Earlier quoted context omitted.
I wonder if there's a relationship to the obesity epidemic, especially since it's not just humans that are getting larger but also lab animals, pets, and wild animals living close to humans [1]. What if we're compelled to eat more calories when we're not getting enough nutrients in our diets? This would impact any animals consuming lower quality fruits and vegetables. [1] https://www.nature.com/articles/news.2010.628
It seems highly plausible to me that that's part of the story. Another part of the story is that modern food is designed to be super-tasty: http://www.paulgraham.com/addiction.html
I wonder how long that lasted