If you eat crap, you will feel like crap. Your body is a machine. Fuel it with real, whole foods as much as possible. Hint: that won’t come in a box. The only effective exercise plan is one that you can stick to. Find something you like to do and keep doing it. Your body will adapt so continue to increase length and/or intensity to avoid plateaus. Don’t commit yourself to something you hate and a schedule you can’t maintain.