Humans hunted the megafauna to extinction, which is probably why we invented agriculture: https://theconversation.com/how-the-extinction-of-ice-age-mammals-may

Humans hunted the megafauna to extinction, which is probably why we invented agriculture: https://theconversation.com/how-the-extinction-of-ice-age-mammals-may-have-forced-us-to-invent-civilisation-128799 https://theconversation.com/how-the-extinction-of-ice-age-ma... Basically as the population grew, hunting and gathering became insufficient to feed the population. Also bone analysis shows that the health effects you mentioned happened probably BEFORE widespread adoption of agriculture, possibly due to malnutrition. This isn't far-fetched in an environment in which people are starving. And with the adoption of agriculture it got a little worse before it got better. Height and life expectancy started going up again. Basically we built better tools, we started diversifying the crops, we learned to cope with the nutritional deficiencies (for example we started eating dairy) and we eventually adapted, like we always do.