Fast weight loss: What's wrong with it?

Why do doctors always recommend a slow rate of weight loss? What's wrong with losing it fast, if you can?

- Eduardo / New Jersey

Mayo Clinic physical medicine and rehabilitation specialist Edward Laskowski, M.D., and colleagues answer select questions from readers.

Answer

When it comes to weight loss, slow and steady wins the race. Fast weight loss is usually followed shortly by rapid weight gain. Besides, 1 pound of fat contains 3,500 calories, so you need to burn 500 more calories than you eat each day to lose just 1 pound a week (500 calories x 7 days). If you're losing more than 1 to 2 pounds a week, it's either water weight or lean tissue you're losing, not fat. Weight loss of 1 to 2 pounds a week may seem like an agonizingly slow pace, but if improving your health is a long-term goal, the speed of your weight loss isn't important.