Friday, July 10, 2009

Walter Willett

Hypoglycemia had its icy fingers around my neck, back when I was starting graduate school. I was trying to eat well, with a breakfast of oatmeal. But somehow by lunch I could barely crawl out to the row of lunch trucks along 33rd St. Desperate, I called my Mom, who recommended Let's Eat Right To Keep Fit by Adele Davis. Thanks, Mom! I switched to wheat germ - now that's a substantial breakfast!

Some years later, my pleasant Saturday routine was breakfast in New Paltz followed by a hike along the Millbrook Ridge trail. That regular repetition provided a good laboratory, a way to isolate which causes led to which effects. A plain cheese omelet would have me rooting through my backpack for the rice cakes, out around mile four. A cheese omelet with broccoli and the rice cakes made it home untouched. But there's practically no nutrition in broccoli! Vitamins and minerals, sure, but that's not going to influence digestion or blood sugar, not over the course of an hour or two. Ah, fiber!

Another experiment - explore the oat spectrum, from quick oats to rolled oats, steel cut oats, whole oat groats. Groats take forever to cook, but I have never found a more solid nutritional foundation for a day. The key, at least for my system, is to eat food that digests slowly, so it keeps generating energy over hours instead of mere minutes. There are some people for whom the challenge seems to be to speed the process up so things don't sit for days. One size doesn't fit all!

My current diet bible is Walter Willett's Eat, Drink, and Be Healthy. He corrects two major over-simplifications to the standard food pyramid. Fats and oils need to be divided - trans fats should be avoided altogether, saturated fats limited, but mono- and poly-unsaturated fats can be eaten in practically unlimited quantity. Similarly, refined carbohydrates need to be limited, while whole grains are a good foundation for a diet. Willett mentions a spectrum of whole wheat flours, from finely ground to coarsely ground. This is like rolled oats versus steel cut oats. It's not just the balance of chemical constituents that matters, but the larger scale structures into which the molecules are organized.

What puts Willett's book into a class of its own is not its discussion of the properties of various foods, but its description of the scientific methods used to discover those properties. He describes laboratory studies with animal subjects and clinical trials with human subjects. But he also discusses the lifecycle of scientfic knowledge, the unreliability of the latest research reports and how further study of a subject slowly sifts out the various erroneous hypotheses. It usually takes decades to work out the kinks. By the time a topic gets to the college textbooks, it's usually reliable enough for routine application - but then it is long out of the news. Nutritional science in the news and nutritional science to eat by are two very different beasts!

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