A lot of paleo thinkers seem to be rather sceptical of plants by default, preferring to 'eat food that can't defend itself after it's dead,' and assuming that plants are essentially out to get us, using whatever chemical means they can to stop us eating or fully digesting them. At the same time, many paleos think that select fruits and vegetables can be part of a healthy paleo diet and indeed part of the optimal paleo diet.
The historical evidence is much debated over, modern day hunter gatherer diets seem mixed. What I'm interested in working out is which plant foods- if I'm going to eat any at all- would be the safest candidates for staples of my diet. Tubers are a natural suggestion, but potatoes are related to nightshades and contain glykaoalkaloids, sweet potato contains cyanogenic glycosides. Leafy greens like spinach might seem to be a natural foodstuff that would be plentiful and easily gatherable throughout our evolutionary past, but they are full of oxalate and rubiscolin. Crucifers like cabbage, brocolli, kale etc are notoriously healthy, but are goitrogenic. Most fruits seem safer, but on the other hand are far more full of fructose, one of the most anti-paleo substances there is.
So the main things to consider seem to be:
- Which foods are safe, or can be made safe by certain treatments, from the point of view of anti-nutrients?
- Which foods are optimal from the point of view of being made up of starch (which needs to be processed but yields glucose) versus fructose?
- Ought we to favour foods like berries which are packed with 'phytonutrients' and antioxidants or should we be wary of these plant chemicals?
Obviously the thing that ultimately counts is the hard physiological analysis of each of the respective chemicals, but since the data here would be ludicrously expansive and detailed, I think a paleo perspective on- what would we actually have evolved to eat?- is particularly useful.