Sugar-free drinks have become popular because of their high calorie content, which can easily lead to obesity. After a period of investigation, Professor Li believes that just because sugar-free drinks are low in calories doesn't mean they won't lead to weight gain. Because sugar-free drinks may lead to a high preference for sweets, this means eating more sugary foods. Moreover, sugar-free drinks have little nutrition, and drinking too much limits the intake of other healthy drinks, such as tea and fruit juices.
Some thin people also like to drink sugar-free drinks can best support Professor Li's point of view if it is true.