Increased fat results increased leptin, which in turn keeps starvation response off. We still adapting to increased food supply. Leptin was more of value when food supplies were less and brain was to be signaled the same.
Leptin works only when there is not enough it. It turns on “starvation response” of brain.
In human history we never had enough of food. So leptin was real need to turn on brain’s “starvation response ” and in turn to switch body into saving mode. In saving mode in turns off reproduction and immune system in favour of your brain consuming your calories which were sparse in availability.
Increased fat results increased leptin, which in turn keeps starvation response off. We still adapting to increased food supply. Leptin was more of value when food supplies were less and brain was to be signaled the same.