If you have been reading the newspaper recently, you will have come across some startling new nutrition advice. A much hyped new study, conducted with just 150 participants, calls for us to “embrace fat”—even the saturated kind. The alleged benefits? Weight loss and, most incredibly, healthier hearts.
Unfortunately, this media attention is much ado about nothing.
Low-carb diets have been advocated by various “experts” for at least 225 years. Many sources credit John Rollo with being the first to promote a low carbohydrate diet for diabetics in the late 1700s. In the 1860s, an English undertaker by the name of Banting published his famous “Letter on Corpulence, Addressed to the Public.” His diet, which advocated giving up several starchy foods, was so popular that for decades dieting was actually called “Banting.”
James Salisbury, the 19th century American physician and food faddist, promoted the steak he named for himself as part of a high-meat diet in 1888. Since then, the number of promoters for this dietary approach has been endless. I recall my mother eating cottage cheese in order to lose weight when I was growing up in the 60s, because of diet books written by doctors with nothing but theory to back them up. Probably the most famous of all is Robert Atkins, whose book Dr. Atkins Diet Revolution, published in the mid 1960s, is still a bestseller.
In the two centuries during which these diets have been promoted, there have been hundreds of studies comparing low-carb to low-fat diets. One would think that by now it would be clear which was superior if there really was a difference. But if you take all of these diet studies, and analyze the enormous body of data they produced, there is no proven difference between them as far as weight loss is concerned. In fact, another such analysis was published the day after the over-hyped low-carb study with this same conclusion.
More to the point, however, is that this most recent study really did not actually prove that low-carb diets are superior. The low-fat diet in the study was not that low in fat, and the low-carb group ate significantly fewer calories. If anything, the study only confirms that fewer calories result in more weight loss.
Moreover, the study provided intensive dietary counseling, not available to most people, and only followed participants for a year. Everyone who knows anything about weight loss knows that as soon as a diet ends, the pounds go right back on. Indeed, studies show that only 15 to 25 percent of those who lose weight are then able to keep it off.
I honestly have no opinion as to whether altering the fat or carbs in your diet is the best way to lose weight, and I am considered an expert in nutrition. Of course, it is possible that this current study may, in fact, herald the breakthrough that we’ve all been waiting for. But there would need to be many more studies to confirm these findings before we lay to rest this centuries-long debate.
* David S. Seres, MD is Associate Professor of Medicine in the Institute of Human Nutrition, and member of the Clinical Ethics Committee at Columbia University College of Physicians and Surgeons. He is a Public Voices Fellow with the Op-Ed Project and this year’s recipient of the Excellence in Nutrition Education Award from the American Society for Nutrition.
The opinion expressed is his.