I was not able to find a recipe without any fat, sugar or eggs. Here is a recipe with minimal amounts:

2 oz. fresh yeast
1/2 cup oil
9 cups flour
1/2 cup sugar
2 tsp. sugar
3 cups water
2 tsp. salt

Dissolve yeast and 2 tsp. sugar in 1/2 cup warm water. Sift flour into a very large bowl. Make a well in middle of flour. Add 2 1/2 cups water, oil, 1/2 cup sugar, salt, and yeast mixture. Mix until a soft dough is formed. Knead for about 10 minutes on a lightly floured surface. Place dough in a greased bowl. Cover with a towel. Let dough rest until double in bulk. Punch down. Divide into 9 balls. Let dough rest 10 minutes. Roll into ropes and braid into 3 loaves. Let rise 20-30 minutes until doubled in size. Bake at 350 degrees F for 45 minutes to 1 hour. Makes 3 challahs.


Bobbie commented:
One of your readers had asked for a challah recipe without fat, eggs or sugar. My German father-in-law taught me his "bashis" - German water challah. It has no fat at all, almost no sugar, and no eggs in the challah, just one for glazing, which can be eliminated. It is a heavy challah and very crusty. It's not for everyone, but my family (and a lot of my friends) love it:

OPA’S BASHIS
4 pkg dry yeast or 1½ large pkg fresh
1½ cups warm water
Mix the yeast into the warm water. Add a little (1 tsp?) sugar and let sit for 5 minutes.

5 lbs bread flour (plus extra)
3 tblsp salt
1 tblsp sugar
Mix all into very large bowl. Pour the yeast mixture plus 4 more cups warm water. Knead. Let rise 1 hour. Shape into loaves. Brush on egg. Sprinkle on poppy seed.

Bake at 400 degrees (do not preheat oven) for 1 hour.

Note: The second rising wasn't left out my mistake. I don't let the challot rise after the shaping. I put them into a cold oven and immediately turn on the heat. Any rising will happen as the oven heats up. They are not supposed to be soft fluffy challot. These are German bashis! (It is pronounced ba {as in back} shiss) I am typing with a smile - my father-in-law was very German. Like I said before, they are not for everyone. However, most people love them. Interestingly, they are more suitable halachically for hamotzi than many other challot since there is no juice, eggs or even oil in them.