Researchers have found humans have a higher metabolism rate than closely related primates, which enabled humans to evolve larger brains. The study found that humans also have a higher percentage of body fat, providing the energy reserves to fuel their faster metabolism. The findings may point toward strategies for combating obesity. https://www.sciencedaily.com/releases/2016/05/160504141118.htm Paper: http://www.nature.com/nature/journal/vaop/ncurrent/full/nature17654.html
The nature paper states: "the hypothesis that the human lineage has experienced an acceleration in metabolic rate, providing energy for larger brains and faster reproduction without sacrificing maintenance and longevity." but the "Larger Brains," a fact, is pure speculation that it is due to higher metabolic rates. Higher metabolic rates are mostly due to life styles with higher power requirements. For example flying. All most all birds that fly have much higher metabolic rates than humans. I think they have confused cause and effect. Yes our larger brains do take a dispropotional amount of energy (compared to their mass) but IMHO that is why humans have higher metabolic rates than other apes. I. e. as our brains evolved with high power demands, our metabolic rate increased. I'm not sure what "faster reproduction" refers to. Many animal mate several times each day (lions, bulls, etc.) and 9 months of gestation is slow. What the hell do they speak of? Chickens can lay 300 fertilized eggs in a year!
