Moderation is usually a good watchword, and new research suggests that this holds true for people worried about fat.
Making new fat from food intake, as opposed to using stored fat, is necessary for health. Scientists haven't understood the molecular mechanisms underlying this benefit, however. To investigate, Clay Semenkovitch of the Washington University School of Medicine in St. Louis and his colleagues deprived mice of both dietary fat and the fat that their own bodies make from sugars. The researchers achieved this by genetically engineering mice to lack an enzyme in their livers called fatty acid synthase, which converts carbohydrates into fat, and then feeding the mice a fat free diet after they reach 4 months old.
The animals' blood sugar concentrations dipped below normal and, ironically, their livers developed fatty deposits. Both conditions were reversed when the researchers restored fat to the animals' diets.