Assessing Low-Carb Diets

Low-carb diets are all the rage these days, but are they really effective over the long-term? And even if they are, are they really healthy?

Those questions are addressed in an article in the issue of The Lancet. Author Arne Astrup and colleagues from Denmark looked at studies comparing low-carbohydrate diets, such as the Atkins diet, with more traditional diets aimed at helping people lose weight. They also studied the way low-carb diets affect the body and potential problems resulting from a lack of nutrients from fruits, vegetables and whole grains.

In terms of previous research comparing diets, the authors note three major studies have shown varying results. Two studies comparing low-carb diets to traditional diets found people on these diets lost more weight at first, but after a year results were about the same. A third study found women on low-carb diets were more likely to come out ahead after six months than those on a traditional diet.

When it comes to the impact of a low-carb diet on the body, the authors explain restricted intake of fruits, vegetables, and whole grain breads and cereals could set people up for health problems because all these foods contain important nutrients proven to play a role in preventing heart disease and other conditions. They also note people on low-carb diets often experience unwanted side effects, such as diarrhea, rashes, general weakness, and muscle cramping.

According to Astrup and colleagues, the Atkins book claims weight loss occurs from increased energy expenditure. They believe the real reason may simply be people actually eat less due to the severe restriction of food choices, along with the fact that proteins, which are consumed more often in this diet, make people feel full faster.

The authors believe more study is needed before these diets can truly be recommended as a healthy way to lose weight. They conclude, “Although the diet appears, as claimed, to promote weight loss without hunger, at least in the short term, the long-term effects on health and disease prevention are unknown.”

SOURCE: The Lancet, 2004;364:897-899