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Can it! Soda studies cite stronger link to obesity

September 21, 2012|Sharon Begley | Reuters

Once the deliveries stopped the two groups diverged less. After two years, teens who had received the no-cal drink deliveries had gained 9.5 pounds (4.3 kg) and 0.71 unit of BMI, compared to the control group's 11.2 pounds (5.5 kg) and 1.0 unit of BMI.

"It isn't surprising that after the intervention stopped, old behaviors crept back," said Ludwig of the New Balance Center. An "obesogenic" environment that promotes calorie-laden foods "overwhelms individuals' ability to maintain behavioral change" such as avoiding sugary drinks.

Hispanic teens benefited the most: Those receiving no-cal deliveries gained 14 fewer pounds after one year and almost 20 fewer pounds after two. That raised the possibility that genetic factors influence the effect of sugary drinks.

To investigate gene-environment-obesity links, scientists at Harvard School of Public Health looked at 33,097 people from long-term ongoing health studies, such as the Nurses' Health Study, identifying how many sugary drinks they consume and whether they have any of 32 genes linked to obesity.

The effect of genes on the likelihood of becoming obese was twice as large among people who drank one or more sugary drinks per day as among those who had less than one a month, the scientists report in the NEJM. In other words, belting back soda and sugary tea may turbocharge the genetic risk of obesity.

Conversely, eating a healthy diet devoid of sugary drinks keeps fat genes inactive. People with "fat genes" can be thinner if they avoid sugary drinks and other high-calorie foods.

(Editing by Michele Gershberg and Prudence Crowther)