2 Things - I'm not sure how much it matters what we ate 20,000 years ago. For example, lactose tolerance is assumed to have developed very recently in most pla

2 Things - I'm not sure how much it matters what we ate 20,000 years ago. For example, lactose tolerance is assumed to have developed very recently in most places. People are opportunistic omnivores and it would make sense for them to be able to adapt quickly (several generations) to new eating habits. - Guessing what people ate is tricky. If all we have to go on is modern evidence, we have a huge level of disparity. Also, just because (for example) New Guineans were primarily hunter gatherers in modern times doesn't automatically mean they were similar in every other way to pre historic Europeans.