It’s a long shot, but how about oxygen deficiency? Our cells’ mitochondria use oxygen to produce ATP by ‘burning’ glucose. Could less oxygen mean less energy consumption and therefore more fat storage? All I could find about the evolution of oxygen concentration is on https://en.wikipedia.org/wiki/Oxygen#Later_history: Oxygen levels in the atmosphere are trending slightly downward globally, possibly because of fossil-fuel burning.
We’d expect altitude to be positively correlated with obesity, though.
It’s a long shot, but how about oxygen deficiency? Our cells’ mitochondria use oxygen to produce ATP by ‘burning’ glucose. Could less oxygen mean less energy consumption and therefore more fat storage? All I could find about the evolution of oxygen concentration is on https://en.wikipedia.org/wiki/Oxygen#Later_history: Oxygen levels in the atmosphere are trending slightly downward globally, possibly because of fossil-fuel burning.
We’d expect altitude to be positively correlated with obesity, though.