Dietary fats, membrane phospholipids and obesity.

Modifications in dietary fat profile have been shown to affect body weight gain and adiposity. This may occur through changes in the partitioning between oxidation and storage and/or alterations in membrane structure, which may in turn influence metabolic rate. All the dietary fat classes are substrates for the biosynthetic elongase and desaturase enzymes. Obesity is associated with increased delta 9 desaturase activity, reduced delta 5 desaturase activity and perhaps reduced delta 6 desaturase activity. Dietary lipid profile can affect the activity of each of these enzymes. A number of possible mechanisms linking dietary fat subtypes with development of obesity are discussed, including modification of sodium potassium pump activity and alterations in mitochondrial proton leakage.