There are many aspects to maintaining your health, we cannot address just one and expect the others to just fall into line. But if we can get one performing better the others will show improvements too.
Physically we must be active and move our bodies around, this stretches tissues, circulates fluids like our blood and lymph. Blood brings nutrients, delivers hormones, essentially feeds every area of the body, lymph carries away the by-products. Moving our bodies through their full ranges of motion help to ensure that blood and lymph reach every tissue.
The fuel we use is another important aspect. What we consume, the by-products of that fuel, the timing, frequency and volume of food are all key factors to maintaining health. Making sure we are only consuming the fuels we need is also key. Some of the things we crave are clues that we are deficient in a mineral or nutrient instead, but it is easier to say 'I crave chocolate' than to say 'I crave Magnesium and should therefore have nuts/seeds'.
Taking care of ourselves mentally is another vital part of health. Recognizing good and bad thought patterns, triggers for each, and managing them properly. If you feel that you're having a thought pattern that you can't break, talking to a professional who can give you tools, help you find the root source of that thought and break the cycle is incredibly valuable.
These three are just a few of the vital systems that all need to be functioning. It never ceases to amaze me how what I eat affects how I think, or how I move affects the food I choose. Full body health is a multi-dish balance scale, change one and they all are affected.