TPNS 25: Interlude: Arthur De Vany
Saturday, March 24, 2012 at 11:43AM
Plant Positive

Primitive Nutrition 25:
Interlude: Arthur De Vany


In my first video you saw a picture of Arthur De Vany pulling his luxury SUV down his driveway.  Someone who would do something so unusual is surely worth a closer look.

De Vany looks good for his age so he is a big deal in the Paleo world.

I heard him on a podcast and thought he seemed pretty interesting so I bought his book.  I intended to spend more time on it but a short sampling had me pining for better things to read.

The cover illustration is promising.  It suggests De Vany understands the ancient baggage we carry in our body plans and organ functions going back all the way to our fish days.  Unfortunately, the content of the book doesn't live up to the cover.

It isn't important to me how someone uses evolution to rationalize  his or her diet as long as that diet is reasonably in line with the best modern science on nutrition.  Unfortunately, like Loren Cordain, De Vany has an unreasonable fixation on protein that he justifies through its ability to limit your appetite.  Once again, I doubt proto-humans struggling hand to mouth for survival would have found much advantage in appetite control strategies, and I find it hard to believe they would have cared about keeping off the extra inches around their waists.

De Vany says at the bottom of this slide that a diet lacking in protein will lead to obesity, and he provides a reference to support that view.  To the reference we go...

The reference is, amazingly, a study of protein consumption in grizzly bears.  I'm not kidding.  This is why I use pictures in these videos, folks.    Sometimes while researching Paleo I didn't know whether to laugh or cry, but laughter definitely feels right on this occasion!  Bears fed a low protein diet will keep eating until they get all the protein they need.  Now why might this be?  Would a bear commonly eat a low-protein diet?

Maybe someone out there would be kind enough to tell the esteemed economist that these godless killing machines

are classified as carnivores, unlike us, although they are functional omnivores.  High protein diets are the norm for them.

Grizzlies are actually a great example of the compromises that evolution produces in organisms.  They eat plants even though they aren't especially well adapted for that.

For modern bears, the most important protein sources are from plants.

This author went so far as to say they are often almost vegetarian.

Grizzlies do prefer animal meat and fat, but they can't always find it.  As a result, even grizzlies in the Arctic depend mostly on plants.  They are a more stable food source, which should give us a clue about what the stable food sources might have been for Paleolithic humans during the Last Glacial Maximum.

De Vany might want to check out this middle school level biology textbook to discover  that grizzly bears are not known for staying especially lean.  If you want to convince your readers that high-protein diets keep you lean, maybe bears aren't the best example for you to use.

Let's see what else he has for us in this reference.  He says the same preference for protein is found in humans.  It seems he has a study to back that up.  Turning the page...

There you see the title at the very top. Let's look at that one.

Here's the abstract.  Either Dr De Vany doesn’t understand this or I don‘t. Here's my take.  First, it's a study of mice, not humans.  Not that I'm complaining but he just said humans show this preference for protein and sent us to this study to support that.

So what does it say?  The study is in two parts.  Experiment 2 was about an amino acid supplement so I don't think that's what interests him.  Experiment 1 is the one we should think about.  The short version of my take on this is that it basically shows that rats don’t prefer either very high protein or very low protein diets.  The rats were only offered 5% or 35% protein diets. They weren’t offered anything in between. One is too high, the other is too low. It seems DeVany only got half the message here.  And I don’t know what this study has to do with feeling full.

I don't think this supports his argument very well.  Now I'm not disputing the fact that people have protein needs that must be met, no matter what their diet is.  I think De Vany is trying to tell us about the protein-leverage hypothesis, but he has just not chosen good studies to make his point.

The protein-leverage hypothesis states that humans, like other animals, have a requirement for protein intake that must be met.  If the foods in our diets are very low in protein, we'll end up eating more calories than we would otherwise in an effort to hit that protein requirement.  A better study in animals that De Vany could have used might have been this one, in which the food intake of spider monkeys seemed to be determined mostly by their protein needs.  However, they really didn't eat that much protein.   These monkeys were not Paleo.

That's the problem with this argument.  Studies of the protein-leverage hypothesis in healthy humans do not indicate that we need very high amounts of protein.

Instead, they point to rather moderate protein requirements, even when the diets studied included refined grains, sugars, and unhealthy fats. This study did not make much of an attempt at high nutrient-density, yet it still only indicated protein needs in the 15% range.  As any nutritionally aware vegan will tell you, a balanced whole food, plant based diet more or less automatically give you enough protein if you eat sufficient calories.

In the last portion of this end note he references a long technical paper by two low carb promoters saying there is a metabolic advantage to eating protein in terms of weight loss.   I'll look at the concept of metabolic advantage in the Better Than Low Carb videos.

This section was naturally of interest to me.  From the title you can tell right away that this economist is fully invested in the appeal to nature fallacy.

Getting into specifics, his thoughts on vegetarianism seem to be rather unsophisticated.  He says a vegetarian diet forces reliance on high-glycemic foods.  "There is no other way to obtain adequate calories," he says.

I don't understand why he would say something so easily refuted.  Just look at a glycemic index table.  I think I chose some pretty straightforward items to list, and you can tell they are all low to mid GI.

