Whenever I read critiques of paleo/primal it's always the misconceptions that are front and center. Ever notice how they always say something like..."sure fruits and veggies are good for you and yeah you lose weight, but........" What follows is meat and fat bashing in some form or another with little understanding about portion control, organic vs CAFO, lean meats in the case of paleo and so on. The biggest lie of all is the whole unsustainable claim. What they are really admitting to without even realizing it is how addicted they are to bread-grain products and cannot imagine giving them up. That has nothing to do with sustaining; it is strictly a lack of will. Also a lack of understanding that once you do kick them, you really don't crave them too much anymore. I admit I still get some cravings, but I don't give in and it doesn't really bother me. I have no problem sustaining a primal diet nor I think would anyone else who commits to doing it right.