TRUE. More and more evidence shows that drinking sugary drinks increases the risk of obesity or weight gain in children and adults, because of the sugar and high-fructose corn syrup in soda, says Julie Salz Greenstein, Deputy Director, Health Promotion Policy, Center for Science in the Public Interest (CSPI) .RUE. More and more evidence shows that drinking sugary drinks increases the risk of obesity or weight gain in children and adults, because of the sugar and high-fructose corn syrup in soda, says Julie Salz Greenstein, Deputy Director, Health Promotion Policy, Center for Science in the Public Interest (CSPI) .