The Bolton light-welterweight has enlisted the services of conditioning expert Ruben Tabares after his on-off relationship with former fitness coach Alex Ariza ended permanently recently.
Ariza - with whom Khan had split briefly before - upped and left Khan's training camp last month ahead of Saturday's WBC title scrap with Danny Garcia in Las Vegas.
Khan, left in the lurch, called in Tabares after his stellar work with his friend David Haye, the former WBA heavyweight champion.
Tabares' attention to detail was a key factor in Haye's success in jumping from cruiserweight to heavyweight glory and Khan is now seeing first-hand how impressive the conditioning coach's methods are.
"Working with Ruben has been brilliant," said Khan.
"The first thing he made me do was change my toothpaste. He's made me change to a non-fluoride toothpaste because apparently fluoride is really dangerous, contains rat poison or something and can even kill you.
"I'm one of those guys who listens to what my trainers tell me - even if it sounds a little bit strange sometimes - and I do it anyway. I do ask why, though, and that's the example he gave me. Who knows if that's the truth!
"Generally though, he's an amazing strength and conditioning coach, one of the best I've had. He's smart, clever, the way he puts me through my paces. I feel like I'm dying but it's good to be put in your discomfort zone.
"It's also good because he's worked with David Haye before and it's good when he compares me with David, saying 'David can do this,' etc, because I love a challenge and so because David did 10 reps, I'll do 20. That's the kind of guy I am."
Khan added: "It's good that he's worked with a world-class fighter before.
"He's good not only with the strength and conditioning but also with the diet part. He's got me on organic stuff, and having massages.
"He's an athlete himself, so he's not going to be telling me to have organic this, organic that but sitting eating chocolate and crisps in front of me.
"He practices what he preaches and he's eating what I eat. In a way, we live together, we eat together and we eat the same food."
Watch: Khan arrives for Garcia bout... More Videos
Khan faces WBC champion Garcia at the Mandalay Bay this weekend keen to get back in the ring after a difficult six months or so which saw him lose controversially to Lamont Peterson, only for it to emerge the American had tested positive for a banned substance.
The pair had been due to meet in a rematch in May - which was cancelled after Peterson's positive test - but Khan insists that did not hamper his preparations.
"I took a couple of weeks off when the fight was cancelled and then went back to training camp again (when the Garcia fight was made) and kind of reviewed everything and kind of got a new game plan for the fight," Khan said.
"We're going to be more than ready for this fight. We know what to do and I think maybe the fight we had lined up before was a fight that maybe is going to give us more experience and in a way help me a little bit more because it's giving me extra training and I've spent more time in the gym."