Problem is figuring out which behaviors, and which foods not to eat.
Boom - you've just covered most of the risks that you can control.
This is one of the more fascinating recent discoveries about diet, that anti-oxidants can actually CAUSE cancer instead of prevent as previously assumed.
Obviously the jury is still out, but we had thought the jury was not out until recently.
There's a reason chemophobia is a thing - most of the chemicals in household products are not tested, and many of them are suspected carcinogens.
Obviously it's not necessary to go all the way to chemophobia, but a little caution would not hurt.
Your grandparents and parents provide a good real-world "preview" of the possibility(s) that genetic make-up might predispose one to certain infirmities, illnesses, cancers...
Maybe you should be on guard against those evidenced, to the extent possible...after all, you're very much like them...?
Did they live a life that eventually led to any medical conditions they experienced...?
Should you avoid the life choices that they made...?
https://en.wikipedia.org/wiki/Breakfast#Effect_on_health
I'm also reasonably sure that the hearty English breakfast is older than Kellog's cornflakes. As is the Japanese breakfast with grilled fish and rice and the traditional breakfasts of countless other cultures.
Reinagel also suggests that link between skipping breakfast and increased weight may be mostly behavioral – compensating with snacks and eating more later—and therefore not inevitable