In fact, cancer incidence and all cause mortality increase the further you are from the equator. Brown fat activation is not efficient from an energy perspecti

In fact, cancer incidence and all cause mortality increase the further you are from the equator. Brown fat activation is not efficient from an energy perspective. If you live somewhere cold, with generally sparse food supply, burning precious calories to warm yourself up isn’t a winning strategy. I highly doubt brown fat activation is more prevalent in the colder climate populations.