Twenty pounds in 3 months!
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Holy crap!
alcohol = 7 cal/gram
fat = 14 cal/gram
The best you can do is to follow Duper's advice on nutrition and exercises getting your heart rate up, like jogging or bicycling.
Weight lifting can reduce your weight if exercised intensely and if you're not eating excessively, but endurance sports is better.
If doing that, keeping your heart rate in the \"fat burner\" area (depends on age, sex and fitness) will burn a higher percentage of fat compared to carbohydrates, but doing cardio training still can burn more fat absolutely.
A simple example (wrong numbers, just for the principle):
fat burner = 30% fat, 500 kcal/hour -> 150 kcal fat/hour
cardio = 25% fat, 1000 kcal/hour -> 250 kcal fat/hour
So if you're fit enough, doing cardio wouldn't hurt. Btw, if you are doing a lot of cardio training over a longer period of time, the fat ratio will increase.
Ofc complementing endurance training with some weight lifting can give you some nice muscles.
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Be careful not to exhaust yourself so much with weight lifting (because the effect is visually more appealing) that you cannot do proper endurance training.