I was raised by a mother who introduced me to a semi-weston-price diet(ie lots of visits to restaurants offering wild stagmeat/wild boar meat etc., plus her home-cooking was pretty good as it included lot sof (cooked0 organ-meats, so, by the standards of modern diets, it was pretty good. Food at private school was bad, but what made things worse was that dairy was widely available at school and at home( as was bread). The result was that my health deteriorated over time - all because general modern dietary guidelines all heavily recommend dairy as a health-food when it is a pure poison for many. If I'd never touched dairy in my entire life, I suspect that I would only have started deteriorating, healthwise, from the age of 40(I would still have had issues with some processed foods , though, such as additives/chemicals etc.)
That said, my family members have pretty much started deteriorating after the age of 40, some before that point. My oldest brother had an accident with an electricity-wire causing the loss of both his feet so that he needed artificial legs. He was in great pain for the rest of his life, having to take pain-killers and various drugs(eg:- cannabis etc.) to kill the pain. He died at the age of 28 as a result of an accident, not as a result of his injuries, though.
Then there's my doctor uncle:- He openly sniggers at my diet, yet at the age of 68/69, he's in appalling shape. His joints are so f*cked that he had to, on one occasion, crawl, like a baby, up the steep steps of my Italian home when returning from the beach, because he'd forgotten to take his pain-killers. He also, like all of his generation, has to take endless artificial supplements to make up for the deficiencies in his so-called balanced diet. His daughters are in their 30s and all 3 of them had their beauty fade very quickly after the age of 20 or so, the result being that they tend to overuse make-up. Normally, women only have their skin deteriorate re wrinkles etc. at the age of 30, but, no doubt due to eating processed diets and bad genes, they deteriorated faster than others. Same goes for their mother who goes in for huge numbers of supplements such as coenzyme q10, but these have done nothing to slow down her aging.
My mother is in better shape than my uncle(her brother), even though she's older than him by 7 years. However, the primary reason for this is that she loves starving herself, practising caloric restriction. She also eats lots of plant-food(cooked minimally) which helps avoid the buildup of toxins caused by eating lots of heavily-cooked fat-heavy animal-food.
My other aunt and uncle are both riddled with cancer and are mostly vegan. Their daughter is quite healthy for her age(49?) with their son's family having childhood asthma etc., because the son's wife insists on smoking heavily and taking her kids to McDonald's all the time, because she hates cooking etc.
Oh, yes, and my father died at the age of 70, hugely obese, and riddled with diabetes, dying of a heart-attack.. He ate the usual bad foods such as grilled meats, potatoes etc.