The makers of Dolmio are warning consumers that some of their sauces have so much salt, fat and sugar they should only be eaten once a week.

Mars Food is introducing new labels to distinguish between "everyday" and "occasional" products.

All Dolmio lasagne meal kits, lasagne sauces, oven bake kits and pesto will fall into the latter category.

It is part of a five-year global health initiative announced by the company.

Mars Food said: "To maintain the authentic nature of the recipe, some Mars Food products are higher in salt, added sugar or fat.

"As these products are not intended to be eaten daily, Mars Food will provide guidance to consumers on-pack and on its website regarding how often these meal offerings should be consumed within a balanced diet.

"The Mars Food website will be updated within the next few months with a list of 'occasional' products - those to be enjoyed once per week - and a list of 'everyday' products."

The ingredients in a 320g jar of Dolmio Bolognese sauce include tomatoes (78%), tomato paste (11%), onions, lemon juice, cornflour, salt, basil (0.3%), sugar, garlic, parsley, herb and spices.

According to the company's website, a 160g serving contains 53 calories, 0.2g fat, no saturates, 6.7g of sugars (7% of the recommended daily intake for an adult) and 1.28g of salt (21% of the RDI).