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Counting calories: Getting back to weight-loss basics
Your weight is a balancing act and calories play a big role. Find out how calories determine your weight and ways you can best cut calories from your diet.
By Mayo Clinic staffOf all the diet strategies out there, it still comes down to the calorie. Fad diets may promise you that counting carbs or eating a mountain of grapefruit is key to weight loss, but when it comes to weight control, it's calories that count.
Calories: Fuel for your body
Calories are the energy in food. Your body has a constant demand for energy and uses the calories from food to keep you functioning. Energy from calories fuels your every action, much as gasoline powers your car.
Carbohydrates, fats and proteins are the types of nutrients that contain calories and thus are the main energy sources for your body. The amount of energy in each varies: Proteins and carbohydrates have about 4 calories a gram, and fats have about 9 calories a gram. Alcohol also is a source of calories, providing about 7 calories a gram.
Regardless of where they come from, calories you eat are either converted to physical energy or stored within your body as fat. Unless you use these stored calories — either by reducing calorie intake so that your body must draw on reserves for energy, or by increasing physical activity so that you burn more calories — these calories will remain within your body as fat.
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