Climate does make a difference, for sure. But there are two things to consider. One, climates that are warmer let things rot easier but tend to have longer or continuous growing seasons. Two, climate control is a thing that people do (dig deep enough and you get cooler temperature almost anywhere on Earth) as is processing for storage via drying or chemical treatment.
Forgot to mention nuts too.
You are certainly right about protein. Something else must be added, be it meat or veggies of some sort or legumes.
nuts
Hm, interesting. I don't know of any culture which heavily relied on nuts as a food source. I wonder why that is so. Nuts are excellent food -- fairly complete nutritionally, high caloric density, don't spoil easily, etc. Moreover, they grow on trees, so once you have a mature orchard, you don't need to do much other than collect them. One possibility is that trees are too "inflexible" for agriculture -- if your fields got destroyed (say, an army rolled through), you'll get a new crop next year (conditional, of course, on having seed grai...
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