HOW CAN I LOSE 50 POUNDS IN 7 WEEKS?

I dont care how unhealthy it is I just wanna know what should I do? No diet pills or liquid diets. Just eating veggies, fruit & lean meats. & yes it's possible, because my friend did it with weight watchers but lost the weight in 6 weeks & it stayed off for a while & still is ! I'm 5'7 216 pounds & It's for school ! (: thankss && oh how long should I jog/run on my treadmill ? elliptical machine & stair master? & what should i eat? I start my diet next week