A low-carbohydrate diet is more effective for weight loss and reducing cardiovascular risk factors than a low-fat diet, according to a new study.
To compare the effects of a low-carbohydrate versus a low-fat diet on body weight and cardiovascular risk factors, researchers randomly assigned 148 men and women without clinical cardiovascular disease and diabetes to follow a low-carbohydrate (less than 40g a day) or low-fat diet (less than 30 per cent of daily calories from fat).
All participants were classified as obese based on body mass index and just over half of the participants were black.
Both the low-carbohydrate and the low-fat groups received dietary counselling at regular intervals but had no specific calorie or energy goals.
At 3, 6, and 12 months, participants on the low-carbohydrate diet had lost more weight than those on the low-fat diet.
At 12 months, those in the low-carbohydrate group had lost an average of 7.7 pounds (3.5 kg) more than those in the low-fat group.
Although participants in the low-fat group had a greater reduction in their waist size at 3 and 6 months, there was no difference at 12 months.
Overall, blood levels of certain fats that are predictors of risk for cardiovascular disease also decreased more in the low-carbohydrate group.
Physical activity was similar in the groups throughout the study, suggesting that the greater weight loss among participants in the low-carbohydrate group was not because they exercised more.
When the researchers evaluated the black and white participants separately, the results were similar.
The study was published in the journal Annals of Internal Medicine.