Tax relief should be offered on sports activities to help combat growing rates of obesity, doctors have said.
Doctors say sport activities need to be made affordable to everyone
The Royal College of GPs said exercise needed to be made affordable and accessible to everyone in the UK.
The call comes as the government prepares to unveil its public health White paper on how it intends to halt rising obesity in adults and children.
The Department of Health said the NHS already allowed GPs to refer patients to gyms for a subsidised membership.
The Royal College of GPs (RCGP) will discuss the costs of obesity and what doctors can do to treat it at a conference at London's Royal Society of Medicine on Thursday.
More than a fifth of people in Britain are obese and the number of obese children has tripled over the past 20 years.
Dr Graham Archard, chairman of the RCGP Clinical Network, said the issue was of growing concern to the medical community.
"We need to create an environment where everyone is able to balance their busy lifestyles with healthy eating and exercise," he said.
"Most people can't afford sports such as tennis at the moment, not when they cost as much as £5 a game.
"One idea might be to offer tax relief on exercise - after all, obese people are more likely to use more NHS resources than fit and healthy people."
The RCGP is also keen to see healthier foods available in schools to help tackle weight problems among young children.
New research published by the Royal Bank of Scotland and Natwest found that nearly 50% of children spent more than three hours a day watching television or playing computer games.
More than a third never played outside, the survey found.
Last month Culture Secretary Tessa Jowell said she wanted to see more competitive school sport to encourage children to take exercise and discover sporting talent.