Sugar‐sweetened beverages

With the recognition that the increasing rates of obesity at all ages are a reflection of specific interactions between genetic inheritance and each individual’s environment, the search for environmental factors that have major influences on an individual’s propensity to gain weight and develop the comorbidities associated with obesity, particularly type 2 diabetes, has been a focus of research for many years. This has highlighted, for example, the availability of relatively cheap foods that are high in fat and sugar, and hence highly palatable, as being a significant environmental contributor to the obesity epidemic and the development of type 2 diabetes. However, it is not just the quantity of calories consumed from dietary fat and carbohydrate, but also the composition of these calories that influences weight and metabolic health. Thus, the detrimental influences of saturated fat and trans fats have been recognized along with the beneficial effects of certain polyunsaturates and monounsaturates on body weight and insulin sensitivity. Likewise, the composition and source of the additional carbohydrate calories has been a focus of attention. The most recent data from the US National Health and Nutrition Survey (1) has shown that some 30% of added sugar calories come from beverages, the remaining 70% from food sources, although there is considerable variation among socioeconomic and ethnic groups. The potential impact of the use of high fructose corn syrup in our food has been highlighted (2), and its use to sweeten beverages has brought recent attention to the role that such added sugars in beverages might have in promoting obesity and metabolic disease. With the increasing availability and consumption of these sweetened beverages worldwide, it is appropriate that we should evaluate their possible contribution to the global increase in obesity and such comorbidities as type 2 diabetes. At the annual meeting of The Obesity Society in San Antonio in 2012, Frank Hu (Harvard School of Public Health) and David Allison (University of Alabama at Birmingham) debated the role of sugar-sweetened beverages in the development of obesity and its associated comorbidities. I invited them to publish their views in Obesity Reviews. I am happy that they agreed to take on this task and the resultant manuscripts, updated with new data that have appeared since that debate, are published in this edition as the second of our series of pro vs. con articles started this year. I will leave each reader to evaluate the evidence and come to their own conclusions but would like to thank both Frank, David and their colleagues for presenting their insight in such clear and informative ways. I would be happy to receive any suggestions for future pro vs. con articles.