The study on twins, conducted by researchers from the University of Deakin, Australia and published in the American Journal of Clinical Nutrition, suggests that an individual’s taste for fatty foods is not driven by genes but by diet.
Lead researcher professor Russell Keast, director of Deakin’s Centre for Advanced Sensory Science said: “There’s this idea that maybe some people are just not as good at sensing high levels of fat, and that they’re born that way.
“But what we found is that genetics does not provide any protection against the dietary influence of fat. If we eat a high-fat diet, we lose our ability to sense fat.”
The researchers conducted an eight-week dietary-based experiment in which 44 pairs of adult twins were, within each twin set, were allocated to either a low- or high-fat diet.
Those in the low-fat diet got less than 20% of their energy from fat while the other group got more than 35% of energy from fat and were encouraged to eat more dairy, meat and oil.
Despite the difference in fat, the energy-intake of each group was identical in terms of kilojoules, and both groups were monitored to ensure their weight stayed within a normal range.
At the start, middle and end of the experiment, the researchers measured each participant’s sensitivity to fat by giving them three cups of liquid and asking them to identify which cup had a fatty acid.
Those who could not tell the difference were given an increased concentration of fatty acid.
At the one- and two-month mark, the low-fat twins were able to identify lower concentrations of fatty acid than their high-fat siblings.
"People who have a lower sensitivity to the fat taste end up eating far more kilojoules from fat because they need more to feel satiated,” said Keast. “That’s why it’s vitally important we’re careful with what we’re eating, otherwise we will get in a bad cycle of our bodies becoming accustomed to high levels of fat and requiring higher levels of fat to become satisfied. That can then lead to obesity.”
“The current study shows that eight weeks of consumption of a low-fat diet increases sensitivity to fat taste and the same period with a high-fat diet attenuates sensitivity, regardless of body weight. There is little indication of genetic contribution on fat taste. Therefore, dietary fat intake is the most important influencer on fat taste sensitivity,” the authors conclude.
“Diets that approach the lower Acceptable Macronutrient Distribution Range (AMDR) for fat may aid in increasing the satiety response to fatty food, decrease passive overconsumption, and subsequently reduce body weight,” they write.
Source: The American Journal of Clinical Nutrition
“Effect of dietary fat intake and genetics on fat taste sensitivity: a co-twin randomized controlled trial”
Published online ahead of print: 11 April 2018, doi.org/10.1093/ajcn/nqy022
Authors: Andrew Costanzo, Caryl Nowson, Liliana Orellana, Dieuwerke Bolhuis, Konsta Duesing, Russell Keast