Our taste buds are to blame for out fast-food cravings, say researchers in the US who have discovered the gene that makes some of us more inclined to eat fatty foods.
Scientists at the Washington University School of Medicine in St. Louis found that the presence of the CD 36 gene made people eight times more sensitive to the presence of fat.
"In this study, we've found one potential reason for individual variability in how people sense fat," says senior investigator Dr Nada A. Abumrad.
"The ultimate goal is to understand how our perception of fat in food might influence what foods we eat and the quantities of fat that we consume."
A study published in the Journal of Lipid Research involved 21 people who are considered obese, possessing a body mass index (BMI) of 30 or more, and with varying genetics affecting the production rate of the CD36 protein.
Three different solutions were set out. The first contained a low concentration of fatty oil, while the other two contained similar-tasting, non-fat solutions.
Participants were asked to taste all three in a red-lit area, while wearing nose clips to block other sensory indicators such as sight and smell. They then had to choose the cup they thought tasted different.
"We did the same three-cup test several times with each subject to learn the thresholds at which individuals could identify fat in the solution," says first author Dr M. Yanina Pepino.
From previous studies on animals, researchers had ascertained that the CD36 is activated by fatty acids but not triglycerides; a common fat accounting for about 95 percent of all dietary fats.
"In our experiments, people could detect fat whether it was a triglyceride or a fatty acid," says Dr Pepino. She believes this is due to salivary enzymes (lipase) that breaks down the triglycerides to release fatty acids while still in the mouth.
"Diet can affect sensitivity to fat, and in animals," she adds. "Diet also influences the amount of CD36 that's made. If we follow the results in animals, a high-fat diet would lead to less production of CD36, and that, in turn, could make a person less sensitive to fat.
"From our results in this study, we would hypothesize that people with obesity may make less of the CD36 protein. So it would seem logical that the amounts of the protein we make can be modified, both by a person's genetics and by the diet they eat."
It is believed that up to 20 percent of the population possess the variant of the CD36 gene which makes them produce significantly less of the CD36 protein, and in turn less sensitive to fatty foods.
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