The Brit has revamped his camp after being upset by the Mexican in June in search of flipping the result on Saturday.
And he maintains discarding heavy weight lifting and remaining in the boxing gym will give him a better chance at recapturing the world heavyweight titles.
“Imagine this, the clue is before I would spend more time when not preparing for a fight doing cardio and strength and conditioning,” Joshua told 5 Live with Costello and Bunce. “This time I spent all the time in the boxing gym.
“Before I was trying to squat 200kg and bench press a house because I used what got me to where I needed to get to, which was brute strength and physicality, but then I realised there is a sweet science to this sport.
“At my last weight I came in at like 116kg (255.7 pounds/18.25 stone), 115kg (253.5 pounds/18.1 stone), that’s with doing weights. I’m going to say we knock off about 5kg or so, because I’ve focused on boxing and the diet.
“Maybe even lighter (than 17 stone/238 pounds), maybe even lighter, I’m punching like a horse kicking back. We say loose and heavy.”
Joshua also revealed how he has been sparring since he arrived in Saudi Arabia, including a late session this week.
“Yes, there’s been intense sparring, I sparred yesterday I done my last six rounds, I invested in bringing out five sparring partners,” Joshua revealed.
“Sparring at the British embassy was good because it was outdoors. It was outdoors to acclimatise to the weather which was smart.”
Register for free to continue reading
Registration is a free and easy way to support our truly independent journalism
By registering, you will also enjoy limited access to Premium articles, exclusive newsletters, commenting, and virtual events with our leading journalists
Already have an account? sign in
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies