The genes that drive soft drink consumption and weight gain

In a letter to the Editor of the New England Journal of Medicine (NEJM), published online today, endocrinologists from Sydney’s Garvan Institute of Medical Research applauded a study in the 11 October issue showing a direct correlation between consumption of sugary soft drinks, obesity and genetic predisposition to weight gain.

Associate Professor Jerry Greenfield, Professor Katherine Samaras and Professor Lesley Campbell wrote to underline the degree to which appetite is genetically determined (including the urge to drink soft drinks) rather than being solely a lifestyle choice. They also appealed to policy makers to understand the science behind obesity and protect those ‘at risk’.

“Our point is that people are consuming more calories because their genes are driving them to do so,” said Associate Professor Greenfield.

“Genes not only drive people to eat more, they also predispose at-risk people to gain more weight with calorie overconsumption. It’s a double whammy.”

Over the past few years, genome-wide association studies have linked a number of genes with body-mass index (BMI), although few studies have examined the interaction between environment and genetic predisposition to obesity.

The authors of the paper under discussion assessed three large cohorts of men and women in the United States, showing that those with more obesity genes tended to drink more soft drink and have a greater BMI.

The Garvan researchers strongly believe that if policy makers better understand that the drive to eat is not a factor that people can easily overcome, then that appreciation might help inform public health policy.

According to Greenfield, “Policy should reflect the scientific basis of food intake - in other words, people who eat too much and put on weight are not just overconsuming because they are greedy, they actually have a very strong drive to eat.

“Understanding the genes that promote obesity may or may not allow us to develop therapies. At the very least it tells us where, and at whom, to target interventions.”