'Biggest Loser' Host Bob Harper on the Mend after Heart Attack

Bob Harper is on the mend, which is great, but the picture shows the seriousness of his recent health crisis.

TMZ broke the story ... "The Biggest Loser" host suffered a major heart attack 2 weeks ago that left him unconscious for 2 days. He spent 8 days in the hospital and is now resting in NYC ... doctors won't let him fly home to L.A. just yet. We don't know when the pic was taken. Bob tells us he's out now.

Bob just posted, "I'm on the mend now & want to thank everyone for the outpouring of messages and support."

The 51-year-old says there's a history of heart disease in his family.

Get well soon.