Supermarkets will be required to take action to cut the calorie count of your shopping basket in a drive to tackle Britain’s obesity epidemic. Obesity will be halved if overweight Britons cut their daily calorie intake by 216 calories – the equivalent of a single bottle of fizzy drink – a day, experts believe.

It is claimed cutting just 50 calories out of people’s daily diets “could lift 340,000 children and two million adults out of obesity”. The plans to introduce a new “health food standard” have been welcomed by supermarket giants Sainsbury’s and Tesco’s.

Previously, retailers have feared losing sales to their rivals if they promote healthy foods. The new initiative is intended to level the playing field, with shops required to hit targets. The aim is to make the average shopping basket of goods “slightly healthier”.

Retailers will have the freedom to decide how to encourage healthy eating. Measures could include changing the layout of shops, altering recipes, offering discounts and tweaking loyalty schemes.

The UK has the third highest obesity rate in Europe. It costs the NHS £11.4billion a year – triple the budget for ambulance services. Obesity is a key cause of cancer, heart disease and diabetes and there is particular concern about children. A new report from the Chief Medical Officer will show more than one in five children are obese when they finish primary school.

Health Secretary Wes Streeting, said: “Unless we curb the rising tide of cost and demand, the NHS risks becoming unsustainable. The good news is that it only takes a small change to make a big difference.”

He set out an ambition for nurturing the “healthiest generation of children ever”.

“That is within our grasp,” he said, pledging the new initiative will “make the healthy choice the easy choice”.

Environment Secretary Steve Reed said: “Britain has some of the best farmers, growers, food manufacturers and retailers in the world, which means we have more choice than ever before on our shelves. It is vital for the nation that the food industry delivers healthy food, that is available, affordable and appealing.”

Ken Murphy, the chief executive of Tesco Group, backed “mandatory reporting for all supermarkets and major food businesses”, saying: “At Tesco, we have measured and published our own healthier food sales for a number of years now – we believe it is key to more evidence-led policy and better-targeted health interventions.”

Simon Roberts, chief executive of Sainsbury’s, said he wanted to make “good food joyful, accessible and affordable for everyone”.

He said: “We need a level playing field across the entirety of our food sector for these actions to have a real and lasting impact.”

Michelle Mitchell, chief executive of Cancer Research UK, pressed for “further bold preventative policies,” saying: “Being overweight or obese is the second biggest cause of cancer in the UK, and is linked with 13 different types of the disease.”

However, a spokesman for the Adam Smith Institute warned the measures could “drive up prices and restrict choice, making food more expensive for ordinary Brits”.

He said: “Supermarkets already operate on razor-thin margins – the last thing they need is more nanny state interference.”

Richard Holden, Tory Shadow Paymaster General, said: “Making it harder to find crisps is not a substitute for proper reform. Labour ministers 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.”