In my mind, diet and exercise are THE key components of a long and healthy life! Certainly, genetic disposition is a factor but (currently) there's not much that will change that factor. I think it's important to note though, that many genetic dispositions ("good" or "bad") can be overridden! Many of us have seen how individuals with high levels of athleticism, health and/or beauty, can spiral down to become a "hot mess"! I'm sure that this is mostly related to neglecting the key components of diet and exercise. I believe the opposite is also true only it's less news worthy so it's brought to our attention less.
Cycling (as many here have pointed out) is a great way to provide the exercise component! RE: Diet, I've found (but this varies to each individual) that reducing carbohydrates (especially those with a higher glycemic index), increasing protein and moderating fats, works well for me. High fiber foods are important as well as hydration.
The internet is awash with "the best way to..." but it all boils down to eat right and exercise!