I agree with Nance regarding the "fruity fallacy" (trademarked term FYI). Despite our own homo sapien-centric view of the world, fruit was not created for the sole purpose of our pleasure. Long before we walked this planet, there were large frugivorous mammals (megafauna) that had a mutualistic relationship with many tropical and sub-tropical fruit-bearing trees, shrubs, etc. In order to ensure that their seeds would be consumed and dispersed (shat out), the fruits that they produced needed to be palatable (i.e. sweet) and large enough to attract attention.

(http://www.plosone.org/article/info:doi%2F10.1371%2Fjournal.pone.0001745) .

But I digress.

We split from chimpanzees when we desided to trek out into the semi-arrid grasslands where fruit would have been less plentiful (chimpanzees are still primarily frugivorous although they do eat insects and hunt small-game, something that we would have likely continued to do as we were able). In this environment, we may have developed some of the thermoregulating adaptations that separate us from other primates (naked skin, sweat glands, upright posture, etc.)

In this environment, we would have had access to larger game, something that afforded us the luxury of smaller guts and larger brains. There is strong evidence that the first stone tools were used to break open bones, and to butcher large herbivorous animals. So, we can definitely assume that bone marrow, animal fat and offal, and some "lean meat" was part of the ancestral dietary.

Additionally, this landscape would have supported plant species that stored energy and water in the form of tubers. As we can see with modern hunter-gatherer tribes that still inhabit areas in East Africa, such foods are often dietary staples.

As humans traveled out of Africa, we migrated East along the now-submerged coastal areas of Eurasia all the way to Australia. During this time, we very likely took advantage of coastal resources such as shellfish. Technology may have also developed to the point where we could spear larger fishes. (The advancing of the oceans at the end of the last ice age has hidden the physical evidence of this aspect of the human migration out of Africa.)

From here, we began to push North along rivers and tributaries. We may have followed reindeer and mammoth herds through central Asia into the Americas, and would have depended on animal products (furs & skins especially) to even survive in such environments.

Our dietary would have remained relatively unchanged (area specific animals, plants, bugs, fish, shellfish, tubers, & fruit) until the emergence of mutated cereal grasses (modern wheat ripens all at once whereas primitive forms would have matured at different rates, making an organized "harvest" impossible) and domesticated animals that mark our departure from the Paleolithic.

As always, I must stress I am not a qualified expert, merely an interested reader. Within the inquiry of which fruits ancient humans of Africa may have eaten I found the following. I'm interested in more non-paleo sources on both sides of the issue.

At Raw Food SOS and yes, I also check out non-paleo sites too, is an interesting reference:

"...Although not all wild fruits are as big and sweet as our modern cultivars, at least some are, and certain varieties even surpass our deliberately-bred fruits in size and flavor. Nature—especially with selection pressure from other fruit-eating creatures—is perfectly capable of producing sweet (and sometimes massive) fruits without human intervention. It seems unlikely that early humans only ever encountered berries or other “small, bitter” fruits, and avoiding sweeter fruits on the basis of evolutionary history may be misguided. Based on the limited research we have, wild fruits aren’t considerably different from cultivated fruit in terms of carbohydrate content, fructose content, or fiber content. Both wild and cultivated fruit seem to average around 90% of calories from carbohydrates, and have a sugar composition that yields roughly equal parts glucose and fructose. And both wild and cultivated fruit can be relatively high or low in fiber. Although berries are often lauded as being lower in fructose compared to other fruits, from a calorie/energy standpoint, this just ain’t true! Early humans may very well have had access to fruit for most or even all of the year. The fruiting seasons we witness in cooler climates—with most fruit appearing in the summer—doesn’t necessarily apply to our evolutionary homeland closer to the equator..."

Two references cited in the post are Fruits of Warm Climates by Julia F. Morton and Lost Crops of Africa: Volume III: Fruits.

I will not miss this opportunity to once again post this URL:

http://tinyurl.com/3jqbmuo

I will pester y'all with that link to the end of my days, or until y'all scream "Enough, already - it's brilliant!", whichever comes first.

That sceario of hominid evolution is the only one that explain all our human idiosyncratic physical characteristics.

And it's completely carnivorous.

I found this to be very helpful:
http://www.beyondveg.com/nicholson-w/hb/hb-interview1c.shtml

And a good (but very dry) book to check out would be Food in Antiquity by Don Brothwell

I lifted the following from a previous post I made some time ago and pasted it here (with some minor editing) because it seems to have relevance to this discussion of the availability of carbs and specifically ancient fruits. Here it is -

We came out of the Pleistocene 11-12,000 years ago at the end of the last glacial period. The beginning of the Pleistocene is roughly 2.5 million years ago and the Pleistocene itself roughly coincides with the advent of modern hominids. This would be our beloved paleo era. During these periods of repeated glaciation Africa was a very dry place, so much so that the African woodlands retreated to just three small patches during glacial maxima and there was broad expanse of African savannas and grasslands. Not much fruit or tubers in grassland (and I say this because I've been in grasslands), but the important part is coming up.

The earth's eliptic plane changes seasonally in relation to the sun, but we all know this. The north pole is sunny in summer and dark in winter, etc, but the surface of the earth closest to the sun near the equator keeps moving in cycles above the equator and then below the equator and so on. That surface gets direct perpendicular heat from the sun causing the humid air to heat up and rise to altitude which causes the air to cool and condense into rain. So as the changing eliptical plane of the earth moves up and down in relation to the sun, the rain likewise moves above the equator and then below the equator and these are the monsoons. As the monsoons move north then south, then north, then south, hoofed animals follow these rains and these are known as the great migrations.

I mentioned in an earlier post that paleos were nomadic because they chased after game when an area became depleted, and because they went high in summer and low in winter. Well this is another reason. They followed the hoofed migrations because they were going where the food was going.

I'm not sure how long this went on but you had the better part of 2.5 million years to get this pattern established and when you see illustrations of paleo people out in vast grasslands, this is what you are looking at. Most of this pattern was established before humans migrated out of Africa. So as I said before, the African woodlands retreated to three small patches. Before this happened there was one main species of gorilla. Here is the diet of the herbivorous gorilla -

*The diet of a gorilla consists primarily of fruits, leaves, shoots, shrubs, vines, tree bark, flowers and a variety of other plant matter. http://www.ehow.com/about_4580393_gorilla-diet.html*

Originally gorilla habitat was broad, as broad as the woodlands use to be. As the woodlands shrank, the supply of gorilla feed and fruits (and habitat) shrank with it till there were separate groups of gorillas which eventually diverged into subspecies. (See Children of the Ice Age by Steven Stanley)

If the available gorilla carbs dropped to such low levels, so low that the gorilla couldn't thrive and almost died out retreating to small patches, and yet nomadic humans were traipsing north and south thriving on animals, and this went on for most the Pleistocene, where is the evidence that carbs had anything to do with this? They were relatively rare which resulted in gorilla die-back. Grasslands are not carb friendly, especially year round, yet the hooved animals were capable of converting grass into protein and fat.

Today in Africa, most of that rainforest has recovered since the end of the last ice age, but the gorilla populations have not reestablished contact (and probably never will in today's Africa). But as the forest recovered so did the supply of fruit and this is what we see today.

The pattern of aridity/humidity in Africa across glacial-interglacial cycles is vastly more complicated than various people allude to above. There's no simple glacial=arid rule that can be applied. But that's by-the-by. One of the most recent relevant papers on this topic is: Thomas and Burrough (In Press). Interpreting geoproxies of late Quaternary climate change in African drylands: implications for understanding environmental change and modern human behaviour. Quaternary International.