If you frequently crave fatty foods, it may not just be a lack of willpower. In fact, it could be genetic.
Research finds people with certain forms of the CD36 gene — which enables animals to both detect and develop preferences for fat — could prefer less-healthy edibles more than those who have other forms of the gene.
In a study with more than 300 African-Americans (an ethnic group chosen because of its propensity for obesity and thus an increased risk of diabetes), a team of scientists from Penn State, Columbia University, Cornell University and Rutgers University gave the volunteers Italian salad dressings made with varying amounts of canola oil, which is rich in long-chain fatty acids.
The participants were then asked to rate their perceptions of the dressings’ oiliness, fat content and creaminess on a scale from “extremely low” to “extremely high.” In addition, they were asked to fill out questionnaires aimed at understanding their food preferences.
The researchers also collected saliva samples from the participants, from which DNA fragments were extracted to determine which forms of the CD36 gene they had.
The results, published in Obesity, showed volunteers who had the “AA” form of the gene — present in 21 percent of the population — rated the salad dressings as creamier than individuals who had other forms of the gene, regardless of how much fat those dressings actually had. The researchers also found that “AA” individuals liked salad dressings, half-and-half, olive oil and other cooking oils more than those who had other forms of the gene.
“It is possible that the CD36 gene is associated with fat intake and therefore obesity through a mechanism of oral fat perception and preference,” said Kathleen Keller, assistant professor of nutritional sciences at Penn State. “In other words, our results suggest that people with certain forms of the CD36 gene may find fat creamier and more enjoyable than others. This may increase their risk for obesity and other health problems.”
She went on to say in a press release that in our evolutionary history, fats were essential for survival, but the gene that makes us enjoy them is less useful to us today.
“Our results may help explain why some people have more difficulty adhering to a low-fat diet than other people and why these same people often do better when they adopt high-fat, low-carbohydrate diets such as the Atkins diet,” said Keller. “We hope these results will one day help people select diets that are easier for them to follow.”
The results could also affect children, with Keller explaining, “By the time we are adults it is very hard for us to change our eating behaviors. So if we can determine which children have forms of the CD36 gene, as well as other genes that are associated with greater liking of fats, we can help them develop healthier eating behaviors at a young age.”