A calorie is the amount of energy that food provides. The number of calories is determined by burning food in a device called a calorimeter and measuring the amount of heat produced. One calorie is equal to the amount of energy needed to raise the temperature of one liter of water one degree Celsius. Carbohydrates and protein contain 4 calories per gram, fat contains 9 calories per gram, and alcohol has 7 calories per gram.
All the foods we eat contain calories—some more than others. In order to maintain a healthy weight and to have enough energy to power you through the day, you should try to take in only the amount of calories your body needs—no more, no less (I know—easier said than done!).
How Many Calories Are Right for You?
How do you find the perfect balance between calories in and calories out? Not by nitpicking over calorie counting, that's for sure! You should pay attention to what and how much you eat, but not to the point that you carry a calculator and whip it out after each bite of food.
To get a rough idea of how many calories you should be taking in, look at the following chart. This chart only offers three general caloric ranges, so keep in mind that your personal daily requirements might fall somewhere between two that are listed. Remember, everyone is different. Caloric intake will vary depending upon your age, sex, size, genetics, and level of activity.
|General Daily Calorie Requirements|
|1,600 calories||Number of calories needed for many sedentary women and some older adults.|
|2,200 calories||Number of calories needed for most children, teenage girls, active women, and many sedentary men. Women who are pregnant and breastfeeding may need somewhat more.|
|2,800 calories||Number of calories needed for teenage boys, many active men, and some very active women.|