One to two pounds per week is a healthy amount of weight to lose and is easily sustainable over the long term. If your goal is to lose 15 pounds, you must burn off more calories than you take in. This implies reducing the amount of protein, carbohydrates and fats you are currently consuming daily.
It is recommended that protein make up about 15 percent, carbohydrates about 55 percent, and fat about 30 percent of your daily food intake. If you are currently consuming 2,000 calories per day, this means that 300 calories from protein, 1,100 calories from carbohydrates and 600 calories from fat. When trying to lose weight, the ratio of macronutrients should remain the same, but your overall caloric intake should be reduced.
Your body first uses carbohydrates stored in the liver and muscles for energy. Once you have exhausted these stores, your body will burn fat as its fuel source. It seems only logical to fast when you want to lose weight, but unfortunately, fasting is extremely risky, preventing your body from obtaining essential nutrients. Since a pound of fat consists of 3,500 calories, to lose 15 lbs. of weight an two months, you need to create a caloric difference between consumption and expenditure of a little less than 1,000 calories per day. This can be accomplished through a combination of increased exercise and eating less.
To lose 15 pounds of fat in two months, you must have a caloric differential of 7,000 calories per week. If we assume that half the calories can be lost through increased exercise, 3,500 calories must be lost through eating less. This means a reduction of 500 calories per day. The resulting reduction is 75 from protein, 275 from carbohydrates and 150 from fat.
If 500 calories per day is what you want to reduce to lose 15 lbs. in two months, this translates to 275 calories from carbohydrates or 69 g -- 1 g of carbohydrates is equal to four calories. This means in one week, you must reduce your carbohydrate intake 481 g, or about 3,850 for two months.