i can tell you this much. sleep deprivation and food deprivation are really hard on your body.
together, it's a nightmare.
from experience, i have found that if you can manage to keep up with your dietary needs, sleep deprivation is a little easier and a little healthier.
i'm not saying it's easy or healthy by any means, but if you're gonna go four days without sleep, food will definately help. if you're doing drugs, eating will make the drugs feel better.
when it comes to sleep deprivation, health problems are factor, but the toll it takes on your mind is a lot more noticeable. best be careful. don't deprive yourself of sleep just for the hell of it. if you're doing stimulants, eating and sleeping makes the whole experience a lot more enjoyable.