Most people who have tried substituting margarine for butter or low-fat salad dressing for its full-fat counterpart can tell you that the mouth feel and the taste are different. But some people may be able to perceive that difference more than others, and a study published by the Institute for Food Technologists may have some insight as to why.
Researchers are investigating the gene CD36 and its role in people's ability to taste fat. In a study of 300 African-American adults (one ethnic group was chosen to limit genetic variation) conducted by the New York Obesity Research Center, 21% were found to have a genetic variation. That 21% showed higher preferences for fats and oils and ranked Italian dressing creamier than study participants with other genotypes.
Another gene that may play a role is TAS2R38, a bitter flavor receptor that The Guardian dubbed the Brussels sprouts gene. About 30 percent of people in the U.S. are "nontasters," or don't have those receptors. Nontasters have fewer taste buds than tasters, so they may not detect the presence of fat, and they may eat more to compensate.
All of this might mean that in the future, flavor companies may be able to genotype taste-testers, to get a better understanding of why individuals may react to a certain flavor in a certain way.