Supermarkets and takeaways could be fined if they do not sell healthier food, under new government plans to tackle the obesity epidemic.

All large businesses will report their sales of healthy food under the policy, part of a 10-year plan for the NHS unveiled next week.

Targets will then be set to increase the amount sold, with penalties used as a last resort for companies who refuse to work with ministers to reduce the crisis.

Initially developed by innovation agency Nesta, the policy introduces mandatory health targets for retailers while giving them flexibility in how to meet them, such as by tweaking recipes, running price promotions on healthier items, or redesigning store layouts.

Supermarkets will be required to report sales data and those that fail to hit targets could face financial penalties, Nesta suggested.

Cutting out just 50 calories a day could lift 340,000 children and two million adults out of obesity.

Health secretary Wes Streeting said that when it comes to obesity “unless we curb the rising tide of cost and demand, the NHS risks becoming unsustainable”, adding: “Through our new healthy food standard, we will make the healthy choice the easy choice, because prevention is better than cure.”

Anna Taylor, the executive director of the Food Foundation charity, said: “The introduction of mandatory reporting by all large food companies, including takeaway chains, on the healthiness of their food sales is a game-changer. The data will also clearly reveal to consumers which businesses are on their side and making healthy choices easy, and which are making it actively harder for them to eat well. The faster this is introduced, the better.”

Sue Davies, from consumer group Which?, said: “Mandatory food targets will help to incentivise retailers to use the range of tactics available to them to make small but significant changes – making it easier for people to eat a balanced diet and lead healthier lives.”

Ministers argue a healthier nation will put less strain on the NHS, helping to drive down pressure on sky-high waiting lists.

As part of the move, retailers including supermarkets will work to make the average shopping basket slightly healthier.

The Department of Health said that if all those who were overweight cut down on what they ate by 216 calories, the equivalent of one fizzy drink, the UK’s obesity crisis could be halved.

Richard Holden, Tory shadow paymaster general, said: “Making it harder to find crisps is not a substitute for proper reform. Labour ministers are too scared to face up to the fundamental changes our NHS needs.

“In government, the Conservatives made real progress on obesity, stabilising adult rates and cutting child obesity to its lowest since 2000. But we’ve always believed the best results come when people are trusted to take responsibility for their own health.

“Rearranging meal deals will make little difference. This is the worst type of nanny state nonsense there is – shallow, distracting, and completely unserious.”

Britain has the third highest rate of adult obesity in Europe, costing the NHS £11.4bn a year – three times the budget for ambulance services.

An upcoming report by the chief medical officer will show that more than 1 in 5 children are obese by the time they leave primary school, rising to almost 1 in 3 in areas of poverty and deprivation.

Colette Marshall, chief executive at Diabetes UK, said: “The introduction of mandatory reporting and targets on healthy food sales is crucial to improving transparency within the food industry and ensuring businesses can be held to account.

“Public health policies like this, and the junk food marketing ban, have the power to shift the dial from sickness to prevention. The government must build on these commitments in order to stem the alarming rise in type 2 diabetes and its life-altering complications.”