A Cabinet minister has urged health officials to leave the public alone, in a backlash against planned calorie limits on restaurant and supermarket meals.

Liz Truss, chief secretary to the Treasury, expressed frustration after The Daily Telegraph revealed proposals to cap the maximum calories in thousands of common foods.

It came as think tanks criticised the plans drawn up by Public Health England (PHE) with the Adam Smith Institute and Institute of Economic Affairs calling for the body to lose its funding.

Under the plans, the food industry has been given until 2024 to cap calories to new limits, with a maximum of 554 calories for a ready meal, 550 calories for a sandwich and a limit of 951 calories for a main course in a restaurant.

Ms Truss was among those expressing horror at the proposals, which come days after the country’s chief medical officer proposed a slew of taxes on sugary and salty foods.

In a tweet on Boxing Day she urged PHE to “leave us alone” joking that she was "too busy eating to engage with this".

Sources said she was "exasperated" at the use of public money to lecture the public, and feared that the latest proposals to cap calories in common foods would result in extra regulation, driving up costs to shoppers.