'Family By the Ton' Star Who Weighed 845 Pounds Excited About New Sex Life

"Family by the Ton" star Casey King has shed HUNDREDS of pounds since his time on the series ... and his dating life and sex life have dramatically improved.

Casey tells TMZ ... being with women has been a new experience, saying that wasn't a part of his life back when he was at his heaviest at 845 pounds. He didn't lose his virginity until his mid-30s.

With the lbs coming off, Casey says he's gotten more confident in the bedroom ... using a potato metaphor --- watch the video, you'll understand.

The reality star is gung ho on getting his excess skin removed sometime this year ... he's meeting with doctors for a pretty radical procedure. A GoFundMe for his surgery has produced results ... he says $18k is already sitting in his bank account.

Fans of the show remember Casey got gastric bypass surgery, which reduced his weight to 525 lbs. Now, how's this for progress? He now tips the scales at 232 pounds! From his heaviest, Casey's dropped an astonishing 613 lbs!!!