Jillian Michaels Speaks Out, Torches 'Biggest Loser' Documentary and NBC Series

Jillian Michaels says Netflix’s "Biggest Loser" documentary isn't just full of lies -- it’s part of a long history of the franchise trying to take her down ... and she's giving TMZ all the receipts to prove it.

TMZ caught up with Jillian hot off her IG blast and lawsuit threat Tuesday, and she doubled down -- telling us the documentary paints a false picture, starting with Dr. Robert Huizenga claiming he never worked with her -- something she says is BS 'cause she's got hundreds of emails proving otherwise.

Listen to the full interview ... Jillian blasts the way the documentary twisted her role on the show, accusing Dr. H of dangerously yanking contestants off their meds cold turkey -- while she was the one stepping in to protect them.

As for the caffeine bombshell ... Jillian insists it was never banned, says the show flip-flopped about it constantly, and flat-out denies ever training S14 contestant Rachel Frederickson -- despite the documentary suggesting she secretly slipped her pills.

But the wildest part -- Jillian tells us back in the day she got a call from Maria Menounos, who told her NBC sources claimed she gave contestants an illegal substance that sent someone to the hospital. Jillian says she never gave any illegal substances to anyone ... Maria investigated, and a top NBC exec confirmed it was false.

Still, Jillian claims then-NBC exec Brandon Riegg -- the same guy who produced this Netflix doc -- was involved in the mess ... and she believes this is proof the powers-that-be have had it out for her all along.

Jillian makes it clear to us again -- she and her team are still deciding whether to unload all their receipts or let powerhouse attorney Bryan Freedman take Netflix, Bob Harper, Dr. Huizenga and the doc’s producers to court.

There’s plenty more -- from her longstanding bad blood with fellow trainer Harper, to why she skipped the doc altogether, to her claim Netflix ignored her lawyers' fact-check requests. Jillian says she doesn’t want to spend the time and money ... but the documentary is so damning, she may have no choice.