L.A. Sheriff Launching Inquiry into 'Biggest Loser' Doping Allegations

Updated at 2 p.m. May, 31, 2016

CALABASAS, CA - The Los Angeles county Sheriff's Department is launching an inquiry into the alleged illegal use of narcotics on the NBC show, "The Biggest Loser," authorities said Tuesday.

The long-running NBC show about diet and exercise has been under fire since a New York Post story about trainers on the show giving contestants illicit drugs so they'd lose weight.

The show's producers denied the allegations, saying the safety and well-being of contestants are "paramount."

"Contestants are told at the start of the show that there is zero tolerance for any weight loss drugs. We prohibit the use of any illegal substances, in addition to the many other rules and procedures of the show that are designed to ensure safety," the show producers said in a statement to Patch.

An unnamed source told the Post one of the show trainers, Bob Harper and one of his assistants, supplied a contestant with Adderal and ephedra extract pills known as "yellow jackets." Ephedra was banned by the Federal Drug Administration in 2004.

"Based on the information contained in the news report, Malibu/Lost Hills Station personnel are conducting an inquiry regarding the unsubstantiated allegations," the sheriff's department said in a news release.

Much of "The Biggest Loser" is filmed at King Gillette Ranch in unincorporated Calabasas.

Earlier this year, a study by the journal Obesity reported that the extreme weight loss contestants experienced on the show caused irreversible changes to their metabolisms. Contestants would have to eat a lot fewer calories than their non-dieting counterparts to maintain their weight, which is why many have gained all the weight they've lost back.

—Photo credit: Trae Patton/NBCUniversal