The possible role of sugar-sweetened beverages in obesity etiology: a review of the evidence

Over the second half of the last century, soft drinks and other sugar-sweetened beverages (SSB) have assumed an increasingly significant proportion of total energy intake in the US and most 'westernized' populations. These beverages are heavily marketed to youth and adults. As such, obesity researchers and public health activists and officials have targeted SSB as one of the primary culprits in the escalating rates of obesity. The purpose of this review is to summarize the evidence from human studies on the topic of SSB and body weight regulation, including a brief review of the purported physiological mechanisms, nutritional surveillance and ecological studies, and a more extensive review of the cross-sectional, prospective and experimental studies in humans to date. The equivocal evidence on this topic makes it difficult to draw firm conclusions regarding the role of SSB in the etiology of obesity. Many of the prospective and experimental studies are of unsatisfactory methodological rigor. Some have drawn analogies between the fight against the food industry and the fight against the tobacco industry. However, the complexity of our food supply and of dietary intake behavior, and how diet relates to other behaviors, makes the acquisition of clear and consistent scientific data on the topic of specific dietary factors and obesity risk especially elusive. Only more high-quality randomized trials on this topic will provide the necessary data to more completely evaluate the possible link between changes in SSB intake and obesity risk.