I'm about 5"10 I weigh 165 lbs and I'm an 18 year old guy. I am also doing weight training, my question is that how much cardio do I need per week? I was told that too much cardio may use up muscles and there is a way where you only target fat. Is it true and how can I achieve it?
Have a nice day,
At 5'10 and 165 you couldn't have a lot of fat to lose, so my suggestion is that you concentrate on gaining muscle by weight training and keep cardio to a minimum. But use your diet to build muscle and lose fat by increasing your protein intake and lowering your carbohydrate and fat intake.
For more info checkout the Guide to Building Muscle while Losing Fat