The Secret To Staying Slim? Having Skinny Genes

It's not just a question of thin people having greater self-discipline.

Are you feeling demoralised that you’ve stuck rigidly to your new year’s resolutions and still haven’t seen any changes in your body? Take comfort in the fact that your weight isn’t only determined by how much you’re eating.

A new study has confirmed what we’ve long expected – some people are ‘naturally’ more inclined to stay slim as a result of a genetic advantage, not because they’re more disciplined at saying “no” to that extra biscuit.

Not only do they have greater genetic odds of keeping off the weight, but heavier people also have genes that increase their chances of being overweight.

“It’s easy to rush to judgement and criticise people for their weight, but the science shows that things are far more complex,” said Professor Sadaf Farooqi, who worked on the study.

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Cambridge University researchers studied 2,000 people who had a BMI of less than 18, but with no medical conditions or eating disorders. Three out of four people (74%) in this cohort had a family history of being thin and healthy. The researchers found that these people had a “lower burden of genes” that increase a person’s chances of being overweight.

Professor Farooqi’s team collaborated with Dr Inês Barroso’s team at the Wellcome Sanger Institute to compare the DNA with 1,985 severely obese people and a further 10,433 normal weight controls.

The team found several common genetic variants already identified as playing a role in obesity and, in addition, they found new genetic regions involved in severe obesity and some involved in healthy thinness.

“Some people are just not that interested in food whereas others can eat what they like, but never put on weight."”

“This research shows for the first time that healthy thin people are generally thin partly because [of their genes], and not because they are morally superior, as some people like to suggest,” said Professor Farooqi. “Some people are just not that interested in food whereas others can eat what they like, but never put on weight.”

Researchers did acknowledge that eating more high calorie foods and never doing any exercise would impact a person’s weight – but said there’s considerable variation within a population that shares the same environment. In short, we have far less control over our weight than we like to tell ourselves.

The team said if they can find the genes that prevent people from putting on weight, they may be able to target them in new weight loss strategies and help those who are not born with this advantage.