According to the Mayo Clinic, 1 pound of fat is equal to about 3,500 calories, meaning that an individual must burn 3,500 more calories than he consumes in order to lose this amount of weight. When losing weight, water and lean tissue mass can be lost in addition to fat.
For effective calorie control, the Mayo Clinic recommends ignoring foods high in calories but low in nutritional value in addition to reducing portion sizes. Replacing high-calorie foods with lower calorie but healthier alternatives is another method. The amount of calories varies in grams by the type of nutrient consumed. Fats contain about 9 calories per gram, while carbohydrates and proteins contain around 4 calories per gram.
The average runner burns roughly 100 calories per mile run; therefore, running 5 miles per day on average every day achieves a weight loss of a pound a week by burning 3,500 calories. Weight loss can also be achieved through a combination of exercise and calorie reduction. If calories are reduced by 200 a day, only 300 additional calories must be burned through exercise per day to lose a pound a week.