Adopting a new, healthy lifestyle that includes regular exercise and a low-calorie diet is the key to fat loss. Rapid fat loss, however, isn't practical. Losing weight at a rate of 1 to 2 pounds per week is a realistic, healthy goal, according to the Centers for Disease Control and Prevention. If you wish to lose belly fat in five days, it's possible to lose a nominal amount of fat from this area, but not likely enough to be noticeable.
You Can't Target Your Belly
It's impossible to choose the area of fat on your body that you burn. The theory that you can do so, which is known as spot reduction, is a prevalent myth in the weight-loss community, notes CNN Health. Thus, even if you're able to put your body in a calorie deficit over the course of five days -- perhaps even to the extent of losing a pound -- this fat loss is distributed around your entire body. The fat loss you'd experience from your belly would be just a fraction of a pound.