Let me do a good deed today.
Reason most people are gaining fat is because they eat more calories than their body can burn. 1 lbs of fat = to about 3500 calories. Therefore it is hard to burn fat but also hard to put on.
There is however a good way to burn fat and that is to eat less and do more cardio.
To calculate how much calories you should be taking a day, take your body weight in lbs e.g. 120 and multiply it with the number of hours you workout per week + 9.5. So that should be about 120 x (9.5 + 3) if you work out 3 hours per week. 1500 calories. So if you maintain at 1500 calories per day, you basically will stay at that weight of 120 lbs.
A person normally burns of 10 calories per pound. So if i weight at 130 pounds, my body basically burns off about 1300 pounds. So if i want to get down to about 120 pounds, and i workout for 3 hours per week, my body burns 1500 calories and I'm only eating 1200 calories so i got a calorie deficit of 300 calories. 300 x 7 = 2100 calories. So basically I'm going to burn 1 pound of fat every 2 weeks and it gets harder as my body fat percentage goes down because I weight less.
Hope you get the idea...
P.s. TO GIRLS ---> Don't be afraid of working out because the posibillity of you packing muscles are very very low because girls lack testosterone if I'm not mistaken but still girls very hard to build muscle. So workout more and do more cardio to lose fat.
Get lean by dieting hard and exercising hard.