How can i lose 40 to 50 pounds a week?

Amputation: There is no safe way for anyone to lose that much weight that quickly. Diets that promise huge early lossess often rely on water shifts and loss as starting--but for 40-50 lbs, that would be 5-6 gallons of fluid and would get you into an icu. Safe weight loss in general is 1-2 pounds/week. Younger males can do 3-5, but even medically supervised diets can't deliver what you are asking.