Many low carbers have done this and I am certainly one of them. I think it's fine to do for a short period of time but certainly not ideal fro anything longer than that. All 1 food plans tend to be pretty wrong and are really just crash-type diets IMO. I don't think they fit into the paleo paradigm very well. But for quick weight loss or something like that I don't have a problem with because darn it they really seem to work short term anyway (I think most struggle to keep any weight lose off unless you are solidly footed in a healthy eating plan which most who attempt this are not.)

I have actually gone as long as 2 months eating only eggs. I'd give anything not to have to admit to that but there you have it. Since then I've done a few 1 week or 3-4 days stints. I find it works best for me to eat 2 eggs every couple of hours so maybe 10-12 in a day. I wouldn't say I felt my best eating only eggs but I didn't feel sick or have any issues related to it.

In my experience, eggs do not keep me full for too long. That said, my egg fast of 5 days were utterly miserable.

However, my experience does not correlate with many others. I guess it works for some people since it generally does keep one satiated for a good while and thus leads to an unintended calorie restriction just like most low carb plans. In addition, the food reward pathway most likely diminishes after so many eggs...

give it a shot... but becareful with the over consumption of eggs, as one can develop an allergy to them.

In January 2010 I ate nothing but eggs for 1 week.

I averaged about 12 eggs a day, usually 4 at a time, 3 times a day. But some days I wasn't hungry enough to eat the full dozen. Other days I was really hungry and ate more of them. It was actually a pretty inexpensive way to eat! I had some of them fried (in a very small bit of butter), some scrambled, and some hard boiled.

I did have some black coffee in the morning but didn't drink anything else but water. I lost 5 pounds during that week and I felt great the entire time. Definitely a crash diet type of thing. But I really didn't enjoy not being able to eat anything else...though I felt great physically and had lots of energy, I just got very sick of eggs!

You'll find out pretty quickly if you're intolerant. I tried to eat 8 hard boiled eggs a day for a while (on top of the rest of my diet) and would get severe stomach aches. Turns out I can't eat egg whites (at least if they're boiled). Hard-boiled yolks are fine though. Now I just toss the whites.

Apparently egg white intolerance is a lot more common than egg yolk intolerance, but there's something like 7 potentially problematic proteins between them, and 212 degrees F isn't enough to denature them completely.

Additionally, you're only talking about doing this for a few days, but if someone did this for longer, they'd likely become deficient in niacin and vitamin C, though they'd get at least some of everything else.

There's really little point in calling a diet of only eggs a "fast". Protein is one of the main things to abstain from during a fast - small amounts of slow release carbs or fat are sometimes permitted, depending on the goals - but to my knowledge, the longevity/disease prevention benefits of fasting relate to autophagy. All an "egg fast" is is a ketogenic crash diet.