Growing up in the 40s/50s/60s, I ate a home-cooked diet including roast heart, liver and onions, steak pies, bacon, sausage and a range if meats and fish. No snacking but always a proper hot breakfast, cooked 'dinner' and pudding and cooked 'tea' with pudding. Supper was cocoa, Horlicks or Ovaltine with a biscuit or two.
In my late 20s I decided not to eat meat, game or fowl and the only fish I eat is cod and haddock. I've never eaten shellfish.
Eat plenty of veg (but not sweetcorn/kale/fennel) pasta, full fat cheese/milk/yogurts/butter/artisan breads (not white) and occasionally eggs. I like good chocolate too.
Although mum died of bowel cancer and dad died in his 40s of atherosclerosis, I count myself lucky to be healthy: no health problems or meds and never have needed any, no ops, 5 children normal deliveries no problems, and my excercise is, I guess, just walking.
3 times a year over 43 years I've donated blood which rules out anaemia. Don't have hearing or eyesight aids but I do like lots of sleep and fresh air. I'm guessing that health is not exclusively genes or diet related, just the luck of the draw.