Low-carbohydrate diets such as Atkins and the South Beach diet are based on a premise that is "so utterly wrong as to be insane," according to David L. Katz, MD, MPH, from the Yale Preventive Medicine Research Center in New Haven, Connecticut.

Dr. Katz, the author of The Way to Eat: A Six-Step Path to Lifelong Weight Control, is a nationally known nutrition expert and nutrition spokesperson for the American College of Preventive Medicine (ACPM). In a series of packed sessions here at Preventive Medicine 2004, the ACPM's annual meeting, Dr. Katz delivered stinging criticisms of the low-carb diet fad.

Along with other critics of low-carb/high-fat diets, Dr. Katz claimed the "tipping point in the fat wars" was a cover article in the New York Times Sunday Magazine that asked the question: "What if it's all been a big fat lie?" The article claimed that critics of the Atkins high-protein diet approach were wrong. The diet, according to author Gary Taubes, did result in weight loss without increasing cardiovascular risk.

But Dr. Katz maintains that any diet that doesn't follow a simple formula aimed at correcting energy imbalance, ie, more calories ingested than calories expended, will not stand the test of time. Moreover, he cautioned that the food industry is responding to the low-carb frenzy with a whole array of low carb products, "including low-carb marshmallows."

It is, Dr. Katz said, a case of history repeating itself. "Why don't low-fat diets work? Snackwells, that's the answer," he said, referring to a line of low-fat snack foods. He noted that as the food industry produces foods labeled low-fat or low-carb, Americans line up to eat them. "We eat more because we can. There are 3,800 calories produced in the U.S. every day for every man, woman, and child in America. We eat too much because there are too many calories available."

Moreover, he warned that using the glycemic index to select food — an approach recommended by the South Beach diet — will lead to ridiculous and sometimes comical choices. For example, ice cream has a lower glycemic index than carrots and carrots are lower than white parsnips.

Dr. Katz argued that physicians should not be "content with weight loss by any means."

But Lisa Sanders, MD, also from the Yale Preventive Medicine Research Center, said physicians should not summarily dismiss low-carb diets.

Looking at published studies, she said it is clear that "calories do count, but in the short-term, studies indicate that low-carb dieters lose more weight than low-fat dieters when eating the same calories." Moreover, she noted that claims by Atkins and South Beach proponents that the diets eliminate hunger may have some validity. "I think he's [Atkins] got something there," she said, noting that even though the diets don't limit calories, low-carb dieters tend to "eat less, suggesting that they are not hungry. So that is something to consider."

But Dr. Sanders said the long-term attrition rate among low-carb dieters is probably the same as among low-fat dieters.

The bottom line for clinicians, said Dr. Sanders, is that "there is a whole new world out here" that will require "physicians to reshape our practices to fit our patients and to fit the world we live in. Patients are using these [low-carb] diets. We need to work with that."

"Obesity is one of the biggest crises ever to confront the public health community," Dr. Harmon said. And the solution is not simple "and probably requires a multifaceted approach that is going to have to start with families and the feeding of young children."

Dr. Harmon added that it is difficult to fault weight loss — even if it is achieved by low-carb dieting — but he said the ACPM favors a long-term balanced diet and exercise approach rather than endorsing either low-carb or low-fat diets.

Source: Diabetes In Control.com: ACPM 2004: Session 33. Presented Feb. 21, 2004.

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