It's possible to lose weight in three weeks by eating a healthy diet and exercising, according to WebMD. By taking this approach, some people lose up to three pounds per week.
Individuals who burn 500 more calories a day than they consume can lose one to two pounds in a week. To increase this to two to three pounds, eating 1,050 to 1,200 calories and exercising for an hour is necessary. Weight loss levels aren't guaranteed in each person, but taking this approach is a healthy way to lose weight in three weeks.
For fast but healthy weight loss, eating fruit and vegetables, lean protein and nonfat dairy foods is essential. In addition, reducing sugars and foods high in fat is helpful. Individuals who stay active and keep track of their eating habits are more likely to lose weight. This includes avoiding boredom, which often leads to snacking.
Exercising for at least 150 minutes per week encourages weight loss, Mayo Clinic states. In addition, increasing physical activities in and out of the home is helpful; for example, cleaning, walking to work and shopping. The more physical activity a person engages in while eating a healthy diet, the more weight she loses. However, exercising too much on an extreme low-calorie diet isn't healthy and doesn't lead to sustainable weight loss.