The food and drink industry has warned of "devastating" results for consumers and businesses if the UK government moves ahead with plans to restrict how supermarkets sell and advertise chocolate, soda and other foods high in sugar, salt and fat as part of a wider push to tackle obesity.

The new rules will apply to retailers in England with more than 50 employees and are due to kick in by April 2022, the Department of Health and Social Care said in a statement on Monday.

Stores smaller than 2,000 square feet and specialist retailers, such as chocolatiers and sweet shops, will be exempt from some of the restrictions. Offers for unhealthy foods that require shoppers to buy more items to take advantage of the discount such as "buy one get one free" or "3 for 2" promotions will be prohibited in stores and online.

The constraints extend beyond chocolates, soft drinks, sweets and potato chips to pastries, breakfast cereals, pizzas, ready meals and battered products, such as breaded chicken and fish. Unhealthy promotions will no longer be allowed in "key locations," such as checkout counters, store entrances and at the end of aisles.

Free refills of sugary soft drinks in restaurants will also be banned. The new measures will ensure that "the healthy choice is the easy choice," Public Health Minister Jo Churchill said in the statement.

"Creating an environment which helps everyone eat healthier foods more regularly is crucial to improving the health of the nation," she added. But the Food and Drink Federation, which represents manufacturers, said the policy will have "harsh economic impacts" for producers and consumers.

"The proposed restrictions will not only increase the cost of food for families but it will have harsh economic impacts for food and drink manufacturers who are already bracing themselves for the new costs of Brexit and the repercussions of the global pandemic," Chief Operating Officer Tim Rycroft said in a statement.

The restrictions are the latest attempt by the government to tackle Britain's rates of obesity, which are among the highest in the world, according to the Organization for Economic Co-operation and Development.

Britain introduced restrictions on television advertising to children of unhealthy foods in 2007 and implemented a tax on sugary soft drinks in 2018. Earlier this year it launched a new campaign to address obesity, which includes proposals to require restaurants to add calorie labels to menu items.

"Today's announcement forms a key part of the government's strategy to tackle obesity and get the nation fit and healthy," the Department of Health and Social Care said on Monday, adding that the pandemic has highlighted the impact that obesity can have on people's health outcomes.

Studies have shown that being obese or heavily overweight increases the risk of hospitalization and death from Covid-19. Almost two thirds of adults in England are overweight and one in three children leave primary school overweight or obese, according to the government, which said obesity-related illnesses cost the National Health Service £6 billion ($8.1 billion) a year.

"Promotions often appear to help shoppers save money, however data shows that these deals actually increase purchases of promoted products by almost 20% by encouraging people to buy more than they need or intended to buy in the first place," it added.