Being kidnapped and held for ransom by Somali religious fundamentalists usually does the trick.
eat proper size portion meals and exercise 30 mins a day... same way doctors have recommended for the last 50 yrs
Date a vamp or lycan.
Cheesy as it sounds, but eat all of the food grounds, eat in moderation, eat a bunch of small meals/ snacks a day instead of three big ones, and exercise !!
Exercise, eat less fattening foods, and drink water.
Proper diet and exercise.