Of course the solution is to conduct an active and healthy lifestyle. Eat properly, exercise regularly, have enough rest, think positive and be wise so that you can avoid getting yourself into problems that make you feel depressed. It's the healthiest long-term natural solution.
Never hope you'll get your dream body just by taking meal replacement or worse, not eating at all. The effect is not long term, plus it weakens your body
Yea I know the greatest challenge to this is to discipline one's body and mind, and to know the correct technics. Just don't be too harsh on yourself. Even a fitness instructor like me cheats sometimes