Pregnancy places a lot of extra strain on the body, requiring more food than usual over the course of nine months to support the pregnancy and the growing baby. It turns out that estimates range widely — from about 50,000 to nearly 85,000 extra calories over the course of an entire pregnancy. Those are additional calories on top of what that person would need if they weren't pregnant.
Sign up for the Live Science daily newsletter nowGet the world’s most fascinating discoveries delivered straight to your inbox. "Fundamentally, energy expenditure is all about all of your cells doing their jobs all day," Pontzer said."In pregnancy — when the body grows something around 12 kilos in a normal pregnancy — all that extra tissue all extra cells that weren't there before. And they've all got to do their jobs."