If you have a predilection for fatty fare, you may be able to control it better over the long term by going on a temporary low-fat diet, according to an Australian study in the American Journal of Clinical Nutrition. It looked at the effects of genetics and low- and high-fat diets in 44 pairs of adult twins, both identical and non-identical (fraternal).
People vary in their fat sensitivity, the threshold at which they can detect the effects of fat on the taste and texture of food and on satiety—and it’s thought that people with lower sensitivity may tend to consume foods higher in fat (in order to satisfy their taste buds) and greater quantities of food (in order to feel full). Moreover, it has been shown that the more fat habitually consumed, the higher one’s threshold for fat becomes, meaning that more and more fat is needed over time to result in the same level of satisfaction. Genes have also been thought to play a role in fat sensitivity.
The new study offers hope that the cycle can be broken. It randomly assigned one sibling in each of the pairs of twins to a high-fat diet (with fat providing more than 35 percent of calories) or a low-fat diet (less than 20 percent of calories from fat) for eight weeks, while maintaining a stable weight. Before beginning the diets, the twins underwent lab testing in which both their sensitivity to the presence of fat and their desire for fat were assessed. The testing was repeated at the midpoint and after completion of the diet phase to see if their fat sensitivity and desire had changed.
As expected, fat sensitivity significantly increased in the low-fat diet group at both four and eight weeks, thought to be due to increased expression of certain types of taste receptors on the tongue. In contrast, fat sensitivity decreased in the high-fat diet group. And a reduced intake of fatty foods didn’t lessen subjects’ liking for them.
Somewhat surprising, however, was that it did not make a big difference whether the twins were identical or fraternal, which led the authors to conclude that while genetics may play a role in establishing baseline fat-perception threshold, “dietary intake modifies it.” In other words, you may have been born with a “fat tooth” predisposition, but changing your diet can lessen it.
Bottom line: It’s possible, of course, to have a healthy, high-fat diet if you regularly choose healthy sources of fat, such as avocados, fatty fish, and nuts. But most Americans lean toward fatty fare such as burgers, bacon, butter, ice cream, cakes, and cookies, which is not only an unhealthy eating pattern but also has implications for weight control and susceptibility to obesity.
If you fit into the latter category, a few weeks of low-fat eating may be a relatively easy way to improve your diet without feeling fat-deprived. If it works, it’s a win on two fronts: You’ll be as satisfied consuming lower-fat foods as you previously were with high-fat ones, and you’ll be satisfied after consuming smaller amounts of food overall, thus lessening the chance of overeating.
This article first appeared in the UC Berkeley Wellness Letter.
Also see 14 Keys to a Healthy Diet.