By Nicholas Bakalar, The New York Times, December 12, 2014: It is widely known that being overweight or obese is linked to an increased risk for cardiovascular and other diseases. Now a new study has found that even in young adults of normal weight, increases in body mass index also lead to increased risk. Researchers studied 12,664 young adults, testing them for 32 gene variants known to be associated with higher BMI, and assigning a “gene score” to each depending on how many of the genetic variants they carried. By studying such a large population, they were able to separate genetic tendencies toward weight gain from other variables that may contribute to being overweight, such as diet, physical activity levels and socioeconomic status. Elevated BMI and numerous blood indications of metabolic risk closely matched higher gene scores, strongly suggesting that higher BMI alone causes the increase in cardiovascular risk factors independent of fatty food consumption, exercise, smoking and other variables. The study, online in PLOS Medicine, also analyzed 1,488 people who had metabolic profiles done after six years and found that increases in BMI, even within the normal range, led to extensive adverse metabolic changes, while modest weight loss led to multiple favorable changes. “Our study in young adults shows that even a modest weight loss tends to improve the metabolic profile,” said the lead author, Peter Würtz, head of molecular epidemiology at the University of Oulu in Finland. “It doesn’t have to be a large change to have a beneficial role. Even with a normal BMI of 24, it’s worth it to try to get it lower.”