Low-fat diet beats low-carb

1st March 2010 - A low-carb diet may offer quick results, but a new study suggests that a low-fat diet may be best for long-term weight loss and maintaining a healthy weight.

US researchers found that obese people who followed a low-fat diet may be more likely to keep the weight off three years after starting the diet than those who followed a low-carbohydrate diet.

"Although participants in the low-carbohydrate group lost more weight at 12 months, they regained more weight during the next 24 months," writes researcher Dr Marion Vetter from the Hospital of the University of Pennsylvania and colleagues in the Annals of Internal Medicine. "In contrast, participants in the low-fat group maintained their weight loss."

The study

In the study, researchers started with a group of 132 obese people who weighed an average of 130.9 kilos (289 pounds) before starting either a low-fat diet, a calorie-restricted diet with less than 30% of daily calories from fat, or a low-carb diet with fewer than 30 grams of carbohydrate per day for 12 months.

After six months on the diets, the group on the low-carb diet experienced the greatest weight loss, but by 12 months there was no significant difference in weight loss between the two groups.
Three years after the study began, and two years after the diets ended, researchers followed up with 40 people in the low-carb diet group and 48 in the low-fat diet group.
They found people in the low-carb diet group weighed an average of 2.2 kilos (4.9 pounds) less than before they started dieting, while those in the low-fat diet group weighed an average of 4.3 kilos (9.5 pounds) less than they did at the start of the study.

Researchers say that while both diets appear to offer weight loss benefits, the pattern of weight change was different between the low-carb and low-fat diet groups.
"The differences in weight regain between the two groups probably reflects initial weight loss," write the researchers. "Participants who lost more weight during the first 12 months tended to regain more weight by month 36."