I merely cited cassava as it was the most toxic cited among those many tubers which need to be throughly cooked and processed.Cassava is known to routinely cause cyanosis etc. There are, of course, some tubers which are probably low enough in antinutrients to be edible without issues, and then there are those many tubers which are just barely edible but which are high enough in levels of antinutrients so as to not be truly suitable foods at all. The way I see it, in order for humans' digestive systems etc. to be designed to eat tubers in general, we would have had to be very similiar to paranthropus boisei in terms of having massive jaws needed to masticate tubers properly etc. Plus, the very fact that some tubers have to be cooked in order to be edible does strongly suggest that they were not a significant part of the hominid diet until after the advent of cooking, and even then likely only after the Neolithic when agriculture came into being.
The point is that our bodies are not well designed to deal with the antinutrients found in plants like tubers. A herbivore usually has several stomachs and countless extra enzymes etc. which are all needed to properly digest such items in full. The antinutrients block uptake of nutrients plus the tubers are low in nutrient value anyway. I do not deny that tubers are seen as fallback foods. Indeed, after a little more checking
, increasingly, Nutcracker Man and other hominids are cited as using tubers only as fallback foods when other foods were not as available, or not really eating tubers at all, eg:-
However, research on the molar microwear of P. boisei[8][9] found a microwear pattern very different from that observed for P. robustus in South Africa which is thought to have fed on hard foods as a fallback resource.[10] This work suggests that hard foods were an infrequent part of its diet. The carbon isotope ratios of P. boisei suggest it had a diet dominated by C4 vegetation unlike P. robustus in South Africa.
taken from:-
http://en.wikipedia.org/wiki/Paranthropus_boiseiSo we have a long period of increased meat-eating and less plant food in later Palaeolithic times, and likely only minimal tuber-consumption in the hominid given recent findings such as above.
I doubt that cooked tubers were the culprit behind diminished brain and body size. Grains are more likely.
What I have established, though, is that tubers could not have been responsible for greater hominid brain-growth as increased meat-consumption(and, logically, by extension, decreased tuber consumption) was shown to be responsible for that.
Given that tubers are starchy foods like grains, really the only difference between them is that grains, even when cooked, contain even more antinutrients in them compared to most tubers.
Just goes to show, one should never take anything other people state for granted, even if it sounds plausible or backed up by scientific data, as more recent data can debunk older data easily, given new evidence.
