Adherents of high-protein/low-or no-carbohydrate diets have, to some extent, hijacked the discussion of whether we should still be eating carbohydrates. Indeed, for some militant followers, carbs are seen as leading only to brain and body decay, and are to be avoided at all costs. Well, maybe it is time to reconsider this attitude.

Avoiding carbohydrates seemed like the logical response to poor insulin activity. Obesity often causes a decreased responsiveness to insulin and may result in Type 2 diabetes. But before the diabetes is confirmed, there are signs that the body requires more than normal amounts of insulin to push glucose in the cells. This is called insulin resistance or decreased insulin activity. “Well,” say the high-protein folk, “stop eating carbohydrates! No carbs, no glucose? No problem getting the glucose into your cells.”

What these high-protein adherents fail to mention is that the body can make its own glucose and only by following an exceedingly stringent no-carbohydrate diet does the body switch from its natural use of glucose to using fat for energy.  There are many side effects that come with a fat- burning (ketotic) diet:  dreadful breath, foggy brains and bad moods. But so what if one’s breath will kill mosquitoes? It is worth it so one does not have to worry about insulin and carbohydrates?  Eliminating fruits, vegetables, fiber, and dairy products, in short the foods that our bodies require for their nutrient contents, on such diet shouldn’t be a problem according to the non-carbohydrate folk.  Just take lots and lots of vitamin/mineral/fiber supplements.

There was only one problem with this approach. It apparently did not work.

A few weeks ago, researchers from Washington University in St. Louis published a study that is challenging the relationship between high protein and better insulin responsiveness. Bettina Mittendorfer and her colleagues divided 34 obese post-menopausal women into three groups: a non-dieting group, a dieting group that ate only the recommended daily amount of protein, and a third dieting group who followed a high-protein diet.

If the ‘high protein diet to improve insulin sensitivity’ proponents were correct, the women on the high protein diet should have shown the most benefit. They didn’t. In fact, there was no improvement among this group. Only the group whose diet contained carbohydrate showed improvement in insulin sensitivity; it increased by about 25-30%. And a side benefit assumed to be conferred by eating lots of protein while on a diet, i.e., no muscle loss? This did not happen either.

This study generated headlines, albeit brief about these unexpected results. However, Sargrad, Mozzoli and Boden reported similar results in the April 2005 journal American Dietetic Association. They found no improvement in fasting glucose levels or insulin sensitivity among dieters on a high-protein diet. Those on a high-carbohydrate diet did improve.

The absence of improvement of insulin sensitivity among the obese women on a high-protein diet is worrisome because they are already at risk for developing Type 2 diabetes. To bring glucose levels in the blood to normal levels, their beta cells in the pancreas have to produce abnormally high levels of insulin. Eventually diabetes can result.

What is also worrisome is that blunted insulin response affects the ability of a critical amino acid, tryptophan, to get into the brain. Tryptophan is the essential component of serotonin; too little or too inactive serotonin may result in depression, anxiety, inability to focus, or even fatigue. Insulin removes other amino acids from the blood that interfere with the ability of tryptophan to get into the brain. High-protein diets fill the blood with these interfering amino acids so that with such a diet, tryptophan levels in the brain may be lower than normal. Consequently, serotonin levels are lower. This may be one reason why there is a strong relationship between diabetes and depression.

The results of the Washington University study seem unfair. High-protein diets are no fun. The dieter can’t eat starchy carbs like popcorn, rice, or bread and must limit fruits and starchy vegetables like winter squash or potatoes. But this deprivation seems worthwhile if the result was an improvement in insulin sensitivity. But of course this did not happen.

The better option it seems is the natural one: Eat the amount of protein that corresponds to what the body needs but no more. Eat a variety of healthy fruits, vegetables, grains, and low-fat dairy products. And finally do physical activity, which in itself helps insulin shunt glucose into the cells so the body can use it for energy.

Not terribly exciting, nor the focus of television health talk shows or dinner table conversation....But it works.

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