Effects of weight loss on the fatty acid composition of serum lipids in obese women.

The effect of a weight reduction regimen, consisting of a protein-sparing modified fast and an exercise program, on the fatty acid composition of serum phospholipids and cholesterol esters of obese women, is described. In phospholipids, this treatment did not induce any significant change of the different fatty acid families (total saturated, monounsaturated, omega 9, omega 7, omega 6 and trans-fatty acids), except for total omega 3 fatty acids which increased. Within families, individual fatty acids change however. The changes are compatible with increased delta 5 and delta 6 desaturase activity. In cholesteryl esters, significant changes occurred which are suggestive of an increase in serum of the fraction of cholesteryl esters of intracellular origin. The changes in fatty acid compositions may not be beneficial with respect to atherosclerosis.