How long it takes to lose 20 pounds depends on the rate of weight loss, generally 0.5 to 1 kg per week is recommended, so 20 pounds will take about three to five months. Weight loss needs to be gradual and at different rates for different individuals. Generally speaking, healthy adults who have a high body mass index are recommended to consume 1200 to 1500 calories per day and lose between 0.5 kg and 1 kg per week, so it takes three to five months to lose 20 pounds. The above rate of weight loss is already faster and can only be done at this rate if there is no underlying disease. If the combination of underlying diseases, such as diabetes, hypertension, high blood pressure, weight loss needs to be carried out under the guidance of a doctor, because of the risks associated with weight loss in this group of people, especially diabetic people, excessive weight loss is easy to induce hypoglycemia, resulting in aggravation of the disease. Weight loss is a long-term process, and should not be rushed, otherwise it is easy to rebound, and accompanied by great health risks.