Have you ever wondered how fattening your favourite burger is? Maybe not, but the government reckons we should know.
McDonald's has signed up to a government plan to put calorie information on their menus, which can help tell you how healthy the food is.
Other fast-food companies, including KFC and Pizza Hut, have already agreed to do it. Politicians hope it will encourage people to eat more healthy food.
Everything you eat or drink, apart from water, contains calories. They aren't bad for you, and your body needs them for energy.
But if you have too many and don't do enough exercise then you can gain weight and that can lead to health problems.
A child aged between four and 11 needs between 1600 and 2500 calories per day.