Every individual is different, but the consensus appears to be that if you eat more natural foods, in their original state with minimal chemical interventions required, it appears to have the best overall effect on your health.
My diet is mostly Mediterranean based (Greek heritage) and that seemed to help quite a bit. We only used olive oil at home, mostly cooked our own meals, and avoided heavily processed foods. In adulthood, I (mostly) follow the same philosophy.
Indeed. When I was diagnosed with cancer I started on a diet to "eat more natural foods, in their original state with minimal chemical interventions required," -- local grown/raised produce, minimal pesticides (organic, non-GMO (glyphosate exposure linked to Non-Hodgkins Lymphoma)), etc. and I do believe this has helped.
Enjoy