Researchers reviewed more than 40 years of studies and found the recent increase in consumption of sugary soft drinks and other sugar-sweetened drinks, like fruit drinks, lemonade, and iced tea, is associated with weight gain and obesity.
"Although it has long been suspected that soft drinks contribute at least in part to the obesity epidemic, only in recent years have large epidemiologic studies begun to investigate the relation between soft-drink consumption and long-term weight gain," writes Vasanti S. Malik, of the Harvard School of Public Health, and colleagues in the American Journal of Clinical Nutrition.
Soft-Drink Trends Parallel Obesity Rise
The results show that non-diet soft drinks are the largest source of added sugars in the American diet, and consumption of these drinks increased 135 percent between 1977 and 2001.
During the same time period, obesity ballooned to epidemic proportions in the United States, with nearly two-thirds of adults 20-74 years now overweight or obese.
A single, 12-ounce can of soda contains 150 calories and around 40-50 grams of sugar in the form of high-fructose corn syrup, or the equivalent of 10 teaspoons of table sugar.
Researchers say adding the calories from a single soda a day to the typical U.S. diet could mean a weight gain of 15 pounds over a year.
Educating Americans About Sodas And Weight Gain
For their study, the researchers reviewed 30 studies published between 1966 and 2005.
Long-term studies showed an association between increasing consumption of sugar-sweetened drinks and weight gain as well as obesity among children and adults.
In addition, the researchers reviewed a study in schoolchildren that showed an educational program advocating fewer sugary sodas reduced weight gain and obesity among the kids after 12 months.
Another study looked at adolescents who reported drinking sugary soft drinks every day. Half the teens were provided with zero-calorie diet beverages delivered to their homes for 25 weeks. There was a drop in consumption of sugary drinks by 82 percent in those teens, along with improvement in body weight compared to the teens who continued their usual soft-drink use.
"Given the global incidence rates of overweight and obesity are on the rise, particularly among children and adolescents, it is imperative that current public health strategies include education about beverage intake," write the researchers. "Consumption of sugar-sweetened beverages such as soda and fruit drinks should be discouraged, and efforts to promote the consumption of other beverages such as water, low-fat milk, and small quantities of fruit juice should be made a priority."
SOURCE: Malik, V. American Journal of Clinical Nutrition, August 2006; Vol. 84: pp. 274-288.
By Jennifer Warner
Reviewed by Louise Chang, M.D.
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