One thing that would go hand-in-hand with seasonal variations, and eating what your ancestors typically ate (which does not include vegetable oils)… is problematic, in that the human species is so mixed and displaced now… i.e. Scandinavians that live in Brazil, traditionally did not have access to lots of fresh fruit… and now can consume it year round. For some that might be fine, for others, not so much.
That’s where listening to your own body comes in…
I get a box of organic, seasonal veggies delivered to my door twice a month – so I do eat seasonally, and love the variety… but the selections are from things available this season from BC Canada to Ecuador… so… not sure how that fits in with things.