A study published in Obesity Reviews shows that there is not enough evidence to prove that reducing consumption of sugary drinks would reduce obesity rates. The researchers abstracted data from randomized controlled trials and evidence-based reviews through January 2009 concerning effects of consumption of nutritively sweetened beverages (NSBs) on changes in body weight and adiposity. Studies included were those (i) conducted in humans; (ii) lasting at least 3 weeks; (iii) incorporating random assignment of subjects to conditions that differed only in the consumption of NSBs; and (iv) including an adiposity indicator as an outcome. Twelve studies met the inclusion criteria.
Meta-analysis of six studies that added NSBs to persons’ diets showed dose-dependent increases in weight. Contrarily, meta-analysis of studies that attempted to reduce NSB consumption consistently showed no effect on body mass index (BMI) when all subjects were considered. Meta-analysis of studies providing access to results separately for subjects overweight at baseline showed a significant effect of a roughly 0.35 standard deviations lesser BMI change (i.e., more weight loss or less weight gain) relative to controls.
The researchers concluded that “the current evidence does not demonstrate conclusively that NSB consumption has uniquely contributed to obesity or that reducing NSB consumption will reduce BMI levels in general.”