Researchers from Harvard University report in the August 25 Journal of the American Medical Association (JAMA)1 that young and middle-aged women who increased their consumption of sugar-sweetened soft drinks (soda and fruit punches) over a four-year period gained significantly more weight than women whose consumption of these items remained constant. The same was true of women who increased their fruit juice intake. Such women, not surprisingly, also had a greater risk of developing type 2 diabetes, which is strongly linked to excess body fat and a sedentary lifestyle.
Rather than attributing the increases in weight and diabetes occurrence to the increase in calories from drinking additional sugar-sweetened beverages, the authors seem to blame the sugar in the drinks. Women who increased their sugar-sweetened beverage consumption from less than one per week to more than one per day added over 350 calories to their average daily energy intake. No matter where those calories came from, they would lead to additional weight. An important comparison is lacking here: the authors should have compared the weight gain and cases of diabetes in women who had an equivalent increase in calories from eating foods.
In an accompanying editorial, Dr. C.M. Apovian noted that the women who had higher intakes of sugar-sweetened soft drinks also tended to have other lifestyle factors that could have contributed to their weight gain and increased disease risk. Such women tended to be less physically active, to smoke more, and to have higher total calorie intake and lower intake of protein and fiber. In other words, their overall lifestyle was less healthful than that of women who didn't increase their soft drink consumption.
One possible explanation for the results of this research is that when extra calories are consumed in liquid form, people tend not to compensate for them by eating less food in other meals. Thus they increase their total calorie consumption. Compensation -- either by decreasing calories from other foods or by increasing physical activity -- is necessary to prevent the increases in body weight and risk of disease demonstrated by this study. The take-home lesson? Calories count: those who overconsume them raise their risk of weight gain and concomitant disease.
Ruth Kava, Ph.D., R.D., is Director of Nutrition at the American Council on Science and Health. Around midnight tomorrow (August 26) on the webcast channels http://TV26NewYork.com and http://TV35NewYork.com you can see her discuss nutrition issues in the news.
1Schulze, MB, Manson JAE, Ludwig, DS, et. al. Sugar-sweetened beverages, weight gain, and incidence of type 2 diabetes in young and middle-aged women. JAMA 2004; 292(8):927-934.