(Newser) – San Francisco police officer Mark Yesitis has seen some bad stuff: "I've seen people's brains outside their heads," he tells the New York Post. What could be worse than that? "Being on The Biggest Loser." Yesitis is among several contestants of NBC's long-running weight-loss program to tell the newspaper that the show asked them to take stimulants, lie about how much they ate, and generally participate in unsafe weight loss practices. In particular, the newspaper says trainer Bob Harper and an assistant "supplied contestants with Adderall and 'yellow jackets'—pills that contain ephedra extract." The FDA banned ephedra in 2004, the newspaper adds. "Nothing can be further from the truth," the show's Dr. Rob Huizenga counters, adding that the show has "zero tolerance for any weight-loss drugs." The alleged misconduct, he says, is "in direct conflict with my lifelong devotion to health and fitness."