How Strong is the Science Behind the Soda Ban?

by Kirsten Hartil

SodaOn September 13th 2012, New York City Board of Health voted 8-0-1 in favor (with 1 abstention) to the Administration’s proposal to ban the sale of sodas and other sugar-sweetened beverages (SSB), including sports drinks and energy drinks, greater than 16 oz. The Board of Health’s Notice of Adoption was released shortly afterwards. The new regulation which will become effective March 12, 2013, does not include beverages less than 25 calories per 8 oz., more than 50% milk or 100% fruit or vegetable juice or alcoholic beverages. It will apply only to businesses that are regulated by the city such as restaurants, mobile food carts, delis and concessions at movie theaters, stadiums and arenas but not to grocery or convenience stores. So, despite headlines to the contrary, 64 oz. Big Gulp (100 calories per 8 oz.), 20 oz. caffè lattes and free refills will still be available.

The rationale behind the ban is an effort to halt the increasing rates of obesity and the direct and indirect health care costs associated with it. Obesity is a risk factor for a variety of diseases including Type 2 Diabetes Mellitus, heart disease, stroke and certain types of cancer including colon, breast, esophagus, uterus, ovary, kidney and pancreas. The Harvard School of Public Health estimated that in 2005 the direct and indirect costs associated with obesity in the United States were $190 billion. The NYC obesity task force plan to prevent and control obesity reported that in NYC obesity contributes to 6,000 deaths annually and costs the city $4 billion a year in direct medical costs. 58 percent of adults in NYC (3,437,000 people) are overweight or obese. The Bronx has the greatest prevalence of overweight/obesity in NYC and 1 in 3 public school children in the South Bronx are either obese or overweight.

Consumption of SSB and rates of obesity have been increasing over the last two decades. Serving sizes have also increased, in 1955 the only available size for a soft drink in McDonalds was 7 oz., today the smallest size is 12 oz. (the recommended serving size for a soft drink is 8 oz.). Positive associations between SSB consumption, weight gain and Type 2 Diabetes Mellitus have been demonstrated in numerous peer-reviewed epidemiological studies. Intervention studies have shown that reducing soda consumption decreases body weight in adolescents. A randomized trial published in the New England Journal of Medicine (NEJM) demonstrated that replacement of SSB with unsweetened or diet beverages for 1 yr was associated with a lower body mass index (BMI). Follow-up for 1 yr found no difference in BMI compared with the control cohort. Lack of difference at 2 yrs may be explained by reduced SSB consumption in the control cohort (the authors suggest this may be a result of school interventions to reduce SSB). In addition, the study identified a stronger association between decreased SSB consumption and lower BMI and body weight in Hispanics than in non-Hispanics. A role for genetic predisposition to weight gain with consumption of SSB was demonstrated in a second article published in the same NEJM edition.

Although these studies provide compelling evidence in favor of policies supporting reduced intake of SSB, association does not imply causation. A meta-analysis of 88 studies including cohort, cross-sectional and experimental studies demonstrated positive associations between increased soda consumption, obesity AND caloric intake confounding interpretation of the exact role the SSB contribute to obesity. The NEJM study also reported decreased total energy intake, in addition to decreased sugar intake, in the non-SSB group compared to the control group. One popular hypothesis is that the calories from SSB do not induce satiety the way intake of calories from other sources do. The result is a failure to reduce food intake, ultimately leading to the excess calories being stored as fat. The precise mechanisms why SSB fail to suppress food intake are unknown. Most SSB are sweetened with high fructose corn syrup (HFCS) a mixture of the monosaccharides fructose and glucose. Other SSB are sweetened with pure cane sugar, the main sugar sucrose is a disaccharide of fructose and glucose. Due to differences in how glucose and fructose are metabolized, overconsumption of fructose specifically has been suggested to be responsible for rising rates of obesity and Type 2 Diabetes Mellitus. Fructose (but not glucose) sweetened beverages alter secretion of incretins and appetite stimulating (orexigenic) and suppressing (anorexigenic) hormones in a way that fails to suppress food intake and promote fat storage.

There are myriad issues driving increasing rates of obesity and a literature search will identify articles which refute the role of SSB in this epidemic, for example this article cited by NYC Beverage Choices and this one commissioned by the Union of European Beverages Associations. However, although the molecular and biochemical mechanisms are unclear, the overwhelming consensus is that consuming high amounts of SSB are associated with increased caloric intake and obesity. Only time will tell whether the Soda Bans attempts to reduce excessive consumption of SSB will have the desired effect of reducing obesity and more importantly the poor outcomes associated with an unhealthy lifestyle.

Whether you see the Soda Ban as an assault on freedom or a brave stand in the battle against obesity, NYC is being pro-active when it comes to the health of its residents. The Soda Ban is one of several actions being taken by NYC to improve health and nutrition. NYC Green Carts and the Healthy Bodegas Initiative both aim to increase access to good quality fresh produce in low income neighborhoods. Posting of calorie counts are now required in chain restaurants holding NYC Department of Health and Mental Hygiene permits. In 2006, the NYC approved a ban on the use of artificial trans fats in restaurants and other food service establishments because of its association with cardiovascular disease. These nutritional efforts are accompanied by several initiatives to improve access to physical activity: Shape Up NYC offers free fitness programs throughout the five boroughs; increased bike lanes and the Citi Bike Program, a bike share program which should be launched in 2013, are just three of many initiatives that NYC is supporting.

Some of NYCs efforts within the school system may be yielding results. Following the implementation of School Wellness Programs aimed to increase physical activity, such as Move-to-Improve, and improving the nutritional quality of school meals and vending machines, NYC has seen a small but significant drop in rates of childhood obesity from 2006-2011. These trends suggest that NYC may be moving in the right direction.

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2 Responses to How Strong is the Science Behind the Soda Ban?

  1. Pingback: The U.S. Health Disadvantage – Part 2: Possible Causes and Solutions |

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