Drink a 20-ounce soda daily, and you may be causing your cells to age as much as they would if you smoked, a study suggests. Researchers investigated DNA from 5,309 adults, focusing on telomeres, the caps on the ends of our cells' chromosomes, Time reports. They found that drinking sugary soda was associated with shorter telomeres—and it's known that telomere length may be linked to life span, according to a University of California-San Francisco report. Shorter telomeres also appear to be linked to heart disease, cancer, and diabetes. In the study, a daily 20-ounce soda was associated with an extra 4.6 years of aging—the same figure seen in smokers.
About 21% of subjects said they drank that much soda daily, while the average intake was 12 ounces. Researchers also looked at the effects of diet soda and fruit juice on telomeres; while "100% fruit juice was marginally associated with longer telomeres," they write in the American Journal of Public Health, diet sodas and non-carbonated "sugar-sweetened beverages" weren't associated with telomere length. Still, the study points to the dangers of soda beyond its role in obesity. "The extremely high dose of sugar that we can put into our body within seconds by drinking sugared beverages is uniquely toxic to metabolism," says a study author. (If you can't give up soda, here's why you should consider taking 12,000 steps a day.)