Thanks to bixy and crinkly for a lot of straight dope surrounding ancestral diets. My impression has been humans have eaten cooked, processed starches for a long time and I’m not about to stop doing so.
Amy, obesity is such a complex issue. I don’t think it’s only attributable to modern foods although nutrient deficiency probably plays a role. I also think it’s multi-generational. I.e. after a couple generations of socio-environmental stressors, inadequate nutrition, and dieting mentality people will be a lot more prone to obesity.