Individual needs vary, but the Mediterranean diet is a great place to start: https://en.wikipedia.org/wiki/Mediterranean_diet

> The Mediterranean diet is associated with a reduction in all-cause mortality in observational studies. There is evidence that the Mediterranean diet lowers the risk of heart disease and early death. The American Heart Association and American Diabetes Association recommend the Mediterranean diet as a healthy dietary pattern that may reduce the risk of cardiovascular diseases and type 2 diabetes, respectively.

It varies slightly from person to person, but generally “lots of vegetables and minimize highly processed foods. Those are the common denominators of a healthy diet. From there, you can fill in the blanks to suit your tastes and your unique physiological needs by adding your choice of high-quality fats (nuts, seeds, avocados, olive oil, fatty fish), carbohydrates (whole grains, fruit, starchy root veg­etables), and plant- or animal-based protein (legumes, soy, fish, lean sustainably raised meat, poultry, eggs, dairy).”

https://www.health.harvard.edu/staying-healthy/what-does-a-h...