Studies Examining Whether Sugar Added to Foods Changes Body Weight: Is a Sweet Solution Out There?

This review re-examines the studies relating sugar consumption to development of overweight or obesity as identified for the recent revision of the Australian Dietary Guidelines. All studies identified for the initial evidence review that examined sugars added to foods (one systematic review, three randomised controlled trials, one retrospective cohort study) were re-examined for biases, methodological flaws, and potential confounders that may have affected outcome or quality rating. While the initial evidence review itself followed rigorous methods, methodological issues were evident among primary studies, including short duration of interventions, difficulties with estimating total sugar intake and distinguishing natural versus added sugars, overlooking effects of the food matrix and metabolic differences between glucose and fructose. Few studies examined isocaloric interventions and some introduced concurrent interventions confounding the effect of sugar. Most (71%) of the included studies were funded by the food industry. More high quality, well-controlled longitudinal studies are yet required to support public health messages relating to sugar added to foods and the risk of weight gain.