According to government-commissioned research half of all Britons will be obese in 25 years if current trends are not halted; furthermore, 86 percent of men will be overweight in 15 years and 70 percent of women in 20, it suggested.
"For the first time, we are clear about the magnitude of the problem: we are facing a potential crisis on the scale of climate change, and it is in everybody's interest to turn things round," said Health Secretary Alan Johnson.
Prime Minister Gordon Brown launched a new 100-million-pound programme Monday aiming to increase from two to five the number of hours of physical education in schools per week.
Some 2.3 million pounds has already been set aside in the last 10 years to increase the number of hours of sport in school.
But Schools Secretary Ed Balls said sports facilities alone would not stop the phenomenon in its tracks.
"There's a role for schools in showing leadership," he said. "But it's what parents and kids do at home and after school which matters most."
In particular, he said that more needed to be done to encourage girls to keep playing sport.