A Less Fattening Fat?

Few people have trouble losing weight—especially over the short run. The problem is keeping the shed pounds from returning. A new study suggests that substituting 5 grams per day of gamma-linolenic acid (GLA), an essential fatty acid, for an equivalent amount of olive oil can limit how many pounds are regained in the first years following a major paring down of weight.

Marie A. Schirmer and Stephen D. Phinney of the University of California, Davis, recruited 50 formerly obese people to take part in a year-long, double-blind trial. That means that neither the researchers nor the participants knew which half of the volunteers were receiving olive oil capsules and which were getting capsules of GLA-rich borage oil. The recruits were also encouraged to log food intake and exercise daily.

Periodically, the researchers weighed each volunteer, calculated his or her body's lean-to-fat ratio, and looked at how the supplemented fat was distributing itself into body fat.

In the May Journal of Nutrition, the nutrition scientists report that men and women randomly assigned to receive the GLA gained, on average, 2.17 kilograms (4.8 lbs), during the first year on the supplements. Those who had instead been taking the olive oil capsules gained more—8.78 kg (more than 19 lbs.).

The researchers then selected 12 subjects in each group to continue on for another year and 9 months. In this case, all openly received the GLA capsules. At the end of this phase, each group had gained back even a little more weight, although now at the same rate. The researchers conclude that GLA, a polyunsaturated fat, may help people limit the speed and overall amount of weight regained by formerly obese individuals.