I'm Daymond John from 'Shark Tank.' Here's a day in my life as I biohack for longevity, fast intermittently, and squeeze in any nap I can get.

Daymond John. The Shark Group This as-told-to essay is based on a conversation with Daymond John, the 57-year-old CEO of FUBU based in Miami. It's been edited for length and clarity. I started my entrepreneurial journey handing out flyers in my neighborhood of Hollis, Queens, for $2 an hour. In grade school, I scraped the paint off pencils and customized them with the customer's name for a fee. I waited tables at Red Lobster in the early 1990s, around the time I told my mother I wanted to st...