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
- 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.
Tipping the scale: Cutting calories
Your weight is a balancing act, but the equation is simple: If you eat more calories than you burn, you gain weight.
Because 3,500 calories equals about 1 pound of fat, you need to burn 3,500 calories more than you take in to lose 1 pound. So if you cut 500 calories from your typical diet each day, you’d lose approximately 1 pound a week (500 calories x 7 days = 3,500 calories).
Cutting calories doesn’t have to be difficult. In fact, it might be as simple as forgoing one extra item a day, swapping foods or trimming serving sizes. The number of calories you save is likely to translate into pounds lost.
