An effect of drinking sports drinks with carbohydrates without prolonged exercise is weight gain. A study presented at the Obesity Society's Obesity 2012 scientific meeting found people in their teens gained over two years for every bottle of sports drink consumed per day. The leading author of the study, Alison Field of Harvard Medical School, said she was surprised to find that "Sports drinks have an even stronger relationship than sugared sodas with weight gain". In August 2019, a study by University College London found that sports drinks were causing high amount of tooth decay in professional athletes because of high sugar content.