Fresh, natural, UN-PROCESSED food is vital. Why?  To provide every cell in your body with all the essential nutrients so that every cell can function efficiently.    Avoid processed & refined foods (ie anything that has additives, anti-fungals, dyes and chemicals etc). Eat a broad range of foods in your diet. 

The principle of good nutrition is to maintain dietary diversity. Vegetables & fruit from the red, orange, green, yellow and white varieties, and natural grains and cereals.  Lots of fish. Lean meat.

Consider the perfect Palaeolithic Diet               versus  The modern process refined carbohydrate diet.