I've tried it before. By the night of the third day I was already faint. I probably would have completed if it wasn't for my then partner saying they wanted me to stick around. If you have the conviction, it's really not as difficult as you might think. Not for me anyway. But I've also rowed a marathon and was technically diagnosed with an eating disorder so my experience may not be representative of standard expectation. I've also gone a week without food before. You really don't feel hungry at all after the first two days or so. Thirst is another matter but it's really just the dryness and your mouth feeling gross.
The most important thing to note is that it is incredibly important to not have anything whatsoever. A sip of water, one bite of food, can make the entire experience unbelievable miserable. The ideal scenario seems to be that you become weak, feel faint, and eventually just pass out and don't recover. If you eat or drink anything, even a little, you prolong the process by a significant margin. Because your body is in such a deficit for a longer period of time you'll start experiencing other negative symptoms related to your skin. The 7 days I went without food was awful at the end. My skin was extremely sensitive, stretch marks, peeling, I was emaciated. I believe it was because I was still lightly hydrated. The 3 days I went ingesting nothing at all left me FAR weaker than the 7 days I went with little.
In short, if you can't commit, or if anyone intervenes, you are not going to have a good time. But if you can commit, and you really have to be completely certain since it's so easy to stop, you cannot have anything at all.
This is just based on my own experience for whatever it's worth.
p.s Don't forget to take bodyweight into consideration.