As for eating frequency, you can eat bigger meals, or simply be ok with snacking if that's a problem.  He says you can't be very active as a vegetarian unless you eat high-GI foods because you have to eat so often.  I think he doesn’t know the difference between glycemic index and calories.  Otherwise, this sentence makes no sense.

De Vany doesn't even try to present himself as a critical thinker here.  He complains about the few vegetarian students he knows who think a potato chip is a vegetable.  Kids these days, right, Art!  Tell me about it!  The old man has a point.

There is no question college students are often poor examples of proper nutriton, much less responsible alcohol intake or healthy sleeping patterns.  If you were considering a diet based on stressed and out of control kids away from home for the first time, Art has made a convincing case just for you.

He goes on.  Children who don't eat animal protein will have underdeveloped nervous systems and brains?  He then just goes on to say many, I guess not all, vegetarians he knows have terrible body composition?  They're "skinny-fat"?  Wait, what about the children not developing their brains?  Isn't he sort of burying the lede here?   Why skip that to make a catty remark about vegetarians being skinny-fat when you have that bombshell? Would someone please give a non-bear reference for that one?  I can only guess he is talking about vitamin B12 deficiency.  Unfortunately, there are still lots of vegans who are ignorant about supplementing B12.  Otherwise, there are some really good books out there on vegan nutrition for pregnancy and childhood if you want to learn about that.  As for the "skinny-fat" comment, many of the omnivores I know have terrible body composition, too, so I'm not sure where that gets us here.  Vegans have a lower BMI on average so at least they are less likely to have metabolic diseases.

De Vany then gets into some specious reasoning.  He says diabetes is increasing in places vegetarianism is practiced like India. Do you think this economist knows what a trend line might look like?  Does he think vegetarianism is new in India?  Does he think it is vegetarianism that is increasing there?  De Vany acknowledges obliquely that the people who have studied this trend toward diabetes are blaming Western foods, but he has a different belief.  It's the rice.

Rice GI values vary a lot by region.  Unless he can say the GI values of rice have been rising in these places I'm not sure he has much of an argument about this.

It's not quite right to call India vegetarian for these purposes.  Indians consume a lot of dairy and a lot of fat now.

This explains why vegetarian Indians have more body fat than non-vegetarians.  By the way, is De Vany saying that in a country where they consume high levels of dairy fat their children are not getting B12?

Dairy has plenty of B12.  Are we having a logical consistency problem here?

Amazingly, vegetarians in India are singled out here to have particularly low intakes of fiber.  This should tell you everything you need to know about the quality of their diets.

In any case, vegetarians are a minority of the Indian population, so blaming that for a rise in diabetes is chronologically and statistically a tough argument.

The grizzly bear citation is funny, but De Vany outdoes himself at the end of this section.  These three excerpts are from the same paragraph.  He starts out pretending to offer vegetarians diet advice, as though he has demonstrated mastery of the topic by this point.  He then turns full Rain Man.  "I eat a lot of meat.  Carnivores can love the environment, too."  How’s that for a non sequitur?  Carnivores can love the environment?  Who said they couldn't  love the environment? Would their emotions change their actual effect on the environment, though?  He finishes by recommending a restaurant in Utah for its boar sausage.  This in a paragraph that started as helpful advice for vegetarians.  I am amazed that a college professor wrote this.  I wonder if he graded anyone’s papers.

I'd like to address De Vany's statements on another topic as well.  Calorie restriction is a strategy under investigation for its potential to extend lifespan.  De Vany claims that his diet accomplishes what calorie restriction does because it restricts glucose.  Remember, his diet is very high in protein and I have already shown you that excess protein appears to shorten lifespan, not lengthen it, so he is misguided before he ever brings up glucose. He is making his argument about glucose in humans based on experiments in bacteria.  Really.

Slow down, Doctor.  Let's check it out in mice first.  In this study, we see De Vany's hypothesis is tested.  It turns out his idea is a bust.  The researchers reject glucose restriction.

De Vany bases this idea on a just-so story he seems to have made up himself.  According to him, a lot of glucose in the diet signals abundance to the brain, so the brain decides it is time to store fat.  So is the corollary that in cold weather the body will not try to store fat?  Why would that be good?  And why wouldn't any surplus energy be stored as fat, regardless of its source?  Does that make sense to you?  It doesn't to me.

Mammals generally develop fat storage patterns to assist in temperature regulation.  I don't see why early humans in cold climates would have benefited from low body fat stores.

Here's an alternative just-so story.  Think summertime.  An abundance of fruit and starch signals an abundant food supply.  Therefore, no fat storage is needed.  A diet with restricted carbs signals food scarcity.  Think winter.  Calories consumed as fat should be stored as fat until carbs are found. I think my story makes more sense than DeVany's.  How would DeVany explain the natural tendencies of the Eskimos, who had about as little carbohydrate as any population yet were often described as overweight.  This author observes that people in hot places weigh less than those in cold places.

As you can tell, I'm not impressed with the thinking De Vany put into his book.  I sincerely hope he is better with economics than nutrition.

The Eskimos are one of the model cultures for the Paleo belief system.  I'll look at some of those cultures in the Primitive Nutrition series.  But first, let's meet the man who brought our attention to these cultures, Weston Price.

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