Eve: How the Female Body Drove 200 Million Years of Human Evolution

by Cat Bohannon

In the mid-1990s, a group of orthopedists ran a study comparing small samples of their patients’ skeletal muscles. They found that a certain metabolic pathway (the “mitochondrial electron transport complex III”) was significantly more active in their younger women subjects than in the young men.[*11] This particular pathway has to do with using fat to give muscle cells energy. Young women’s bodies are really, really good at lipid beta-oxidation: using our mitochondria to take little molecules of fat and break them down. And while all mitochondria are able to do this, having muscles that are especially good at it may be built into our female body plan. A more recent study showed that genes related to this particular sort of fat metabolism are more expressed in young women’s muscle cells than in men’s.