I WANT TO LOSE WEIGHT ! 10 POINTS?

My boyfriends is going out of town for 3-4 weeks and I want to lose weight while he's gone. Maybe15-20 pounds, I don't care if it's NOT healthy, being 5'7 216 is NOT healthy so KEEP the BAD comments to your self okay? and how long should i jog on my treadmill? elliptical machine? & stair master machine? on my rest days I will walk a mile & for break fest yogurt & wheat toast. snack: large apple lunch: sand which with baked chips & snack: sugar fee jello or pudding & dinner: salad or baked chicken with green veggies ! is this a okay diet? I need to lose 15-20 pounds in 3-4 weeks & I know I won't gain it back ! only positive answers that are NOT against me ! thanks (: