Why do Sanji and Smoker still need nicotine when not in their own bodies? During the Punk Hazard arc, Trafalgar Law swaps Sanji into Nami's body and Smoker into Tashigi's. In spite of them being in bodies not addicted to nicotine, it seems they both still need to smoke. Nami (in Franky's body) even offers Sanji a pack of cigarettes saying something to the effect, &quot;You need them, right?&quot;
When Trafalgar Law swaps everyone, the image shown is some weird heart thing, not swapping their brains. I assume this is some kind of representation of a soul, but if they still need nicotine, maybe I'm wrong. So, what exactly does Law swap? And why do Sanji and Smoker still need to smoke?
If you ask any smoker, he will tell you that most of the addiction comes from the brain as it gives the neuro-signals for pleasure when smoking. Most smokers can't quit not because the body demands nicotine, but because of the apparent relaxating effect that is produced by smoking and the habbit that results from it.
Smoking is a recreational drug in public view and tends to work as such.
Edit: And now on how Law's power work. The swap technique that Law uses looks like he is swaping the &quot;hearts&quot; of people, but because they retain their original thoughts, memories and even habbits (like smoking) makes me believe that it's actually their consciousness that is being transfered since all these reside in the brain and not the heart.
Hope this answers your question.