Boris Johnson will set out his strategy to tackle obesity on Monday – including a 12-week plan for people lose weight and cycling being prescribed by GPs.
It comes after Public Health England research found that being overweight or obese puts people at greater risk of serious illness or death from Covid-19.
Ministers estimate that about two-thirds of adults in the UK are above a healthy weight.
Labour said “radical action” on obesity was long overdue.
It is not yet clear how much new money will be allocated to the anti-obesity drive.
Mr Johnson has admitted that his own weight was a factor in how badly he suffered from coronavirus.
The government estimates that overweight and obesity related conditions are costing the NHS more than £6bn each year.
There were nearly 900,000 obesity related hospital admissions in 2018/19, with obesity a risk factor for chronic diseases including type 2 diabetes, some cancers, liver and respiratory disease.
The “Better Health” campaign will aim to reach 35 million people in a bid “to help them lose weight and live healthier lives”, the government said.
This will be supported by a 12-week plan that people can use to develop healthier eating habits, get more active and lose weight.
A government spokesman said: “Covid-19 has given us all a wake-up call of the immediate and long-term risks of being overweight, and the prime minister is clear we must use this moment to get healthier, more active and eat better.
“We will be urging the public to use this moment to take stock of how they live their lives, and to take simple steps to lose weight, live healthier lives, and reduce pressure on the NHS.”
Under the plans, NHS weight loss services will be expanded so more people get support, and GPs will be encouraged to prescribe cycling in pilot areas identified as having poor health outcomes.
Surgeries will provide access to bikes and ministers are promising local cycling infrastructure will be improved.
This may include segregated cycle lanes, low traffic neighbourhoods and secure cycle parking.
The government is also expected to ban junk food adverts online and before 21:00 on TV, while promotions on snacks will be curbed.
According to the Daily Mail, restaurant and takeaway chains will have to publish the number of calories in the meals they serve – while shops will have to do the same with any alcohol they sell.
Labour’s shadow health secretary Jonathan Ashworth said the UK was facing an “obesity crisis”.
“Radical action on obesity is long overdue. Years of Tory cuts to public health budgets and the backsliding on a pre-watershed ban on junk food advertising have left us with some of the worst rates of childhood obesity anywhere in the world,” he said.
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