A new study from Deakin University reveals it’s not your genes that determine your sensitivity to fat – it’s what you’re stuffing into your pie hole!
An eight-week study involving 44 sets of Australian twin adults has been conducted by Deakin University, and the results suggest that if you want to lose weight, choosing lower-fat foods can provide a double benefit, because not only will you be directly consuming less fat, but doing so is believed to gradually increase your sensitivity to the taste of fat. And while this won’t change how much you enjoy the taste of fatty foods, the small amount of fat that you do eat will make you feel fuller quicker – which means you’re likely to consume less kilojoules overall.
The findings from this NHMRC-funded study were published last week in the American Journal of Clinical Nutrition, and revealed that your taste for fat is not driven by genetics but more your overall diet. It found that those who consumed a lot of fat-laden foods had a reduced sensitivity to the “taste” of fat, regardless of their body weight or genetics.
The study saw one in each pair of twins being randomly allocated to a low-fat or hig-fat diet (getting less than 20% or more than 35% of their energy from fat, respectively). Those on the high-fat diet were encouraged to eat more dairy, meat and oil, but each person actually consumed the same number of overall kilojoules, and they were monitored to keep within their normal weight range.
Each person’s taste for fat was tested at the start, middle and end of the trial. And at each test, each twin was given three small unmarked cups of liquid, and had to identify which of the cups contained a fatty acid. If they were unable to do so, the concentration of fatty acid was increased.
At four and eight weeks, the twins on the low-fat diets were able to identify the fatty acid at a lower concentrations than their twin on a high-fat diet.
“It’s important we’re careful, otherwise we will get in a 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.”
Lead researcher Professor Russell Keast, who is also the 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.”
Professor Keast said this was significant due to the strong link between satiety (i.e., the feeling of fullness) and taste sensitivity. “If you are eating too many high fat foods,” he explained, “fat becomes an invisible nutrient. The satiety response becomes very important because consumers have to be satisfied to stop eating.
“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,” he added. “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.”
Andrew Costanzo, a co-author on the study and a researcher at the Deakin School of Exercise and Nutrition Sciences, said that on average, Australians take in about 31% of their energy from fat, which is within the recommended 20 to 35% range.
“The issue begins with individuals who consume quantities of fat above this range,” he explained. “A moderate amount of fat is good for our health, but excess fat becomes a problem. In the longer term we can build an increased sense of satisfaction for foods with a lower fat content, but we’ve just got to battle those hard initial weeks.”