The results of two studies published in the Annals of Internal Medicine (vol 140) pp 769-777 and 778-785 will again raise nutritionists' fears that low-carb, high-protein diets could cause kidney problems and impact bone growth and regeneration.
But the studies seem to contradict numerous studies that have clearly defined a link with a high-fat diet, particularly one that is high in saturated fat, to increased cholesterol levels.
The first study, carried out at Duke University Medical Center, took 120 obese adults and assigned them to either a low-carbohydrate diet, or a conventional diet (restricting caloric intake to 500 calories per day with less than 30 per cent of calories from fat).
After six months, the people on the Atkins-style diet had lost an average of 26 pounds, compared to an average of 14 pounds in the conventional low-fat diet group. Cholesterol levels also improved more on a low-carb diet compared to a low-fat diet.
The second study also yielded similar results, as scientists from the University of Pennsylvania Medical Centre subjected 132 obese adults to either a low-carbohydrate diet or low-fat experimental groups. The study found that after six months the subjects on the low-carbohydrate diet lost the most weight and had improved fat levels. However, at 12 months both groups had lost similar amounts of weight.
The low-fat group continued to lose weight from six to 12 months while the average weight in the low-carbohydrate group had remained steady after six months.
The study was quick to point out that the findings were limited by a high drop-out rate (34 per cent) and the strictness to which participants stuck to the dietary regime.
In the US there are currenly 30 million people following the Atkins plan or some sort of diet that restricts carbohydrate intake. The emphasis on replacing one of the main food groups while substantially increasing another has some nutritionists worried however. The new studies seem to suggest that not only does a low-carb diet work but there also seems to be additional health benefits.
The long term implications of subscribing to this diet regime have yet to be discovered as is the safety of following this plan in high-risk patients - such as in individuals with renal and kidney problems.
However with 65 per cent of US adults either overweight or obese, many will be tempted by the apparent success rate of the Atkins-type diets.