Meta-analysis: All Diets Essentially Equal
A study just published in JAMA (Journal of the American Medical Association) compared 48 studies assessing weight loss with popular named diets, such as Atkins, South Beach, Zone, Biggest Loser, Jenny Craig, Nutrisystem, Volumetrics, Weight Watchers, Ornish and Rosemary Conley. They found no clinically significant difference in weight loss among the various diets.
Low-carbohydrate diets averaged a loss of 8.73 kg at 6 months and 7.25 kg at 12-months, while low fat dieters lost 7.99 kg at 6 months and 7.27 kg at 12 months.
All diets restricted calories, typically to about 1,500 calories per day.
The results of this meta-analysis support what previous reviews of the literature have found: adjusting the proportion of macronutrients (fat, protein, carbohydrates) does not seem to be important for weight loss. All that matters is calorie reduction.
What is overwhelmingly more important than the type of diet is the ability to stick to the diet long term. The researchers therefore recommend choosing a diet that is sustainable – making permanent and acceptable changes to your diet rather than going on a temporary diet you find difficult.
It should also be noted that there are health concerns related to diet other than weight control. Eating a varied diet with plenty of fruits and vegetables is generally a good idea.