Portions of chips will be expected to shrink by up to a quarter under new calorie limits introduced by Public Health England.
The food industry has been asked to cut overall calorie content for most food categories by a fifth, by bringing down the size of foods sold, or their formulation, to remove fat and sugar.
And they have been told that the maximum calorie content of specific products “should not exceed the 75th percentile of the current range of products on the market”.
As a result, a portion of chips should be capped at 270 calories, with a ready meal limited to 570 calories, crisps down to 205 calories, and a sandwich containing a maximum of 580 calories.
Officials said the targets – part of the Government’s obesity strategy – have a “renewed urgency” given the links between excess weight and severity of Covid.
Obesity can double the risk of dying from the virus.
Critics accused health chiefs of a “quixotic crusade to take the flavour out of food”.
But health campaigners said the voluntary measures did not go far enough.
Public Health Minister Jo Churchill said: “We can all do our bit to stay healthy, to help protect us from coronavirus and take pressure off the NHS.
“The food industry can play their part, by making it as easy as possible for everyone to eat more healthily. These guidelines will help them take positive action.”
The 59-page guidance sets out recommended limits for a host of foods sold in restaurants, supermarkets and takeaways
Pizzas should be no more than 1,230 calories, it says, regardless of whether they are bought.
Breaded and battered products such as scampi should be no more than 320 calories, it says.
And a “meal centre” – such as a beef casserole, which might be accompanied with side dishes – should be restricted to 410 calories it says.