The importance of diet cannot be underestimated. You are what you eat. I have always made sure to consume large portions of vegetables and will cook fresh most of the time.
I have peaks and troughs, but mainly do pretty well with it. People have consistently, and still underscore my age by 10 years as a minimum.
Conversely I see pictures online of people I went to school with and they have clearly lived off beige junk food their whole lives. A couple I can think of right now, they would easily pass for 10-15years older, same age as me.