The Lancet has published a review of the data regarding low-carbohydrate diets, such as Atkins. Here are some conclusions:

Although these studies provide evidence that a low-carbohydrate diet does produce increased weight loss over 3-6 months and might be superior to the recommended calorie-reduced low-fat diet, the 12-month studies also indicate that the low-carbohydrate diet may be no better in the longer term.

The most frequent complaints with low-carbohydrate diets are constipation and headache . . . Also, halitosis, muscle cramps, diarrhoea, general weakness, and rashes are more often reported on low-carbohydrate than on low-fat diets.

And we have the bottom-line:

There is no clear evidence that Atkins-style diets are better than any others for helping people stay slim, and despite the popularity and apparent success of the Atkins diet, evidence in support of its use lags behind . . . the long-term effects on health and disease prevention are unknown.

So, what can physicians recommend? People who want to try Atkins should be told that although safety cannot be guaranteed, low-carbohydrate diets seem to be safe for short-term use (up to 6 months).

Based on the evidence, the most solid recommendation would be (not surprisingly) a permanent switch to a reduced fat and calorie diet in combination with increased physical activity. It may not sell as many books, but this approach certainly has the evidence to back it up.