Your body is designed to be healthy. Given a chance the body is a self-healing, self-regulating system. All the body needs to express full health is for you to provide it with the essential raw materials and not to add anything harmful. The building blocks of health could arguably be divided into 3 categories:
1) a nutritious diet,
2) adequate physical movement
3) A healthy psycho-social environment.
Ultimately you decide your future health by the lifestyle choices that you make today.
Diet, what to do:
Essentially eat a diet based on what you naturally could find living in the wild (there is plenty of space for personalisation, to best suit your philosophy and needs) e.g.;
1) Grass feed mammals, fowl, eggs, wild caught fish.
2) Eat 5 vegetable servings/day.
3) Also include some fruit, nuts, seeds and berries preferably locally grown and in season.
Avoid eating: Processed food (Esp. refined: sugar, vegetable oils, wheat and other grains).
Movement, what to do:
1) Light cardio and mobility training at 55-75% of max heart rate 2-5 h/w.
2) 7-60 min of resistance training 1-3 times/w.
3) Max effort sprinting once every 7-10 days.
Avoid chronic sitting or other highly repetitive work tasks and postures.
Psycho-social, what to do:
1) Full night sleep in sync with the day/night cycle
2) Spend quality time with family and friends
3) Spend time playing and developing your passions
Avoid: Social isolation, job-dissatisfaction, and negative personal relationships.