Andy Ruiz's sparring partner has revealed just when and how the Mexican fighter put on so much weight ahead of his rematch with Anthony Joshua.
Ruiz lost his four belts at the first time of asking after being schooled by AJ, who got revenge for the outcome of their first bout in New York and beat 'the Destroyer' on points to reclaim his titles.
Incredibly, the Mexican weighed in at a stone heavier than he did the first match and admitted he was "partying too much' and "ate everything" ahead of the second match.
He lost a great deal of mobility going into the clash in Saudi Arabia and it clearly showed as Ruiz produced a polar opposite performance to the one that saw him shock the world in June.
Michael Hunter sparred with Ruiz to help him prepare for his first world title defence and believes he completely lost his focus when he jetted across to Saudi for the latter stages of his camp, hence the detrimental weight increase.
"I really think he lost [track of] the weight when he was over in Saudi," the 31-year old told Behind the Gloves.
"We're over there two/three weeks before for preparation and our routine ends up changing from that camp.
"When you're heavyweights and you don't have weight to watch, it's very easy to overeat.
"I think that's what happened to him when he went over there, I think most of the undisciplined things started at the end of his camp."
Initial images had led many to believe Ruiz had actually lost weight to begin with but it proved not to be the case on the scales.
And Hunter, 18-1, in the squared circle, is in no doubt that his weight ballooning was the key factor in his defeat.
"For anybody to gain 15/20lbs in two weeks - because he was not that big," he added.
"Once you gain that much weight that fast, it's definitely gonna show out in your shape."
Ruiz Jr has been the subject of widespread criticism for his lack preparation, including his own father, who says he lost his drive because of the fame that arrived after his shock win in June.
In the most brutal assessment of his display, Frank Warren, Tyson Fury's promoter, called Ruiz "a disgrace to the belts" and said he "ate himself out of contention" - before writing, "King of the heavyweight division to Burger King in the space of six months," as his final line in his column on the fight.
- Fans stunned by Andy Ruiz Jr's incredible body transformation, he now has a six-pack
- Andy Ruiz Jr Reveals Exactly How Much Weight He Has Lost Ahead Of Anthony Joshua Rematch
- Eddie Hearn Responds To Andy Ruiz Jr's Weight Loss, Claims He's Tricked Fans
- It Appears Anthony Joshua Has Found His Sparring Partner Ahead Of Andy Ruiz Jr Fight