Sunday, September 18, 2011

Hypothesis #5: Processed Foods

Hypotheses of modern disease, stop number 5: processed foods are killing us. We need to eat more in accord with Nature.

OK, I admit that this is the least scientific of the hypotheses that we have discussed so far, but it is by far the most prevalent. Some people become vegetarians for this reason. Some start eating organic produce. Some become locovores. Some join the whole food movement. Some just cut back on "cured" meats (I have an issue with this one, but that will have to be a different post).

It is understandable. In a country where it is difficult to buy heavy cream whose ingredients are, "Cream" and it is perfectly legal to list, "Orange Juice" as the only ingredient in a laboratory derived cocktail, processed foods comprise the vast majority of available foodstuffs. The vast majority of this vast majority of processed foods contains wheat and/or sugar.

There are a lot of differing opinions about exactly what it is in these frankenfoods that is bad for us. But we don't have to know the right answer if we can just avoid them entirely. A paleo diet lends itself to processed food avoidance pretty well. Eat your meat. Eat your veggies. Leave the frankenfoods for someone else.

Hypothesis #4: Antinutrient/Irritant

Our next stop on the hypotheses of modern disease train is the Antinutrient/Irritant Hypothesis. It goes like this...

Many plants produce organic defense compounds to make it less likely that they will be eaten. Some are much less obvious about it than, say, poison ivy. Grains and legumes in particular contain classes of compounds that are antinutrients (prevent the absorption of nutrients) or irritants. The most well known examples are the compound in peanuts that causes a severe allergic response in some people and the gluten in wheat which is a major problem for those with celiac or other sensitivities. But all grains and legumes have similar compounds. These obviously cause many problems for those with sensitivities (milk too for adults who are sensitive), but they could easily also be causing problems for the population at large, or low level sensitivities could be much more common than people think. It would be smart to avoid consuming all plants that contain defense compounds if they are not part of the diet that humans have evolved to eat. People with gut issues will usually see an improvement with a paleo diet and this is why. This hypothesis is best stated by Robb Wolf in the book Paleo Solution. The Wheat Hypothesis is really a special case of the Antinutrient/Irritant Hypothesis.

What do I think? Could be true. As someone without any particular sensitivities to food (but who got obese and had high cholesterol and some minor examples of modern disease - carries, gum disease, acid reflux, elevated blood pressure, etc) it isn't super compelling for those things (well, maybe acid reflux). You can craft really compelling theories that explain autoimmune disorders and inflammatory disease, but the biochemistry isn't as compelling for obesity and metabolic syndrome. Although what kills you in metabolic disease is most assuredly inflammatory effects.

Once again, though, notice that if it is true, a paleo diet protects you.

Friday, September 9, 2011

Hypothesis #3: Wheat

A quick recap: we've talked about the case for paleo, the Carbohydrate Hypothesis, and the Fructose Hypothesis.

Next up I'm going to look at the Wheat Hypothesis. This one is something I've been thinking about primarily because I recently read Wheat Belly by William Davis - so this will be part exploration of the hypothesis and part book review. The hypothesis goes like this:

Modern wheat is a carefully hybridized variant that is genetically very different from the wheat of even 50 years ago. The Western world simultaneously started consuming more wheat and changed the very nature of the wheat itself with disastrous consequences. Currently more than 99% of the wheat in our food is one of these adapted varieties. They have more and more harmful gluten compounds that impact everyone not just those with celiac disease and that are literally chemically addictive. The carbohydrate hypothesis is also true, but notice that the vast majority of carbs consumed are in the form of wheat so it is almost meaningless to talk about reducing carbs in general - it makes much more sense to focus on wheat. The form of carbs in wheat are also especially easily converted into glucose resulting in much worse blood sugar management than other carb sources.

What do I think? It will be very hard to distinguish between the Wheat Hypothesis and the Carbohydrate Hypothesis without some very carefully controlled experiments. It is true that anyone who cuts back on carbs is probably also cutting back on wheat. It is also true that anyone who cuts back on wheat is cutting back on carbs. But it certainly could be true that wheat alone is responsible for many modern ills. If true it would handily explain why some people see remarkable results on a high carb variation of a paleo diet (I suspect mostly non-obese people).

Notice once again that a paleo diet (especially one low in carbs) has you covered.

Now the book review. Wheat Belly is a great book. I learned a lot about wheat from it. It is the perfect book to hand to someone who simply can not let go of the idea that whole grains are healthy. Although Dr. Davis focuses on wheat, his dietary recommendations are more comprehensive than that and are quite sensible. In fact his actual diet advice is very nearly Primal. Although I do take issue with a few of his recommendations (Fruit juice? Really?) I mostly agree with him and mostly follow that diet myself.

However a review of this book wouldn't be complete if I didn't point out that the Kindle edition has a TON of typos that should have been caught by a spell checker. Apart from typos it is fairly well edited, but these are annoying.

Saturday, September 3, 2011

Hypothesis #2: Fructose

OK, we've talked about the general case for paleo and the carbohydrate hypothesis. Next up is the fructose hypothesis.

All carbs are not created equal. The single biggest change to the modern American diet is the vast quantity of sugar that we consume, mostly in the form of sucrose and high fructose corn syrup (which are pretty interchangeable from a dietary standpoint). The amount of fructose thus consumed is unprecedented in human history. Fructose is metabolized differently from other monosaccharides and it is especially able to cause leptin sensitivity issues, which can lead to obesity and insulin sensitivities as well (metabolic syndrome and diabetes). You can find populations that eat a lot of carbs, but do not have obesity, diabetes, and breast cancer (the Japanese) - the main dietary difference seems to be the amount of sugar consumed. The leading proponent of this hypothesis is Robert Lustig, who has a hit YouTube video and a talk at the Ancestral Health Symposium (AHS). He has convinced (I think) Gary Taubes that this idea has merit and Taubes has written an excellent article on it and discussed it at the recent AHS.

What do I think? The idea certainly has merit. I know fat people who don't consume that much sugar and sugar addicts who aren't fat, so the story probably isn't quite that simple. We really do consume an appalling amount of sugar and it is pretty easy to blame at least some of the modern ills on sugar (gout and more). It seems quite plausible that fructose is responsible for the obesity epidemic. Cutting out fructose is probably not enough to make you skinny if your metabolism is screwed up and it probably is. But maybe cutting way back could prevent our children from suffering the same fate.

Notice again that a paleo diet protects you completely if this hypothesis is true.

Thursday, September 1, 2011

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.