Tuesday, July 23, 2013

What to Eat? Going by the Textbook

"Out with the old spiritual mumbo jumbo, the superstitions, and the backward ways. We're gonna see a brave new world where they run everybody a wire and hook us all up to a grid. Yes, sir, a veritable age of reason." -Ulysses McGill, O Brother, Where Art Thou?

If only. Eighty years after the Tennessee Valley was put on the grid, health gurus recommend mumbo-jumbo like two-thirds of a cup of sugar a day for diabetics,* inflammatory foods like wheat for the inflamed, and a low-fat, high-fiber, grain-based diet that fattens up livestock (in weeks!)** but is supposed to make humans slim and trim. The crazies are running the asylum. Are there any reasonable people in the mainstream?

I recently sent a friend of mine the book It Starts with Food. It discusses the major hormones involved in fat storage, fat burning and inflammation, along with the authors' dietary recommendations based mostly on our paleolithic ancestors' diets and their clinical experience. All their advice sounds right to me, but I know my friend is going to be skeptical about ditching the grains and beans and eating a lot of fat. To that end, following the lead of Dr. Eades, I checked some of the major tenets in the book with endocrinology textbooks available in Google Books. Where I'm writing "check," that means that the fact checked out with an endocrinology textbook.

  • Insulin is a hormone that is released to put blood glucose into cells. Check.
  • Consuming carbohydrate raises your blood glucose level. Check.
  • Cells can become insulin resistant, which prevents glucose from entering the cells. Check.
  • Your body then produces extra insulin to force glucose into the cells. Check.
  • Glucagon raises blood sugar levels when they're too low. Check.
  • High insulin levels prevent glucagon from acting. Check. 
  • Leptin is a hormone that signals satiety. Check.
  • Cells can become leptin resistant, preventing satiety signals. Check.
  • Leptin resistance is related to insulin resistance. Check.

In plain English, too much carbohydrate can make you fat and diabetic. It can also distort your appetite and possibly give you hypoglycemia. This isn't opinion, theory, or part of a fad diet, this is straight out of endocrinology textbooks.

Let's look at their paleolithic principles. The authors recommend meat (preferably pasture-raised), vegetables, fruit, animal fat (must be pasture-raised), natural plant fats, and limited nuts. They discourage grains, legumes, sweeteners, seed oils, hydrogenated oils, and dairy except butter. With the exception of butter, this is probably similar to how our ancestors ate for two and a half million years. I base this statement on books written by paleoanthropologists such as Richard Leakey, Alan Walker, Brian Fagan, Peter Ungar, and Loren Cordain. Except for Dr. Cordain, none of these authors promotes any diet that I know of. I've written about evolutionary diets here and here, and the bunkum of the "science" of vegan diets here and here. The short answer is that we've been eating meat as a substantial part of our diet for over two million years. We're pretty sure of this because of the evidence of stone tools, cut marks on animal bones, isotope analysis of our ancestors' bones, and the small gut size of Homo erectus. That our ancestors dispersed and became thin on the ground and rapidly developed big brains point to their being predators, not lotus eaters. I don't think there's any controversy over the notion that grains, dairy and beans are not paleolithic.

Despite this probably being close to our native diet, some of the recommendations are controversial. However, they have to be taken in context. The authors concede that a high-fat diet is inflammatory in the context of a high-carb diet. (I can attest that a high-fat, high-carb meal is hard on my stomach.)  Toxins are stored in animal fat, but pasture-raised animals have far fewer toxins. Some people have problems with low-carb diets, but you have to eat sufficient fat and give yourself time to adapt to the diet. Clogged arteries are full of cholesterol, but your body makes most of your cholesterol. (Check--it's in an endo textbook.) Cutting out dairy means cutting out a calcium source--but some vegetables have calcium and bone health depends on other vitamins and minerals as well as calcium.

I doubt these details are in any endocrinology textbook; however, there have been some clinical studies on paleo and low-carb diets showing favorable results.

As to the efficacy of the diet, the authors rely on their clinical experience with thousands of people. Their diet is very close to what I follow, and my own experience is that I take no medications, have a normal weight, normal lipids, good complexion, no tooth decay, no allergy symptoms, no GI problems, good sleep, and good energy. In the end, you should do what works. As my thermodynamics instructor said, "Concepts are fine, but if you can't get the right answer, you're no use to anyone."

*A person with normal blood glucose has about a teaspoon of glucose in the entire bloodstream.
**The cattle ate a bunch of oatmeal. Sure, it fattened them up, but just think of how they lowered their cholesterol.

Click here for Part II.

2 comments:

Carole Sampson said...

Excellent post, Lori!

Lori Miller said...

Thanks, Carole.