So this weekend I had bit of time to think about Sanjis power up speculation that I mentioned on forum before.
We had Sanji going into 2 years long training that started like that:
! With Ivankov elaborating on how food forms body and how its persons environment.
As we seen Sanjis character didnt changed even after spending 2 years with Okamas but I think his body certainly did and Sanji is holding back with Life Return technique that makes him a lot more powerful fighter in CQC.
Quite long time ago we seen Lucci with his body proportions changing thanks to Rokushiki:
Not so long ago we had another Rokushiki user changing his "form" from "normal"
! to power oriented
! and we also had Lao G being matrial artist and relasing his stored muscles that he saved for many years
!
So what I think is that Sanji after eating Okamas food gotten his body changed. With eating Okamas food he might have went through change of body partially into something alike to what he hates, thus he is using form of Life Return to have his body in its normal shape same as Lucci was doing or Vergo.
We also have this page here
! with Sanji getting shivers from thinking on what would happen if fight continued. I am certain that he was not thinking that he would get beaten but rather about doing something. In volume relase he thought to himself "That was bad.. if fight would countinue like that I would've.." - or something like that. If he changes and cannot get back to normal in more than just few moments it would be extremely difficult for him to use this ability if not in near-death situation.
Using Life Return and relasing some more muscle mass/ power making him look even a bit like Okama would certainly be something really hard for Sanji to willingly use and could fit nicely with how Oda planned Sanjis training, Punk Hazard arc and now currently with making food-themed arc to be Sanjis arc-to-shine. It could all fit.