A gene that keeps people slim may heighten their risk of heart diseases and type 2 diabetes, according to researchers.
In a study published in the journal Nature Genetics, the group details the discovery of a gene that cuts down fat accumulated under the skin but not around the internal organs.
Although the gene keeps the individual visibly lean, it was found to result in increased levels of unhealthy cholesterol and glucose in the bloodstream.
According to Professor Jeremy Pearson, associate medical director at the British Heart Foundation, it may help explain why even some slim individuals face increased risk of life-threatening diseases usually associated with being overweight.
He said: "These results reinforce the idea that it is not just how fat you are, but where you lay down fat that's particularly important for heart risk. Fat stored internally is worse for you than fat stored under the skin.
"The results help us to understand why some slim people become insulin resistant, which is the first stage of type 2 diabetes, and may lead to better targeted use of medicines to prevent insulin resistance in future.
"However, they don't detract from the fact that being overweight is bad for your heart health, so we should still try to stay lean and fit."