If you have a sweet tooth you might be fearful of piling on the kilos in moments of weakness. Picture: File

If you have a sweet tooth you might be fearful of piling on the kilos in moments of weakness.

But millions of people carrying a special variation of a specific gene – which makes them more likely to enjoy sugary treats – may actually have less body fat than average. 

The ‘A' version of the FGF21 gene gives about one in five of us a sweet tooth. And now a study of around 450,000 Britons has found those with two copies of the genetic variant are slimmer than might be expected. 

Those affected had 0.2 % less body fat than others, according to the study led by the University of Exeter.

Scientists think the unexpected results may be explained by people who eat more sugary snacks spending less time eating protein and fat. While nutritionists warn against eating too much sugar, experts believe it is protein and fat that make us more likely to put on weight.

The research, published in journal Cell Reports, analysed more than 450,000 participants from the UK Biobank, which contains medical data on 500,000 people in Britain.