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David Katz, M.D.

David Katz, M.D.

Posted: November 13, 2010 11:17 AM

I really can't recall the last time I crossed paths with a Twinkie. But this week, the Hostess snack cake made from 37 ingredients -- including sugar under at least three different names, partially hydrogenated oil (trans fat), and an array of artificial flavorings and colorings -- has collided directly into my plans to address another topic, which now must wait until next time. Today, we are stuck chewing on Twinkies.

Or, to be precise, the so-called "Twinkie Diet."

The storyline is pretty straightforward. An overweight nutrition professor at Kansas State University put himself on a predominantly snack food diet, with Twinkies prominent, for two months. He lost 27 lbs, and lowered his body mass index (BMI) from nearly 29, to just under 25 -- from almost obese to normal.

Compounding this ostensible assault on conventional nutrition wisdom were the effects of the diet on the professor's metabolic profile. His LDL cholesterol and triglycerides went down, while protective HDL cholesterol went up.

The voluminous and often titillating media coverage of this experiment might imply that it challenges what we know, or think we know, about nutrition and weight management. I write to refute that before it causes the body politic, or your body, any direct harm.

The most salient takeaway message from this N-of-1 experiment is a message I routinely deliver already: calories count. If the Twinkie diet results are disquieting for anyone, it's not those of us who generally espouse mainstream nutrition principles. Rather, it pretty emphatically rebuts claims in such works as Good Calories, Bad Calories by Gary Taubes, which suggests that the role of calories in weight is subordinate to the source of calories.

Calories are a unit of energy, and the relationship between matter and energy figures prominently among the physical laws of the universe. An aggregation of high quality science, and the gaps in that science, provide opportunities for nutritionists to debate and defend some competing theories and perspectives. But the laws of physics are not among them. They are not negotiable.

The Twinkie diet was a dreadful diet. But it was, nonetheless, a diet in the conventional sense, meaning it was calorie-restricted. The professor reduced his calorie intake from a maintenance level of roughly 2,600 kcal per day to less than 1,800 kcal for 10 weeks.

A deficit of roughly 3,500 kcal is required to lose one pound of body fat. A restriction of 800 kcal per day for 70 days represents a calorie deficit of 56,000 kcal. That would be enough to account for a loss of 16 pounds of body fat. It takes smaller calorie deficits to lose other body tissues -- such as muscle -- and none at all to lose body water, which tends to happen with dieting. Calorie restriction produced the professor's weight loss, and was not particularly helped -- and certainly not hindered -- by the fact that these were mostly "bad" calories.

As for the changes seen in the lipid panel, these are likely by-products of weight loss per se. An excess of body fat is associated with increased inflammatory responses, and often, increased levels of insulin. Both inflammation and hormonal imbalances in turn affect cholesterol and other blood lipids. When body fat is lost, these effects are reversed -- and improvements in blood lipids are likely.
The mistake is to think this means better health. For one thing, health is a composite of far more than BMI and LDL. For another, its relevant time horizon is far more distant than two months.

Severe illness of all kinds is associated with sudden drops in total cholesterol. Drug addiction, chemotherapy, cholera and advanced HIV are all associated with weight loss. Cancer rather predictably leads to declines in both weight and lipids as it advances. These associations are more than sufficient to show that health cannot be summed up by weight and lipids. An overwhelming body of research shows what dietary patterns do produce lasting good health -- all emphasize wholesome, mostly plant foods direct from nature. None emphasizes Ho Hos.

The two-month timeline here is important for another reason. Over the long term, controlling calories means either going hungry, or finding a way to feel full and satisfied on fewer calories. Here's where the quality of calories certainly does matter. Foods of high nutritional quality include, among their many virtues, the capacity to produce fullness on fewer calories. Eating until full and yet being lean is having your cake and eating it too -- but snack cakes will never get you there!

Chewing on implications of the Twinkie diet for health in the context of either science or sense reveals that calorie control for weight loss always was a good idea, and still is; chewing on Twinkies never was, and still isn't.

Dr. David L. Katz; www.davidkatzmd.com
www.turnthetidefoundation.org


 

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