Research deemed to be the first 'controlled' trial of the Atkins Diet finds it may be as safe and effective as conventional diets.
The Atkins Diet, which limits carbohydrates but permits unrestricted amounts of protein and fat, has proved controversial among nutritionists who claim that people miss out on many nutrients gained in a balanced diet.
But in the new study, carried out at three US centres, Atkins dieters lost the same amount of weight over one year as a group following a high- carbohydrate, low-calorie approach. The Atkins dieters also had significantly greater increases in good cholesterol (HDL) and greater decreases in triglycerides than the conventional dieters.
The study, published today in the New England Journal of Medicine, investigated 63 obese men and women who were 44 years of age and weighed an average of 216 pounds. All participants met with a registered dietitian at the beginning of the study and at three, six and 12 months. Those in the Atkins group were given a copy of Dr. Atkins New Diet Revolution and asked to follow the diet as described. The conventional diet group was given instructional materials on a 1200-1500 calories/day (women) or 1500-1800 calories /day (men) diet that consisted of 60 per cent carbohydrate, 25 per cent fat, and 15 per cent protein. The researchers report that Atkins participants lost more weight at three, six and 12 months, than the control group. After one year, Atkins participants had greater increases in HDL cholesterol (18 per cent compared to 3 per cent) and triglycerides were reduced by 28 per cent, compared to only 1per cent in those following a conventional diet. Neither group showed changes in LDL (bad) cholesterol at one year ."Obesity is a national public health problem, and we need to evaluate alternative weight loss approaches aggressively. To widely recommend low carbohydrate approaches may be premature, but our initial findings suggest that such diets may not have the adverse effects that were anticipated," said study leader Dr Gary Foster, Associate Professor of Psychiatry and Clinical Director of the Weight and Eating Disorders Program at the University of Pennsylvania.
He added: "The real issue is whether low carbohydrate approaches help patients maintain their weight loss better than conventional approaches. It will also be important to determine whether the effects of the diet on cholesterol are the same during weight maintenance as they are they are during weight loss."
But he also cautioned that larger and longer studies are needed to assess the long-term safety and efficacy of low carbohydrate approaches. "These preliminary data suggest that weight losses will be comparable to conventional approaches over a 1-year period, but there may be some favorable effects of a low-carbohydrate approach in terms of triglycerides and HDL (good) cholesterol," Foster said.
Similar findings for a low-carbohydrate diet by another group of Penn faculty working at Philadelphia VA Medical Center were also reported in the journal. In their six-month study, Dr Frederick Samaha and colleagues found that a low-carbohydrate diet was associated with greater weight losses, reductions in triglycerides and improvements in insulin sensitivity compared to low-calorie, high-carbohydrate diet in 132 patients who were 53 years old and weighed 288 pounds.
Foster and his colleagues at the Washington University and the University of Colorado are currently enrolling participants for a large, NIH-funded, five-year study of low- and high-carbohydrate diets.
"This larger study of 360 participants will help us more fully assess the benefits and risks of low-carbohydrate diets on bone mass, kidney function, arterial function and exercise tolerance," Foster explained.