First, the obvious: Sugar adds empty calories to your diet, and if you're not careful, that can add inches to your waist. Keep that up, and it could lead to obesity, which brings a host of other health problems such as heart disease, says Laura Schmidt, Ph.D., a professor of health policy in the School of Medicine at the University of California, San Francisco.
But many of the issues brought about by excess sugar consumption are believed to be completely unrelated to obesity and more about how the substance is metabolized in your body. "Studies in animals show that fructose intake in particular can alter your ability to control appetite, reduce your ability to burn fat, and induce features of metabolic syndrome, such as raising blood pressure, increasing fat, and causing fatty liver and insulin resistance," says Richard Johnson, M.D., professor of medicine at the University of Colorado in Denver and author of The Fat Switch.
One other not-so-sweet side effect of sugar: wrinkles. "When your body digests sugar molecules such as fructose or glucose, they bind onto proteins and fats and form new molecules called glycation end products, or AGEs,” says David E. Bank, a dermatologist in Mount Kisco, NY and SHAPE advisory board member. As AGEs collect in your cells, they start to destroy skin’s support system, a.k.a., collagen and elastin. “As a result the skin is wrinkly, inflexible and less radiant,” says Bank
Related: This supplement may be the best way to fight the aging effects of sugar.