Cutting sleep for productivity was bad idea [Video]

Daniel Lubetzky says his days of choosing work over sleep are long gone, and he’s more productive because of it.

Lubetzky, the billionaire Kind Snacks founder and newest permanent investor judge on ABC’s “Shark Tank,” was once a major night owl — perhaps involuntarily, he says. He couldn’t relax without clearing his inbox, leading to countless all-nighters: While his family was sound asleep, he responded to messages.

“I have a little bit of an obsessive personality,” Lubetzky, 56, tells CNBC Make It. “If I had emails in my inbox [waiting to be] read, I couldn’t take it. I was enslaved by my inbox. So after my kids and wife went to bed at 10 or 11 at night, I would start checking all my emails. Sometimes, I finished at 2, 3, 4 a.m.”

His work ethic helped Kind double its annual sales for more than 10 years in a row, he told Inc.in …