All students aged seven to 18 returning to school from their summer holidays will have to attend daily PE classes, the China Daily reported, citing the Chinese capital's education bureau.
Previously they were required to have PE only once a week, and sometimes even that class was skipped because schools wanted to give students more time to study, it said.
Research from the Beijing Centre for Disease Control showed at least 14 percent of young people had obesity problems, the paper said.
Chinese waistlines have grown in tandem with the nation's economy in recent years, triggering warnings that China could face a public health crisis if nothing is done.
Not only are increasingly wealthy people eating bigger portions, their diet is consisting of more processed and fat-saturated fast foods.
A study published in the US academic journal Health Affairs this year showed that more than 25 percent of adult Chinese are now overweight or obese.