GPs could be paid to refer obese patients to slimming classes under guidance from the NHS.
New draft proposals from executive non-departmental public body the National Institute of Health and Care Excellence say doctors should be incentivised to send Britons to schemes such as Weight Watchers.
Ministers are now considering ways to tackle the issue, such as banning price promotions like "buy one, get one free" offers and junk food advertisements during family viewing.
They are also examining ways to boost uptake of slimming classes. The new proposals say GPs should refer all obese adults to "weight management programmes" within three months of them being measured.
With 29 per cent of adults in England now classed as obese – meaning a body mass index over 30 – it could see 12 million people offered help to shed excess weight.
Tam Fry, from the National Obesity Forum, said the move was "a step in the right direction", although he urged GPs to talk to patients about losing weight before they became obese.
In total, 36 per cent of UK adults are overweight, in addition to the 29 per cent who are obese.
"The sooner GPs intervene the better," said Mr Fry. "Ideally, we need GPs to be sending people on for help before they become obese, when their chances of success are higher."
However, GPs claim the idea is unworkable, with too few classes currently available.
Kent GP Dr Stephanie de Giorgio told Pulse, a monthly news-based magazine for GPs: "There aren't the services to send them to, so that's not possible without massive investment when you think of the number of patients this is going to involve.
"Unless significant input is put into effective weight management – which includes psychology, proper nutritional information, obesity medicine and bariatric surgery – then there is really very little point in doing any of this."
Sir Simon Stevens, the chief executive of the NHS, has also called for the UK to do more to tackle obesity following research indicating that those who are obese are twice as likely to die from coronavirus.
The UK – the second fattest nation in Europe after Malta – has so far recorded the third highest number of deaths during the pandemic.
Sir Simon said: "Obesity doubles your chance of dying from coronavirus, and unfortunately we are all carrying too many pounds as a country. So there's a strong case for using the experience of coronavirus to get serious about prevention, including obesity."
Dr Mike Smith, a GP in St Albans, said the "vast majority" of patients who are offered a referral to weight management services declined it, adding: "If everyone did consent to it, the concern would be that an already overwhelmed service would be flooded."