Anthony Joshua's trainer Robert McCracken wants the heavyweight champion to be leaner for his next bout following what looked a sluggish win over Carlos Takam in October.
'AJ' is preparing to announce a spring contest with Joseph Parker this week as the pair prepare to unify four versions of the top division titles.
In the Takam clash, Joshua won during the tenth round after scaling 254 pounds, despite the Cameroonian coming in a very late notice for the Cardiff battle.
For his imminent 21st outing, McCracken is hoping Joshua can drop down around half a stone (seven pounds) in order to maximise speed against dangerous and unbeaten New Zealander Parker.
"The emphasis is on being as quick as possible and taking as little punishment, (and weighing) a bit lighter would allow him to do that," McCracken told BBC Radio 5 Live.
"He's a bit lighter (than that) at the minute, he's probably eased off a bit on the conditioning side of things strength wise.
"We do 12 weeks for his fights so I can give him some days off during the camp here and there as we go. He's done four weeks with me in London before Christmas - boxing and cardio - so he's in good shape, sharper and a little bit leaner than he was of late," he added.
Parker is due to follow promoter David Higgins to London later this week as the finalization of a deal draws near, with the challenger taking up to 33% of the pot for a career-high purse of around £7 million ($9.5m).
Cardiff's Principality Stadium is set to host Joshua once again, with up to 75,000 people cramming into the venue for a fight to be broadcast on Sky Sports Box Office and Showtime.