Lower body fat percentage does not always decrease your chance of having heart disease and diabetes, according to a new study. The study was carried out by an international consortium of investigators, including two scientists from the Institute for Aging Research of Hebrew SeniorLife, an affiliate of Harvard Medical School(HMS).

The researchers found out that a gene that is associated with having less body fat is also linked with an increased risk of diabetes type 2 and cardiovascular disease.

We've uncovered a truly fascinating genetic story and, when we found the effect of this gene, we were very intrigued by the unexpected finding, says Dr. Kiel, a senior scientist at the Institute for Aging Research and a professor of medicine at HMS, according to Reuters.

The study looked into 75,000 people and checked the genes that decide body fat percentage and they discovered a gene called IRS1 was linked with having less body fat. IRS1 also leads people to have unhealthy levels of blood glucose and level of cholesterol, investigators found.

Genetic variants may not only determine the amount of total fat in your body, says Dr. Kiel, but also what kind of fat you have. Some collections of fat, such as the kind located just under the skin, may actually be less harmful than the type located in the abdominal cavity, which may increase the risk of developing metabolic disease.

IRS1 leads to the kind of fat that collects around organs rather than under the skin. According to researchers, people with the IRS1 gene can store less fat just under the skin, leading to storage in parts of the body where organs could be placed at risk.

Men are more sensitive than women to how fat is distributed, which makes them more vulnerable to type 2 diabetes and cardiovascular disease.

The study was published in the journal Nature Genetics on June 26. 2011.