fatty foods

There is a range of sensitivities people have to fatty foods. A study revealed that genetics determines fat taste sensitivity, while diet changes can alter it.

Individuals have different taste sensitivities to fatty foods. This variety in “fat taste” was previously associated with overeating and obesity. People who have low fat-taste sensitivity often eat more fatty foods, have an altered feeling of fullness and tend to prefer fatty foods more than people with high fat-taste sensitivity.

Changes in diet may play an important role in sensitivity to fatty foods

Diet seems to have a critical role in determining an individual’s fat-taste sensitivity. Fat taste sensitivity decreases when dietary fat increases and the fat-taste threshold increases when dietary fat decreases. This suggests that adopting a low-fat diet allows the feeling of fullness to be reached earlier and results in less consumption of fatty food overall.

Fat taste is also associated with obesity, so it is unclear whether weight contributes to fat taste sensitivity. Will adopting a low-fat diet cause weight loss, which will then contribute to an increased sensitivity to fats? Or does adopting a low-fat diet increase fat taste sensitivity independent of weight loss?

Genetics also plays a role in sensitivity to fatty foods

A genetic component has also been implicated in fat-taste sensitivity. Variants in two genes account for an increased perception of fat content in food. Possessing these variants likely increases a person’s fat taste sensitivity, however, it is unclear whether these genetic variants interact with dietary fat to determine fat taste sensitivity.

A research study in Australia, published in The American Journal of Clinical Nutrition, determined the contribution of genetics to fat taste sensitivity and assessed the effects of genetics on diet-mediated fat taste changes.

Researchers performed a paired twin study where one twin in each pair was assigned to eat a low-fat diet (>20% energy from fat), while the other twin was assigned to eat a high-fat diet (>35% energy from fat). Before implementing the dietary changes, participants underwent a series of laboratory tests to determine their starting fat taste sensitivities, as well as their preferences for high-fat and low-fat foods.

Participants maintained their initial body weights throughout the study within 2 kg to control for the effect of weight change on fat taste sensitivity. After adhering to eight weeks of their assigned diets, participants’ fat taste sensitivity was assessed again. Because this study used both identical twins who share 100% of their genes and fraternal twins who share 50% of their genes, researchers were able to assess the effects of genetics on fat taste sensitivity changes after dietary intervention.

Low-fat diets increased sensitivity to fatty foods

As expected, adopting a low-fat diet increased fat taste sensitivity by 64%, and adopting a high-fat diet decreased fat taste sensitivity by 23%. This suggests that people who consume a low-fat diet require less fat to reach a feeling of fullness, and therefore consume less dietary fat overall. Importantly, researchers also found that a change in fat taste sensitivity was independent of weight, as the phenomenon was observed in participants who did not lose or gain weight during the eight weeks. Researchers found that genetic factors influence a person’s baseline fat taste sensitivity but have little effect on how much fat taste sensitivity changes after dietary intervention.

Altogether, this study suggests that people with impaired fat taste sensitivity due to genetics may have lower expression of fat taste receptors on their taste buds and therefore an altered satiety response. However, adopting a low-fat diet can increase fat taste sensitivity in these individuals.

Written by Mallory Wiggans

Reference: Costanzo, A., Nowson, C., Orellana, L., Bolhuis, D., Duesing, K. & Keast, R. (2018). Effect of dietary fat intake and genetics on fat taste sensitivity: a co-twin randomized controlled trial. Am J Clin Nutr, 107, 683-694.

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