The problem with the paleo theory of obesity is that it doesn't match the facts very well. Obesity has been an issue for the past 50 years, not 10,000. I prefer the technology explanation for modern obesity. Like, "Smart people at frito-lay have scoured the earth for ingredients and chemical processes to make hyper-palatable and inexpensive foods like nacho cheese Doritos. Humans are not evolved to eat these foods in reasonable portions." The industrialization of food production aligns with the facts of obesity much better.

That being said, a "paleo" diet is a great way to lose weight and maintain a strong and healthy body. It is just not a very good explanation for modern obesity.