The firm revealed that the changes would take effect by the end of next year and will include all Mars chocolate products worldwide.
The new calorie-reduction programme is part of the US-based firm’s plan to improve the nutritional value of its products and to promote healthier snacking.
The news comes two years after Mars spent £8.2M on research and development of its products over a period of five years , which included the reformulation of bars such as Milky Way, Mars and Snickers. As a result, the snacks went on sale with 15 to 20% less saturated fat.
Snickers and Twix
The Snickers and Twix maker said that it believed its chocolate products could now feature as part of a healthy and balanced diet.
The changes will affect much-loved chocolate treats such as the Snickers bar, which currently contains 296 calories and the Mars bar, which contains 260 calories.
A spokeswoman told FoodManufacture.co.uk:“We believe that all of our products can be enjoyed as part of a healthy lifestyle and balanced diet - our commitment to making all our chocolate products no more than 250 calories per portion reflects this.
“These changes form part of our on-going efforts to encourage responsible consumption, and will come into effect globally by the end of next year.”
Mars also makes popular brands such as M&Ms and Juicy Fruit chewing gum.