The consumption of a restricted range of foods leads to diminished food intake in both animals and humans, a phenomenon that is known as sensory-specific satiety. The introduction of a new food into a meal may overcome the satiety response. Obese individuals are more sensitive to food palatability than those individuals who are of normal weight. The obese are more likely to avoid foods of low palatability and more likely to prefer highly palatable foods. The composition of the diet consumed by Americans has changed remarkably over the years.
Studies suggest that short-term fat balance is directly influenced by fat intake.
This storage is regulated by the enzyme lipoprotein lipase. Fat deposits in highly active sites are associated with higher cholesterol levels and other cardiac risk factors. Because men tend to accumulate abdominal fat, which is broken down by the more active form of lipoprotein lipase, they generally lose weight more readily than women, who accumulate hip fat. Experimental work in animals and epidemiological surveys in humans suggest that stress may lead to the deposition of abdominal fat. Cigarette smoking has also been associated with preferential deposition of fat around the abdomen, despite the fact that smokers have a lower level of adiposity than nonsmokers.