London | People who carry a particular gene variant have a higher craving for fat-rich chicken korma but a decreased preference for sugary foods, according to a new Cambridge led study that may help treat obesity.
The research provides insights into why we make particular food choices, with potential implications for our understanding of obesity, researchers said.
This is one of the first studies to show a direct link between food preference and genetic variants in humans.
Previous studies in mice have shown that disruption of a particular pathway in the brain involving the melanocortin-4 receptor (MC4R) can lead to mice eating a lot more fat.
Unusually, these mice eat a lot less sugar.
Researchers at the University of Cambridge in the UK gave participants an all-you-can-eat buffet of chicken korma – a popular type of curry – with three options manipulated to look and taste the same, but in which the fat content provided 20 per cent (low), 40 per cent (medium) and 60 per cent (high) of the calories.
They tested lean people, obese people and people who were obese because they have a defect in a gene called MC4R.
After taking a small taster of each meal, people were allowed to eat freely from the three kormas. They could not tell the difference between the foods and were unaware that the fat content varied.
Researchers found that, although there was no overall difference in the amount of food eaten between the groups, individuals with defective MC4R ate almost double the amount of high fat korma than lean individuals ate and 65 per cent more than obese individuals.
In a second arm of the study, people were given Eton mess, a dessert that includes a mixture of strawberries, whipped cream and broken meringue.
Again, there were three options from which participants could freely choose.
Lean and obese individuals said they liked the high sugar Eton mess more than the other two desserts.
However, individuals with defective MC4R liked the high sugar dessert less than their lean and obese counterparts and in fact, ate significantly less of all three desserts compared to the other two groups.
One in 100 obese people have a defect in MC4R gene which makes them more likely to put on weight, researchers said.
They think that for these individuals, the fact that the MC4R pathway is not working may lead to them preferring high fat food without realising it and therefore contribute to their weight problem.
“Our work shows that even if you tightly control the appearance and taste of food, our brains can detect the nutrient content,” Professor Sadaf Farooqi from the Wellcome Trust–Medical Research Council Institute of Metabolic Science at Cambridge, who led the research team, said.
Farooqi and colleagues think that humans may have evolved pathways in the brain that modulate the preference for high fat food in order to cope with times of famine.
The study was published in the journal Nature Communications.
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