Sunday, February 12, 2012

The Nutrition Debate #40: What are “Safe Starches”?

If you think this is a column about the Glycemic Index, you are wrong. If you think this is about “complex carbohydrates” vs. “simple sugars and refined carbohydrates,” you are wrong. Those are comparisons that you might make if you thought you had a state-of-the-art view of changes in the diet that lower glucose spikes. Spikes are temporary but they become chronic elevations in blood sugar that are harmful, leading to insulin resistance, overweight, neuropathy, Metabolic Syndrome, etc. As insulin resistance gets worse, you develop Type 2 diabetes or worse….such as Alzheimer’s.

Eating complex carbs will have an incremental benefit in such cases, but that is not what is meant by “safe starches” in the debate that is raging in the higher circles of erudition in the nutrition blogosphere. It is a newer idea and a very controversial one that has divided some of the stars in that firmament. The issue as I see it is as follows:

On one side of the debate is Gary Taubes and his many acolytes, both the highly erudite and ordinary hackers like me. Taubes is a highly respected science writer, blogger, and the author of “What if It’s All Been a Big Fat Lie?,” the seminal cover story in the NYT Sunday Magazine on July 7, 2002. His 2007 tome, “Good Calories – Bad Calories,” targeted to physicians, is the “bible” for an increasing number of young clinical practitioners and researchers. His more recent book, “Why We Get Fat and What to Do About It” (Deckle Edge, 2010), was written for the general public.

Taubes theorem is that obesity is caused by a metabolic dysfunction in which insulin resistance, developed from eating too many simple sugars and refined carbohydrates, leads to high levels of circulating (serum) insulin, which leads to fat synthesis (lipolysis), and declining function of the pancreas (where the insulin is produced) as its beta cells wear out and die. For such people, a diet based on a low-carb, ketogenic way of eating, is therapeutic. I am in accord with this view.

The “safe starches” debate arose when researchers sought a “perfect health” diet for health maintenance. Obesity and Metabolic Syndrome, Type 2 diabetes and dyslipidemia (high cholesterol) have all seen dramatic increases over the last fifty years since we began eating low-fat and, as a consequence, high carb. So researchers examined diets for many indigenous populations in the world who have not developed the Diseases of Civilization (CHD and CVD, stroke, many cancers, and Alzheimer’s). These people eat starches as whole foods, without vegetable oils, as a staple of their diet.

These researchers found that certain carbohydrates, what they are calling “safe starches,” can be eaten in reasonable amounts (10% to 30%, by calorie) by people whose metabolic function has not been compromised by insulin resistance. Compare this to the 60% (300 grams or 1,200 calories a day on 2,000 calories) that is the recommended amount of carbohydrates in the Standard American Diet. Incredible as it sounds, that’s right. If you doubt this, check the Nutrition Facts Panel on any packaged food and do the math yourself. These “safe starches” people (those who can eat them) are most likely to be people who are not already overweight as a consequence of their insulin resistance. To be clear, if you are already overweight, you probably have insulin resistance, and you cannot safely eat these ‘safe starches’ (or any other starches or sugars) without harmful, prolonged high blood sugars, ultimately damaging your general health.

For those who can eat them, what are these “safe starches”? Paul Jaminet, Ph. D., in his Perfect Health Diet,” both book and blog, lists sweet potatoes, potatoes, plantains, taro and others. Kurt Harris, M. D., of the Archevore blog, adds yams and bananas. They both include white rice, a grain. Harris says, “Except for white rice, these are all whole food starch sources with good mineral and micronutrient content that have been eaten in good health for thousands of years in many environments by genetically diverse populations. Many of these plants have spread far from their biomes of origin and serve as staples for populations who have adopted them with success over the past few thousand years.”

“White rice is kind of a special case. It lacks the nutrients of root vegetables and starchy fruits like plantain and banana, but is good in reasonable quantities, as it is a very benign grain that is easy to digest and gluten free.”

So there you are. If you’re healthy and not overweight, you can eat “safe starches” guilt-free and (almost) to your heart’s content. And don’t forget the butter and sour cream on that baked potato. Note that I did not say French fried potato. In two weeks, I’ll explain why there’s a difference. Next week the subject is “Unsafe Starches and Other Sugars.”

© Dan Brown 2/12/12

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