At the end 40 years obesity has steadily increased. This happened despite the popularity of all kinds of diets ranging from low carb, paleo or even ice cream.
Many scientists think it’s because cheap junk food has filled supermarket shelves and fast food take away. This food is high in calories and other less healthy ingredients such as saturated fats, simple sugars and salt. But it is designed to this is delicious. Taste is a deciding factor when it comes to deciding what to eat, diet or not. Yet our understanding of what makes food taste good is limited.
My team’s research explored how genes and biological processes influence the foods we find irresistible. We collaborated with British Biobank to ask participants in our study how much they liked 139 foods, rating them from one to nine on a questionnaire, with nine being the most delicious. The UK Biobank is a collection of nearly 500,000 UK volunteers, who have agreed to provide their personal information for scientific purposes. They were between 50 and 70 years old at the time of our study.
We sent out the questionnaire by email and received nearly 189,000 responses. The first step in our study was to analyze the links between the foods people said they liked. For example, if someone likes pears, can they be expected to like apples and strawberries as well? We have mapped the relationships between different foods.
Good taste
We discovered that foods can be classified into three groups: very tasty foods which include meat, junk food and desserts; low-calorie foods, mainly fruit and vegetable salads, but also oatmeal and honey; and acquired-tasting foods which are strong-tasting foods that children generally dislike, but learn to appreciate such as coffee, alcohol and spices.
The map revealed a few surprises. Foods are not grouped by type of flavor (such as sweet or salty), but by their degree of likeability. For example, the taste for fruit juices was more correlated with the preference for desserts than for fruit. Thus, fruit juices went into the highly appetizing rather than low calorie category. Foods that people think of as vegetables don’t group together. Mild flavors like tomatoes or zucchini belong to the low-calorie group while strong flavors, like peppers or onions, belong to the acquired taste group. Sugary drinks like sodas have also moved closer to meat and fried foods despite their sweet flavor.
We then looked at what differences in people’s DNA might be linked to the types of food they enjoy. We have identified 325 different genes, mostly in the brain, involved in determining what we like to eat. When we looked at the extent to which the three food categories were genetically correlated with each other, we found that highly palatable foods had no correlation with the other two food categories. This suggests that there are two biological processes. One regulates a craving for highly enjoyable foods while another regulates the rest.
And after
Twin studies suggest that food preference is 50% genes and 50% personal experience. The family environment plays a role in children’s food preferences but not in those of adults. The change occurs around adolescence. It is still unclear how the taste for different foods matures in children, because no one has conducted large-scale longitudinal studies. My team would like to try to fill this gap in future research.
For our study, we also used brain MRIs to look in more detail at areas of the brain that correlate with the three food groups. We again found that the enjoyment of highly appetizing foods was associated with a greater volume of brain areas involved in the perception of food enjoyment. The other two groups were associated with brain areas involved in sensory perception, identification and decision-making.
These findings shed new light on our understanding of people’s food choices. Understanding why you don’t like certain foods can help you improve the way you cook or prepare them. For example, many people dislike cilantro because it “tastes soapy.” This is genetically determinedgiving some people a sensitivity to a coriander compound. Cooking cilantro instead of eat it raw reduces the soapy taste. This is a simple example, but it shows how a little preparation can make food more palatable.
Healthcare professionals and schools could use information about people’s taste and DNA to identify those most at risk of having unhealthy food choices and help them with early targeted programs. Pharmacological solutions could alter a person’s preference for different types by activating different parts of the brain or hormones. For example, high levels of a hormone called FGF21 can trigger a preference for salty foods, low levels can trigger a preference for sweeter foods. It may be possible in the future to develop drugs that alter the foods you like to eat.
