechanically expelled peanut oil, sesame oil and coconut oil and ghee (made from yogurt traditionally). We used good amount of jaggery (unrefined sugar) and coconut. It was mostly wheat free diet. It’s really sad that people always think about chapathi/roti when it comes to Indian food. There is whole different world out there when you travel down south of India.

I’m sure our ancestors were way more healthy, had great energy levels and did lot more physical work than us. I’m sure obesity would have hardly been among them. Eating meat even among non-vegetarians was never a daily affair mostly attributed to religious beliefs.

I must say our traditional food is highly palatable and you would be blown away by the variety if you are exposed to our traditional recipe books. Agreed, that it might not be palatable to a tongue that has not acquired the taste. But whoever has acquired it’s taste don’t turn back.

tomR said...

About processing - some recipes call for both soaking and fermenting, eg. some versions of handvo recipes

The other difference between Western and Asian cuisines, which puts McDougall one in the western camp, is the high use of spices, aromatic foods in Asia. Ginger, turmeric, cumin, herbs etc. Asian food is not bland. It's also important how high variety of items they can they put into it - sometimes I counted like >20 ingredients in Asian dish. Preparation based on mixing things helps there.

tomR said...

When using the term ancestral it's important to note that who our ancestors were. It's pretty clear now, that we are disproportionately descendant from the rich people. For example Gregory Clark's work Farewell to Alms says, that 90% of English at the dawn of the Industrial Revolution come from top 10% of the richest of the Medieval Period.
Thus the ancestral diet - for the name to be correct - has to be the diet of the richer strata of the past. Not a poor peasant diet.
McDougall doesn't get it. In his book The Starch Solution, the chapter about the ancestral diets is a comparison between the diet of the rich, that contained a lot of meat and according to him led to denegerative dieseases, with the starch-based diets of the poorer, which according to him gave the eaters good physical conditions - and he calls these starch diets of the poor the real ancestral diets. Going into the opposite direction of what he should... in a chapter that was supposed to uncover what the real ancestral diet was!

J Bean said...

Olive oil wasn't simply a source of fat in the traditional Greek or Cretan diet. It was also a major source of calories. Rather than storing food for the winter in the form of grains or tubers, the calories needed to ensure winter survival were mostly stored as olive oil. It's a unique diet, low in both protein and carbs.

t said...

"I speculate that vegetables and dairy are particularly valuable to agriculturalists because they complement the shortcomings of a grain-based diet."
This was George Cahill’s conclusion 90 years ago…"

When I posted this earlier.. I meant McCollum, not Cahill..!
MacCollum's "Newer Knowledge of Nutrition" is pretty interesting

Honey Razwell said...

Hi Stephan, :)

Great points in your other article about vegans and vegetarians and how you respect the sacrifices they make. They likely are making the world better for us all. Dr. Filippenko once commented that we all collectively might have to CONSIDER being vegetarians to help the planet. Not for health reasons - but to sacrifice for the Earth.Even if it means eating less than optimal for ourselves, it could help our precious planet.

However, what bugs me is that researchers such as T. Colin Campbell and the various promoters of the lifestyle with agendas - misrepresent diets in China, Japan, Taiwan etc. The perfect land where nobody farts and everybody eats nothing but greens. LOL !!!!

These people eat plenty of quality animal foods- seafood etc. snakes and insects of ALL kinds. Rice is complimentary and often times noodles is the pick of the day. My sister-in-law is Chinese and my brother spent 4 years in Japan in the Navy.

Anybody who has ever seen Anthony Bourdain or Andrew Zimmern's TV shows knows that they eat a well balanced diet. Very well balanced I might add :) Ideal really.

It's not a "huge rice fest with a gigantic sized big bowl of just rice." Often it is noodles instead.And these items are only featured in the dish with an overall balance of animal foods and vegetables.

There is a strong low -carb backlash in the Blogpshere from the early 2004- 2007 Paleo days etc.These people go too far where they instead now recommend gorging on lots of carbs and huge rice bowls. The traditional diets of Thailand, China, Japan, Philippines etc. are just like any other culture- salt, sugar , fat and generally very well balanced. They are not carb-phobic, but they are not going nuts with them either. There soups often have beef and noodles etc. Ocotopus is common.

The United States' citizens often have this wrong idea of what they actually eat. Balance is the best representation.

I would not want to raise my risk for pancreatic cancer by ingesting lots of sugar everyday.A balanced diet tames this with the fat and protein.

You probably know this already though. :)

Take care, Stephan.


Meaderiote said...

I am not an expert at all but I do want to just say that Asians have adopted a lot of Western diet into their way of life and has caused obesity to rise. I was lean and a size 4 at 5' 7" after 4 kids until I migrated to America. I am now a size 10 and overweight. I am returning to my old style of eating that is eating fresh, and as much as possible avoid preserved foods. Its in everything here and scares me. Although I am still a healthy woman but all the salads and low fat low salt low carbs have only made me fatter. I ate a lot 5 meals a day back in Malaysia but small healthy fresh homemade meals. And the abundance of a variety of international foods as well have caused our digestive systems to go haywire. My 2 cents worth.

Yilin Li said...

Well, as Asian, I must say they need to clarify which part of Asia the study are trying to follow. For China, Japan and Korea, the common sense are: rice, vegetables and some meat consist of our daily diet. We don't like sugar or protein that much as Western diet, I would say the most important thing is that Asians Don't have the tradition to eat Desert after meal.

LivewellProsper said...

Another traditional adaptation for preparing grains is sourdough fermentation. Finnish people have higher rates of celiac but their traditional diet includes a lot of sourdough rye bread. Does the fermentation of sourdough neutralize the effects of gluten in rye sufficientky? Does sourdough have a benefit even if not neutralizing gluten?

thorn324 said...

Hello, t,

The book you referred to (_Newer Knowledge of Nutrition_) is by Elmer Verner McCollum. I post this in case others were, like I was, unsure of the spelling of the author's last name you provided and had difficulty finding the book.

Hello, Tim,

Dr. McDougall's recommended diet could not be described as an "SOS-free" way of eating: it does eschew all added oils/fats (as well any that are part of animal products & processed foods), but it includes some salt and sugars—albeit in moderation.

Hello, tomR,

When I read Dr. McDougall's reference to the "ancestral diet," I took it to refer to ancestors in a broader sense than (it seems) you did. Not every one is descended from the upper crust (even in the wider sense you give it) of England during the Industrial Revolution. My own ancestors made their way to the United States in the early part of the 20th Century, having left behind not the industrial sweatshops of an English-speaking country but rather the rural peasant lives of Eastern Europe. As it turns out, then, my ancestral diet (used it the sense you attached to that phrase) was as McDougall prescribes: starch-based (primarily potatoes) with the addition of vegetables (primarily onions, beets, & cabbage). Choosing from a variety of starches, vegetables, and fruits, I link to my human ancestors who came from Poland (certainly) but also from Japan & Africa & Central America.