Yes to that, except that we eat animal foods that are in season. Some fatten at different times, some dairy is better than at other times. We don't eat much produce.
I have a hard time imagining maintaining a metabolic equilibrium by eating *lots of cruciferous veggies* this month and *lots of sweet ripe fruit* this month and so on. Even if one accounts for the natural varieties of carbohydrates produced at harvest seasons to correspond to climatic changes, vegans and vegetarians know the importance of a variety of fresh high quality produce year-round to make the diet sustainable. The 'cheats' used by cultures without fresh produce year round are using preserving minerals (some self-contained, such as sun dried chilis) and using concentrated animal fat - such as fish broths the smell of which would probably make an American retch
but which keep for years without refrigeration and contain every nutrient the diet lacks without harvest fruits or even eggs & milk (not available year round either, in the natural environment).
So I guess I can see how this is possible by eating a modest, high quality animal-based diet, but otherwise I have doubts.
What has your experience been?