From thyroid cancer to 40‑hour fasts: Inside Daymond John’s obsession with biohacking and living longer

Daymond John has amassed an estimated $350 million fortune, invested in dozens of companies on Shark Tank, written five best-selling books, and helmed his own fashion brand, FUBU, by hustling harder than the next person. 

But these days, John is just as focused on outliving his competition as out-negotiating them. After a thyroid cancer diagnosis in 2017, he has turned himself into a biohacker—stacking 40-hour fasts, red-light bed therapy, cold plunges, and hyperbaric oxygen sessions...