A calorie is a unit that measures energy. When you hear something contains a certain number of calories, it’s a way of describing how much energy your body gets from eating or drinking it. One calorie is equal to 4.184 joules, a common unit of energy used in the physical sciences. Your body needs calories for energy but eating too many – and not burning enough of them off through exercise – can lead to weight gain. Most foods and drinks contain calories. An example of a low-calorie food is lettuce: one cup of shredded lettuce has less than 10 calories. At the other end of the spectrum are peanuts: a half-cup has 427. The recommended daily calorie intake (if you are of normal weight) is 1940 calories a day for women and 2550 for men.
