To lose weight, a person must consume fewer calories than he uses each day. A safe amount to lose each week is 1 to 3 pounds, which would be between a half a pound and 1.5 pounds in three days. Creating a caloric deficit of 500 to 1500 calories each day typically results in this amount of weight loss.
Heavier people can lose larger amounts of weight in the same amount of time while staying healthy. Reducing salt intake can result in a larger initial loss due to a loss of water weight. Limiting starch intake also helps lessen fluid retention. Together, limiting these two things can result in up to 5 pounds of lost weight.
To create this deficit, a person must eat fewer calories than his maintenance level while retaining the same amount of physical activity, or eat at maintenance levels while increasing physical activity. For example, a 200-pound person can burn over 500 calories in an hour by bicycling at 12 miles per hour.
Alternatively, mix and match by consuming fewer calories and exercising more to get the benefits of both styles of weight loss. Increased water and vegetable intake help a person feel full, which makes it easier to create a calorie deficit without feeling hungry. Meals should be spread out over the day and eaten more frequently. The idea is to eat enough food to provide adequate energy until the next meal.
When the body is going through metabolic changes, sufficient rest is critical. A person should get at least 7.5 hours of sleep during each of the three days. During sleep, the body's hormone levels that control appetite become active. Without sufficient sleep, the body may require additional food to carry out metabolic processes.