Aside from the reality that the paleo diet idea is pretty much complete bullshit, the other thing that gets rather ignored in that is that hunter-gatherers were a hell of a lot more active than most people are today. I know in the course of my work, during “field season” I’m outside walking between 7 to 12 miles a day, along with doing a lot of other physical things, and I end up losing quite a bit of weight.