The length of time to lose belly fat varies with each individual and how much fat there is. In order to lose 1 pound of fat, a 3,500-calorie deficit must be created and maintained. This means that 3,500 more calories should be burned than are consumed.
Metabolic rate and additional physical activity dictate how much and how fast calories are burned. Nutritional habits affect how many calories are consumed. Creating a 500-calorie deficit per day results in the loss of 1 pound of fat per week. According to the Mayo Clinic, excess belly fat increases the risk of cardiovascular disease, type 2 diabetes, sleep apnea and colorectal cancer.