Drinking just one 20-ounce soda a day translates to eating 50 pounds of sugar a year, a New York City health department public education campaign says. Dr. Thomas Farley, New York City commissioner of health, said the 30-second TV spot will air on major broadcast and cable TV stations during the next two months as a stark reminder to New Yorkers about how sugary drinks can lead to obesity, which can cause diabetes, heart disease, stroke, arthritis and some cancers. \"The majority of New York City adults are now overweight or obese, as are four in 10 elementary school children, and the health consequences are staggering,\" Farley said in a statement. \"Sugary drinks are the largest single source of added sugar in the diet, and a child\'s risk of obesity increases with every additional daily serving of a sugary drink.\" The TV spot is complemented by bilingual subway posters that ask New Yorkers to think about how far they would need to walk to burn off the calories from drinking just one sugary drink. For example, to burn off the 650 calories of a medium frozen vanilla coffee one would need to walk 8 miles, from the Goethals Bridge to the Verrazano Bridge -- based on a 160-pound person walking 3.5 mph. The campaign encourages New Yorkers to avoid sugary beverages and quench their thirst with water, seltzer or low-fat milk instead.