David Cameron has outlined plans for tough new measures that could see obese people on sickness benefits have their income cut if they refuse treatment for the condition.

Launching a review of the current system, the UK Prime Minister said people who cannot work because they are obese or have alcohol or drug problems would be encouraged to seek medical help under the new proposals.

"Some [people] have drug or alcohol problems, but refuse treatment,” said Cameron as he announced the proposal. “In other cases people have problems with their weight that could be addressed – but instead a life on benefits rather than work becomes the choice.

"It is not fair to ask hardworking taxpayers to fund the benefits of people who refuse to accept the support and treatment that could help them get back to a life of work."

Cameron has asked Department of Health advisor Professor Dame Carol Black to investigate whether withholding benefits from those unwilling to accept help would be an appropriate measure. Opposition parties and obesity campaign groups have said it is “naive” to think overweight people don’t want to change their lives.

The proposals from Cameron follow a recent landmark ruling from the EU court that obesity can in some circumstances be classed as a disability.The physical activity sector has long been pushing to become a frontline service in the battle against obesity, offering an increasing number of weight management services, many of which are linked to referrals from GPs, however progress has been slower than hoped.

An editorial published in the British Journal of Sports Medicine by the ukactive Research Institute, opined that the weak evidence base underpinning the effectiveness of exercise as medicine is holding the physical activity sector back at a time when it should be at the forefront of public health delivery.

Meanwhile, several recent studies have suggested that exercise and a healthy diet may not even be enough to combat obesity in the long-term, with findings indicating that a number of biological adaptations may be to blame for the condition.