I'm with Zetz. The only good thing I can say about any of that is that you should find out what works for YOU. "Paleo" is a bullshit term with no meaning other than ridiculously fluid and arbitrary limitations. The article you sent, just like pretty much all "paleo" literature, is based on pure speculation and talking around the point.
Do "we" really know that grains aren't good to eat? Some of the only studies actually done on varying levels of grain consumption have shown a positive correlation between increased whole grain intake and improved cardiovascular indicators. Recent archaeological evidence (ignored by Cordain, or else he's unaware of it) has indicated that humans may have been eating grain for more than 100,000 years. And as Cordain allows, the concentrated and systematic cultivation of grain is what enabled the rise of civilization and eventually the computers and internet you and I are using to interact. Without grain-based agriculture, we would still be hunter-gatherers. We can debate whether that's a good thing or not on balance, but we should probably first strip to our leather underpants and return to the African savannah from whence we came. Furthermore, there is evidence that the advent of agriculture actually caused an acceleration in human evolution. People who live in areas with historically greater grain consumption show greater numbers of alleles adapted to help us process grain. The idea that we're genetically the same as our distant ancestors is wrong.
Cordain talks about everything in black and white: Either you are EATING ALL GRAINS ALL THE TIME AND SHUTTING OFF HEALTHY FOODS or you are PALEO AND VIRTUOUS IN LINE WITH OUR EVOLUTIONARY HISTORY AS DEFINED BY LOREN CORDAIN. Garbage. It's entirely possible to include whole grains as part of a perfectly healthy, balanced diet. Same goes for the satanic HFCS. If all you eat is bread, then yeah, you're in trouble. But that would either indicate stupidity on your part or an utter lack of options. For example, see the plight of starving people in India or sub-Saharan Africa.
If you have Celiac disease, then by all means, stay away from gluten. If you do well on a low-carb diet, by all means, stick with it. But I'll stick with my toast, pasta, and occasional cookie or milk shake, thank you very much. I also eat lean meat, fatty meat, greens, fruit, dairy, eggs, nuts, etc.
If you want Aragon's fully-realized take on "paleo," I'm happy to send you the issue of AARR from a year ago in which the feature article is "An Objective Look at the Paleo Diet." PM me your email address if you're interested.
