Several different types of fat have been shown to have important health effects. For example nearly everyone has heard about the many positive effects of fish oil, mainly EPA and DHA. Less publicized is the fatty acid called gamma linolenic acid or GLA for short. Significant sources of GLA include oils made from borage, black currant, and evening primrose. Most research has focused on the anti-inflammatory actions of GLA because it is a precursor to DGLA which is known to produce hormone like substances called eicosanoids that act to reduce inflammation and promote vasodilation. There is also some evidence that GLA supplementation could be involved with body weight control. Researchers from the University of California studied subjects who had recently lost a large amount of weight (average about 60 pounds) to determine if GLA could help prevent regain of body weight. After weight loss, obese subjects were given either 890 mg of GLA (from 5 g of borage oil) or placebo. Over the subsequent year, the placebo group gained over 19 pounds back whereas the GLA group gained only 4 pounds. Because the results were so dramatic, the study was unblinded and the placebo subjects were allowed to start taking GLA and they also experienced benefits of GLA. The study confirmed findings in obese rats that showed GLA suppressed food intake and weight gain. Although the exact mechanisms are unclear, GLA appears to play a major role in r educing weight regain in obese subjects following significant weight loss.

Schirmer MA, Phinney SD. Gamma-linolenate reduces weight regain in formerly obese humans. J. Nutr. 2007 Jun;137(6):1430-5.