Physical fitness and Food

Salamualaikom,

I read that RasulAllah (sallallahu alaihi wa salam) and many of the sahabah were physically big and muscular, but they would eat a minimum amount of food. How can someone like myself do weight training or cardio while following the sunnah of being hungry? I want to retain the strength and physical stature but at the same time eat maybe once or twice a day.