Fainting was some next level bs but it was required for plot. I.e. Hiyori/ getting inside that hut in Ringo.
The amount of days that's passed in Wano before he passed out I believe is 8 days
(in total if I'm not mistaken he hasn't eaten for 7-8 days)
In chapter 7 :
Zoro: Whew, I'm stuffed...!!!
I guess nine days without eating is about the farthest you can go!!
In chapter 685 :
Luffy :Wow, you must be really Hungry too.
Momonosuke : Nonesense … Huff… A Warrior Does not Feel Hunger after just… huff … Ten days of fasting huff huff…
Luffy : TEN DAYS?!
*Simply speaking Momo is exhausted* - later flies out of a garbage suite but loses consciousness after that and is carried by Luffy.
This is also the Onomatopoeia which Oda uses to convey hunger is : ぐぎゅる
Here are some panels :
I don't have a panel for Otama but it is chapter 914 she has the same : ぐぎゅる