THE CAUSES OF OBESITY: GENETICS - GENETIC TASTE VARIATIONS

One interesting area of research is the study of genetic taste variations and their possible implications for obesity. Awareness of differences in the ability to detect taste began in 1931, when Dupont scientist Arthur Fox was synthesizing a chemical called PTC. By accident, some of it blew into the air, creating a terribly bitter taste for another man who inhaled the substance but making no noticeable impression on Fox. Further investigation revealed that some people could not taste this substance while another group could and that there was a third group in the middle. The terms "nontasters," "supertasters," and "medium tasters" were used, respectively, to describe these groups, and it was learned that there was a genetic component that helped explain the variations.

So, how does this relate to weight loss? If supertasters have an unusually intense response to bitterness, they may tend to avoid healthful fruits and vegetables, foods that help keep people slim. Some researchers also theorize that supertasters may have a greater sensitivity to more pleasant-tasting sweets, salt, and fats, which makes them more likely to favor these foods. Others counter this contention, however, asserting that a liking for fat is universal. Dr. Adam Drewnowski, director of the nutritional sciences program at the University of Washington, holds this view, pointing out that "there's a very sensitive censure mechanism that turns you off to sugar, and it kicks in in an adult's life. For example, children like very, very sweet things; adults do not. Adults find sugar candy way too sweet. But this mechanism does not exist for fat. Things are never too rich or too creamy or too fatty; there's no limit. I suspect that this is because we were never really meant to eat fat. Fat was fairly rare in the food supply until 200 years ago when we had vegetable fats being turned out cheap by the industry. And as a result we do not have a natural physiological protection against eating too much of it."

Further research needs to be done on these issues. But even if we don't understand everything about how we accumulate extra weight, we do know how to control the tendency, which is the important thing.

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