“Adolescence is one of the big time periods of growth, next to infants,” said Taiya Bach, a member of the teaching faculty at the University of Wisconsin-Madison’s Department of Nutritional Sciences told Gizmodo. “They need way more calories than a grown adult does.”
“Even if you are overweight, you still have that growth piece because a bunch of your calories are still going towards hormones and development and bone growth,” Bach said.