Sugar, Fruit and Weight Gain

A recent study in teenagers found that consuming beverages containing sugar or corn syrup was associated with weight gain.1 A similar conclusion was drawn from data from the Nurses Heart Study, which also found that consumption of sugar-sweetened soft drinks increased the risk of type 2 diabetes even after correcting for weight gain and other known risk factors.2 Does this mean eating fruit might also promote weight gain and type 2 diabetes because its calories also come mainly from sugar?

Fruit Is Much More Than Empty CaloriesSoft drinks provide sugar but no fiber or other needed nutrients. As such, soft drinks provide empty calories, and the more refined sugar one consumes, the greater the dilution of all other nutrients in the overall diet relative to calorie intake. If whole fruit is replaced with soft drinks, intakes of fiber, magnesium and potassium decrease. Reduced intake of these nutrients probably promotes weight gain, diabetes and cardiovascular disease. Fruit juice contains nutrients, but it provides little or no fiber. In that regard it is more like a soft drink than whole fruit.Is Fruit Juice Fattening?The satiety one feels after eating different types of foods depends on many factors. It may well be that sugar-containing soft drinks provide little satiety, whereas eating fiber-rich whole fruits increases satiety and promotes weight loss. However, while no one doubts fruit juice is nutritionally better than a soft drink, it has about the same sugar content and also appears to provide less satiety than whole fruit. The study discussed above also found drinking more fruit juice was also associated with weight gain. The truth is that there are severe limitations to looking at a single dietary factor (i.e., sugar) and trying to determine what role it plays in the development of obesity or other diet-related disease processes. A more useful approach appears to be examining the overall dietary pattern.3Two Studies Suggest Eating Whole Fruit Inhibits Weight GainIn the first study, researchers examined the relationship between changes in body weight and body fat and the intake of foods from different food groups over a 6-year period. Participants who reported eating more fruit were less likely to gain weight and body fat than those eating less fruit. More detailed analysis revealed:• Whole fruit, but not fruit beverages, was associated with a reduced tendency for body fat stores to expand.• Those who reported consuming sugar and sweet foods other than whole fruits appeared to be more likely to gain weight.• Subjects who reported consuming more nonfat dairy products were also less likely to put on more body fat than those who reported consuming fewer nonfat dairy products.• By contrast, those who reported eating more fat and high-fat foods were more likely to gain more weight and body fat.4The second study examined different patterns of eating from 40 different food groups in 459 healthy people. As with the previous study, researchers observed an association with certain food groups and body composition. Again a food pattern of eating more whole fruit and low- and nonfat dairy products and fiber was associated with a reduced tendency to gain weight over time. The authors conclude, “Our results suggest that a pattern rich in reduced-fat dairy products and high-fiber foods may lead to smaller gains in BMI in women and smaller gains in waist circumference in both women and men.”5 The results of these and other studies clearly demonstrate that Americans who wish to stay thinner and be healthier should eat more whole fruits and far fewer refined sugars, especially from soft drinks.Bottom Line:Growing scientific data suggest consuming sugar in a drink promotes increased calorie intake and weight gain, type 2 diabetes and can adversely impact blood lipids. By contrast, while whole fruits contain similar sugars, they appear to protect against weight gain, type 2 diabetes and cardiovascular disease. Fruit juices, while superior to soft drinks in many ways, also appear to promote weight gain, type 2 diabetes and are more likely to adversely impact blood lipids than whole fruit.

 By James Kenney, PhD, RD, LD, FACN.References:1. Obesity Research 2004;12:778-882. JAMA 2004;292:927-343. J Am Diet Assoc 1997;97:272-94. Am J Clin Nutr 2004;80:29-375. Am J Clin Nutr 2004;80:504-13