It is an interesting, if potentially rude, question that encompasses a broad church of possible topics. Are you about to be criticized for your taste in art? Theatre? Books? Clothes or music perhaps? And of course, let us not forget food.

A large proportion of food tastes are acquired.

Take the different types of starchy carbohydrates, which make up more than 50% of calories consumed throughout the world. My wife, who is of white Northern European ancestry, loves it in the form of bread. I am of Chinese ancestry, and can take or leave bread.

Rice and noodles however, I can easily eat every single day. Thus, the love of carbs is largely universal, but the ‘tastes’ for its different forms are culturally embedded from an early age.

What is less well known is that there are actually genes that influence our ‘taste’ for certain types of food.

Genetic Influences on Feeding Behaviour

In my lab, we study the genetics of body-weight. We now know this to be powerfully influenced by how our brain controls our feeding behaviour. One of the key genes that plays a role in the control of food intake is the melanocortin 4 receptor or MC4R. This gene is part of the circuit in our brain which detects how much fat our bodies are carrying.

Why is this important?

Because a genetic mutation in the MC4R gene has big impacts on our eating habits. People with mutations in MC4R have brains that are less sensitive to the amount of fat in the body. Their brains think they are carrying less fat than they actually are. As a result, they eat more, and end up heavier.

Around 0.3% of the UK population, potentially up to 200,000 people in the country, carry mutations in the MC4R. That makes them, at 18 years of age, on average 18 kg heavier that someone without an MC4R mutation. Of that 18 kg, 15 kg is fat!

But the MC4R gene mutation doesn’t only influence how much we eat. It also impacts what we eat. A colleague of mine here in Cambridge, Professor Sadaf Farooqi, devised two different experiments, to try and understand the role that MC4R plays in influencing food choice.

MC4R genetic mutation

She tested lean individuals, and individuals with obesity with and without MC4R mutations. In the first experiment, she gave participants an all-you-can-eat buffet with three options of chicken korma (a mild, sweet, almond based curry). The three curries were the same, in look, smell and taste but differed in fat content. They were each manipulated to provide a ‘Goldilock’s-selection’ of 20% (low), 40% (medium) and 60% (high) of the calories from fat.

Those carrying a mutation in MC4R ate almost twice the amount of high fat curry than the lean individuals. They also ate 65% more than individuals with non-MC4R obesity.

In the second experiment, the same three groups were given Eton mess. This is, in effect, a smashed-up Pavlova of strawberries, whipped cream and meringue. Again, there were three options from which to choose, this time differing in the amount of sugar present in the meringue and cream, providing 8% (low), 26% (medium) and 54% (high) of calorific content.

Paradoxically, in contrast to the fat choice experiment, individuals with a mutation in MC4R liked the high sugar dessert less than their lean and obese counterparts. In fact, they ate significantly less of all three desserts compared to the other two groups. It turns out that people with a defective MC4R preferred higher fat food, but had a decreased preference for sugary foods.

The Genetics Behind Supertasters

How about the taste or distaste for specific types of food? Brussel sprouts for instance?

I once did a talk at the Royal Institution in London about the genetics of feeding behaviour and performed a demonstration with 12 people from the audience. Everyone got a blank bit of paper, and was told to put it on their tongue (I did it too, to reassure that I wasn’t trying to poison anyone).

Half of the volunteers (including me) encountered an acutely bitter taste. The other half tasted nothing, and were looking around, puzzled by the difference in reaction. What was going on?

Well, all the pieces of paper were infused with a little drop of phenylthiocarbamide. This is the chemical responsible for the bitter taste found in brassica, plants in the cabbage and mustard family, which include Brussel sprouts. However, only around 50% of people, known as ‘supertasters’, carry a variation of the gene TAS2R38. This is the gene that allows them to detect the bitterness. The ability to taste this bitterness doesn’t automatically mean you hate sprouts. It does however influence the taste sensation you get from eating them and other related vegetables.

Preference vs genetic influence

Then there is the marmite reaction of different people to the herb coriander (or cilantro, depending on where in the world you hail from). Many people find it tasty (me), but some, famously, the chef Julia Child, find it disgusting. This dislike may, of course, simply reflect preference. However, for those coriander-phobes amongst you, for whom the herb has a strong soapy taste, it is indeed genetic.

Some people have a genetic variation in the olfactory-receptor gene OR6A2. This allows them to strongly perceive the aldehydes in coriander leaves, which are the source of the soapy-flavour. Interestingly, the prevalence of this genetic variation varies geographically. Regions where coriander is more popular, such as Central America and India, have fewer people carrying this ‘soapy’ variation.

So next time a dinner companion expresses a like or dislike for a specific food, it could be for cultural reasons, but it could indeed also have a genetic basis.

Whatever the reason, it is probably best not to judge!

Professor Giles Yeo MBE is the Programme Leader at the MRC Metabolic Diseases Unit in Cambridge. His research currently focuses on the influence of genes on feeding behaviour and body weight.

Understanding genetic differences is tricky but Giles’s online course with the University of Cambridge Online(Opens in a new window) provides answers. Discover more: https://bit.ly/3IgNV68(Opens in a new window)