The analysis, conducted by Vasanti Malik, Walter Willett, and Frank Hu from the Harvard School of Public Health, and An Pan from the National University of Singapore, pooled data from 32 cohort studies and randomized controlled trials, and found that sugar-sweetened beverages were associated with weight gain and increases in BMI in adults and children, respectively.
Using data from gold-standard randomized clinical trials only, the Harvard researchers found that children experienced a decrease in BMI gain when sugar-sweetened beverages were reduced, while RCTs in adults showed an increase in body weight when the beverages were added.
‘First line of defense against weight gain is to reduce or stop drinking sugary drinks’
Commenting independently on the study, Professor Marion Nestle from the Department of Nutrition, Food Studies, and Public Health at New York University, told FoodNavigator-USA: “We’ve known for a long time that kids who habitually drink sodas have worse diets and gain more weight than kids who do not.
“But it’s been difficult to say whether this is because the sodas add calories that don’t get compensated for by eating less of other things or because sodas are simply markers of diets generally excessive in calories. Sodas are particularly suspect because they contain sugars and nothing else of nutritional value and the sugars are in liquid form which means they enter the body quickly.
“This study provides even more evidence that the first line of defense against weight gain is to reduce or stop drinking sugary drinks, especially since they come in such large amounts and contain such extraordinary amounts of sugars.”
However, a spokesperson for the American Beverage Association cautioned against singling out one type of food or beverage as the cause of obesity.
“Obesity is a complex public health issue," said the spokesperson.
"Data shows that sugar-sweetened beverages account for only 6% of the calories in the average American’s diet – 94% of our calories come from other sources. That said, all calories count, no matter where you get them. The body of science tells us that what matters most in maintaining a healthy weight is all about balancing calories in and calories out – not singling out one food or beverage.”
Meta-analysis details
Malik and her co-workers analyzed 20 studies with children and 12 studies in adults. After crunching the numbers, the results showed that, in the cohort studies, for every additional 12-oz sugar-sweetened beverage over a one year period body mass index (BMI) increased by 0.06 units.
For adults, every additional 12-oz sugar-sweetened beverage over a one year period was associated with an additional weight gain of 0.12 to 0.22 kg (or about 0.25 to 0.50 lb).
Malik and her co-workers noted that the high added-sugar content (35.0 to 37.5 g of sugar per 12-oz serving), low satiety, and an incomplete compensatory reduction in energy intake at subsequent meals may explain why sugar-sweetened beverages may produce weight gain.
“In addition, fructose from any sugar or HFCS [high-fructose corn syrup] has been shown to promote development of visceral adiposity and ectopic fat deposition,” they added.
“Numerous societies and organizations including the American Heart Association, the American Academy of Pediatrics, and the US 2010 Dietary Guidelines technical review committee have called for reductions in intake of sugar-sweetened beverages to help prevent obesity and improve overall health. Our meta-analyses offer additional support for these recommendations.
“Our results also suggest the need for targeted strategies to reduce sugar-sweetened beverage consumption among high-risk populations, particularly children who are already overweight to prevent further weight gain, and highlight the importance of sustained strategies.”
Source: American Journal of Clinical Nutrition
Published online ahead of print, doi: 10.3945/ajcn.113.058362
“Sugar-sweetened beverages and weight gain in children and adults: a systematic review and meta-analysis”
Authors: V.S. Malik, A. Pan, W.C. Willett, F.B. Hu