There has been much discussion on the proposal to ban large (>16 oz.) serving sizes of non-diet soft drinks in New York City. I am glad it has people talking about the problem of obesity, but I am not sure this policy is the best approach on balance. My colleagues and I examined the available studies published as of 2010 that might indicate whether such a policy would have the desired effect (Mattes et al., 2010).We found five randomized, controlled studies that had attempted to determine whether asking people to reduce their intake of sugar-sweetened beverages (SSBs, of all types, including soft drinks) would result in weight loss. In people who are already overweight, it appears that there is a very small mean effect in weight reduction, although it is not statistically significant when looking at the range of effects in the whole sample.
This proposed policy might have more power if more people drank larger volumes of SSBs, but it appears that the trend in sweetened beverage consumption has already been going down over the last decade (Welsh et al., 2011). Data from the U.S. National Health and Nutrition Examination Survey (NHANES 2007–2008) indicate that SSB consumption is 6.6% of total energy intake across all age ranges, whereas all added sugars (includes food) is 14.6% of daily caloric intake. Even if we all eliminated all SSBs (based on the reported average daily intake of 2,069 kcal in NHANES 2007–2008) that works out to reducing daily intake by 136.6 kcal. An average 16 oz. SSB has more kcal than that.
Don’t get me wrong, any reduction in intake is a trend in the right direction. However, as a Health Psychologist, I think there are other ways to help people make better choices without limiting personal freedom. There is experimental evidence that when given a range of choices that includes smaller sizes, e.g., 12 oz., more people will choose a beverage size that is smaller than the most extreme size (Sharpe et al., 2008). Another option might be caloric content in the “between” range, e.g., sodas that have half the calories as the full sugar version. This might help people transition from full sugar sodas to diet versions so that they can get used to the lower kcal version gradually.
Obese populations are made up of obese individuals, with varying and complex factors driving body weight. It seems our biology drives weight gain in optimal conditions and resists permanent weight loss. As much psychological research has shown, very often the situation is stronger than the individual. In the present environment, this requires conscious effort for individuals to avoid opportunities to over consume. However, one need not wait on public agreement or policy enactment to make different choices. The challenge is in cutting through the noise to find what works, not for the entire population, but for that one individual.
I tell people to “be your own scientist.” Science is the business of measurement, and in weight management it begins with measuring body composition, physical activity, and food intake. I would like to see policies that make these fundamentals and evidence-based education to support them being made freely available to everyone. We are beginning to see such things in schools and in the workplace, but we have much more to do. The need is urgent.
For a healthier future, scientists, policy-makers, as well as food manufacturers and suppliers must create a culture of cooperation for the common good. For this to be sustained, forces ranging from macroeconomics to individual psychology and biology must be taken into account. To this end, I hope the dialog (and science-based action) continues.
Mattes R.D., Shikany J.M., Kaiser K.A., Allison D.B., 2010. Nutritively sweetened beverage consumption and body weight: A systematic review and meta-analysis of randomized experiments. Obesity Reviews 12: 346-365.
Sharpe, K., Staelin, R., Huber, J., 2008. Using Extremeness Aversion to Fight Obesity: Policy Implications of Context Dependent Demand. J Consum Res 35: 406-422.
Welsh, J., Sharma, A., Grellinger, L., Vos, M., 2011. Consumption of added sugars is decreasing in the United States. Am J Clin Nutr 94: 726-734.