You know it's fattening, but now the hard numbers - 490 calories - may force you to rethink buying that Big Mac in Britain.
About 1,200 McDonald's restaurants in the UK will this week begin displaying the calorie count of each food and drink item on their wall-mounted menu boards, as part of a government-led program to fight obesity and promote healthier eating, the chain said.
McDonald's already puts calorie information on its website and the back of its tray liners, but this is the first time the figures will be displayed prominently in its restaurants outside the US.
The chain has similar calorie menu boards in New York City, which became the first in the US to put a calorie-posting law in place in 2008.
The British program is voluntary, and relies on partnering companies to fulfil their health pledges. Aside from calorie labelling, McDonald's has also promised to remove artificial trans fats from its products, although it did not sign up to a salt reduction pledge.
Other chains that have signed up to the British Department of Health calorie display program include KFC, Pizza Hut and Starbucks.
AP