You have to demand it by doing exercise, and eat regularly so your body doesn’t think it’s being starved. Not only did I lose weight by eating slowly, by focussing on the food with no distractions (TV, etc) and eating more often, but because I ate less food, I had more energy because my body went into a state of being ‘ready’ to ‘go and get’.

Also, don’t masturbate too often if you’re a boy. Much of your inclination derives from ‘wanting sex’. It’s not as enjoyable unless you really need it anyway. Restrict it to before sleep.