No matter what im not reducing weight. I tried dieting, but no. Exercise, age 20...weight is 70. I need to loose weight quickly.

Doctor can evaluate. Anything that uses energy (calories) will help one lose weight, as long as he DOES NOT eat or drink back more calories than used, after the activity. If walking, take a longer route; use stairs instead of elevators; take multiple trips to and from the car when unloading groceries; park a block from school and walk there with the kids; at home, skip dessert and go walk around the block instead.