According to http://en.wikipedia.org/wiki/Paleolithic_diet#Fibre_content_and_glycemic_load we eat "potentially as high as 1.65 to 1.9 kg/day.".
That sounds really high, or isn't it?
Perfect Health Diet says:
I don't think we eat 3kg of food per day. About 800g of vegetables seems more likely.
High-fiber plant foods are mostly there for feeding your gut flora. We're not gorillas so we don't have a lot of gut to feed. Your gut flora will then convert some of it to short chain fatty acids which are beneficial.
If you eat a lot of fiber however, you're upregulating the activity of your gut flora, which also upregulates the toxins they release. This is balanced by our immune system that then tries to kill off some gut bacteria. This is of course an inflammation. So fiber is good but too much fiber not so much.
The 1.65kg figure comes from 1998 Cordain paper based on a 'model' using a statistical rather than realistic diet and assuming 65% of calories from plants. And is for a 3000kCal diet. The paper seems to acknowledge how ridiculous their model is before proceeding to use it for the rest of their paper.
The 1.9kg is from a 2200kCal example daily diet from 2002 (naturally from Cordain). It's not holding to the same ratios any more but the weight of plantlife is high because he sadistically includes about a pound of broccoli along with the endless salads, snacks and fruit (including a big ol' melon) in this poor girl's meal.
Yes there are some people who are eating ridiculously quantities of pointless vegetation, but it is not what most people here consider Paleo to be now and the article isn't even a sensible reflection of the literature as it was 10-15 years ago. Wikipedia in misrepresentation shock!
It seems like a lot, just because most paleo folk don't eat that much. Seems that most are too busy scarfing down a pound of meat at every meal. That or shooting coconut oil 10 times a day. Who has room for veggies when you're trying to wipe out the world's supply of bovine and coconuts?
I ate nearly 1.5 pounds of veggies yesterday, few ounces of dried fruit (equivalent of half a pound fresh?), and half a pound of meat. Not hard.
I aim to eat on average 1kg of veg a day, which would be around two large heads of broccoli. I don't think it would be difficult to hit around 1.5kg, I would just have to eat veg for breakfast, but more than just a cup of spinach with my eggs.