And back then also a lot of other factors were less than ideal. (Including lack of medication and medical science altogether.) The idea behind cold and hungry i

And back then also a lot of other factors were less than ideal. (Including lack of medication and medical science altogether.) The idea behind cold and hungry is not being that cold for that long and that hungry. Definitely not starving to death. What Sinclair hypothesizes that the reason behind the phenomena they see is that these adverse conditions trigger mechanisms in our body that are beneficial in the long term. And the very reason might be to try to make up for what causes the the lower life expectancy. Not knowing much about the topic and the mechanism, my other thought was that it tries to slow your ageing so that you can be fertile for longer in a bid to be able to reproduce when the rough times are over. So the idea is to kick in the protective mechanisms but still cause no real damage. Similarly to how you're better off eating less than what the average person does in any obese society. Even though their life expectancy is still higher than what it was 500 years ago.