How to begin an effective fitness + diet regime?

I am 14 years old, weigh a little over 120 pounds, and in my eyes, I'm too skinny and weak. I hardly ever put on weight and trust me I eat lots, mainly junk food! I used to play a lot of competitive sports, but now as I've moved up into high school, I've become very lazy! Now I am very unfit and I tire easily. I need to begin and effective fitness + diet regime straight away, or I will probably end up living a very unhealthy life!How to begin an effective fitness + diet regime?At your age I would suggest that you start playing sports again, then you can get fit and enjoy it. Join your local football. cricket, rugby, athletics, hockey, swimming, tennis, basketball, softball, squash, etc etc. Whatever sport you fancy.How to begin an effective fitness + diet regime?eat loads of protein, use weights and go to the gym weekly. this will improve your muscles and boost your weight How to begin an effective fitness + diet regime?Go checkout http://www.cagedanimal.net post your question in the beginners cage and you will get tons of relative info and support.