Hypothesis #1: Carbohydrates

In my first post I tried to make the case that generally a paleo/primal diet must be if not optimal, at least safe - probably the safest possible diet.

Now I'm going to spend a few posts on the primary hypotheses for the causes of the diseases of modern civilization. First up is the Carbohydrate Hypothesis.

From a macronutrient perspective the biggest change from the paleolithic to the neolithic is the addition of huge quantities of carbohydrates. Carbohydrates are not an essential macronutrient (you can eat zero of them and be just fine) and most sources of significant carbohydrates are not nutritionally dense (they don't have a lot of vitamins), so you lose nothing by cutting them out. In paleolithic man the main organ that regulated blood sugar was the liver, which manufactures glucose. In modern man it is almost exclusively the pancreas that regulates blood sugar, which responds to dietary carbohydrate (glucose) by releasing insulin into the bloodstream. The liver exerts a very fine control, but the pancreas exerts at best a very coarse control that results in sugar spikes and crashes. This ultimately leads to a screwed up metabolism where your insulin sensitivities are shot and all kinds of bad stuff occurs, often starting with obesity. There are links that can be made to many of the modern diseases using modern scientific evidence (e.g. cancer cells only grow in the presence of glucose). The worst offenders are probably the most refined carbohydrates in the form of white flour and refined sugar. This argument is best stated by Gary Taubes in his books, Why We Get Fat and What To Do About It and Good Calories, Bad Calories.

OK, so that is the statement of the hypothesis, but what do I think of it? Well, there is a reason that I am talking about this hypothesis first: I think it is critically important to talk about carbohydrates whether or not this is the true root cause of obesity and other diseases of civilization, because a low carb diet is almost certainly a useful medical intervention once your metabolism is screwed up. A huge fraction of Americans have a screwed up metabolism and if you are fat you are one of them (us). Overall I find the hypothesis very compelling, so I have not just adopted a paleo diet, but a fairly low carb paleo diet (avoiding potatoes, sweet potatoes, bananas, and grapes and the like).

Notice that if this hypothesis is true, a paleo diet easily avoids the harmful carbs.

Other potentially interesting carbohydrate hypothesis links:

• Gary Taubes' books do a fantastic job of explaining why conventional nutritional wisdom is wrong. Really wrong. But this lecture by David Diamond, Ph.D. is also great.
• This lecture is about the A-Z diet study. It was one of the first clinical trials to show the effectiveness of low carb diets.
• Go watch Tom Naughton's Fat Head video. You can stream it from Netflix or order a DVD from his site.
• The Ancestral Health Symposium just happened. Check out the talk by Dr. Michael Eades (who wrote Protein Power and other books on carbohydrate restriction). In the talk he tries to make the case for lower carbs in the context of paleo.
• The book New Atkins For a New You is excellent and contains a ton of really useful specific advice for watching carbs (although it is most assuredly not "paleo").
• Jimmy Moore has a great popular podcast, Livin' La Vida Low Carb.
• Dr. Robert Su has a medically oriented podcast and blog that is quite good (and a book that I just ordered).
• Here's a talk that Gary Taubes did at the invitation of Rivendell Bicycle Works (I own a Rivendell - Yay! Awesome bike.) There is other Gary Taubes stuff on YouTube too if you poke around a bit.

The Case For Paleo

There are a lot of reasons that people try a paleo/primal diet. But I think one reason trumps them all.

It is (theoretically) the safest possible human diet.

If you have any health condition that might be in part mediated by diet, maybe you should consider trying a paleo diet (including obesity, most people's reason for changing their eating).

There are several nutritional hypotheses for the diseases of civilization and I'll talk more about them in future posts. Almost all of the chronic diseases that we take for granted now (heart disease, cancer, gout, asthma, myopia, Alzheimer's, dental carries, gum disease, seasonal allergies, obesity, diabetes, and on and on and on), either are very rare or do not exist at all in hunter gatherer societies that have been studied. What is more is that this is almost certainly not genetic as the diseases appear very quickly when these peoples adopt a modern lifestyle. People have looked extremely hard for a causative agent, but it is possible to more or less rule out environmental factors like chemical exposures and the like.

So the most likely culprit is somehow the change in diet.

Let's start with the "Paleolithic Diet" (paleo) concept first. Anthropologists know that health significantly suffered with the transition to the neolithic (the introduction of agriculture) and in modern times we have a litany of diseases that we think may be nutritionally mediated. Humans evolved over millions of years to eat a diet much like paleolithic people must have eaten and we must be optimally adapted to such a diet. There has not been enough time on an evolutionary scale to adapt to a neolithic diet completely since we have only been farming for thousands of years. We do not know exactly what paleolithic diets looked like, but we know they must have been extremely varied and we can make a guess that modern hunter gatherer diets are an excellent indicator. All known hunter gatherer diets contain meat in some form, so it must be safe for humans to eat meat. Most of them contain vegetables (green leafy and root), so these in general must be safe as well. In climates where fruit is available it is also consumed, though the quantities can vary from none to small seasonal amounts to year round availability in the tropics. Grains, legumes, and pretty much anything else that needs to be cooked to be safe to eat or edible/palatable (when fresh - not talking about meat here) are not regular staples. Milk products are also non-existent past infancy in the vast majority of cases (there are herders that are exceptions to this).

So the argument for the paleo diet is, you can't go wrong if you eat meat, vegetables, and rational amounts of fruit and nothing else. This diet must be the safest possible human diet and it contains 100% of the macro and micronutrients that humans require. If you believe in moderation in all things, the paleo diet is the very definition of moderate around which you should vary things. Modern diets are very far removed from this and making small alterations to a modern diet in the hopes that you will guess the agents that cause modern disease is a very bad bet indeed - you are statistically destined to fail in the absence of a whole bunch of nutritional data that does not exist.

I have been eating a paleo diet for months now, modified with some dairy because I believe that it is probably safe for me and I have no milk tolerance issues of any kind, but I'm keeping the associated carbs low (I'm eating mostly cultured dairy and high fat dairy). Plus wine, whisky, soy sauce, and occasional very small cheats, including some peanuts and half a hamburger bun here and there. I am not eating potatoes or sweet potatoes or bananas or grapes, all of which are "paleo", but high carb.

I have gone from tipping into the obese category (270 pounds and 28% body fat) to 215 pounds 18% body fat* (so far), so it certainly worked for me. It has also had a ton of ancillary benefits that are obvious. And maybe some that aren't so obvious, but will help me live longer and healthier.

I'm more than halfway convinced that this is the fountain of youth. Come take a drink.

David

* - Measured by impedance. It might not be super accurate, but you can definitely see that it changed.