How do you gain 20lbs in 8 weeks?

Don't eat just fats you will gain but also you get in a habit of eating them. What to do is probably start eating very little fatty foods but still excersise if I was you I would ask a doctor or someone and if your consernd about your money either ask him over phone or google it. Hope this helped! (Also see the answer to an earlier question about losing weight - see link - and reverse the calorie recommendation. Note that increasing your intake by 250 calories per day under this scheme should achieve the result you seek. Health issues are also discussed.)