Last last year, Jason Mayden—global design director for Nike’s Jordan brand—was prepping his children for bed with an homage to the famous Chicago Bulls chant (“What time is it? Jammy time!”) when his 10-year-old son’s forlorn expression grabbed his attention.

“My son got out of the shower. He was getting dressed, staring at himself in the mirror. I looked at his face, and I saw a face of defeat,” Mayden says. “I asked him why . . . he said, ‘I don’t love who I am.'”

Mayden realized he’d never grasped the psychological effect that obesity could have on a child. And he felt a sudden sense of urgency. He left Nike, he says, because it was “the natural choice that any father would make,” to devote himself to finding the cause for his son’s rapid weight gain. He wanted to understand why, though he’d thought his family was living a healthy lifestyle, his son was having difficulty breathing and sleeping. He studied nutrition, genetics, GMO food products, and the way families were eating. The culprit Mayden points to today, diagnosed after visiting several doctors, was his son’s collection of food allergies and intolerances.

Read the full Fast Company article here.