> I assume this has never happened in human history at this scale.
We never had synthetic nitrogen fertilizers before. This is the first era where humanity does not have to experience widespread, frequent, deadly, hunger. This is also why there are eight billion people on the planet: we have enough calories to support that many. There were only 1.7 billion people when the Haber process was invented.
Although true, it still has nothing to do with the obesity rate. My comment was about the idea that it was a lack of food availability that prevented obesity before about 1980.
We never had synthetic nitrogen fertilizers before. This is the first era where humanity does not have to experience widespread, frequent, deadly, hunger. This is also why there are eight billion people on the planet: we have enough calories to support that many. There were only 1.7 billion people when the Haber process was invented.