I don’t think wikipedia is useless. I found a brilliant article entitled “Pleistocene Human Diet”. It covers our early human ancestors like neanderthals, heidelbergs, as well as homo sapiens. Fascinatingly, in the section on homo sapiens, the article highlights the fact that increased brain size and decreased gut size is correlated with the advent of fire because this was a critical innovation that allowed for the digestion of starches otherwise inedible. Incredibly, they go on to note that key distinction between our closest extinct relatives the neanderthals and homosapiens is the ability to digest cooked starches. Even more incredibly they note that tubers were critical to the diet of the prehistoric peoples! If that’s not bad enough, it says that the key role of tubers was food stability throughout the year. I was just speculating when I was saying that stuff above because it made logical sense to me, but apparently I wasn’t too far off. It looks increasingly likely to me that our ancestors were tuber rooting omnivores…
Here is the section on Homo Sapiens:
Homo sapiens 
The evidence of early Homo sapiens diet stems from multiple lines of evidence, and there is a relative abundance of information due to both a larger relative population footprint and more recent evidence. A key contribution to early human diet likely was the introduction of fire to hominins toolkit. Some studies indicate a correlation with the introduction of fire and the reduction of tooth and gut size, going so far as to indicate their reduction as clear evolutionary indicators of the widespread introduction of fire.
A key difference between the diets of Homo sapiens and our closest extinct relatives H. neanderthalensis is the ability to effectively digest cooked starches, with some evidence found linking cooked starch and a further increase in H. sapiens brain size. Roots and tubers were introduced into the broader human diet, and can likely be assumed to be associated with fire as cooking would likely be necessary for many tubers to be digested. The use of root and tuber species in some Hunter Gatherer cultures makes up a critical component of diet. This is not only for the nutritional value of the species, but the relative annual stability of the species. This buffer effect would be important for many groups that relied on tubers. The ability to process starch is linked genetically to modern humans, with the genes necessary to its consumption not found in H. neanderthalensis . The timing of this mutation on modern humans is important as it means the ability to digest heavily starchy foods has only developed in the last 200ky years.