Which bread is best to eat for type1?
Depends on what type of insulin you are using. IF you are using humalog then you might be able to get away with certain whole grain breads, though limited quantity. Ezekiel bread is quite low glycemic, but check the carbs. Might be too slow for humalog. You'll have to figure that one out. Pretty sure you should avoid white breads.
Ciabatta -- NO! "No sugar" doesnt make a smidgen of difference if you are counting carbs, and in a non-sweet bread so little is used, it's not really the issue -- the white flour is the issue. Sugar is actually lower GI (glycemic index) than white flour (GI of 65 for table sugar, white flour is about 72-75). Although sugar is 100% carb, wheat flour is roughly 75% carb. So a teaspoon or two of sugar compared several cups of wheat flour in a bread recipe... yeah, a drop in the bucket.
Whole wheat doesnt make much of a diff either, as the fiber is non-soluble and so doesnt lower the glycemic index very much, still coming in at about 67. Most your white breads have a GI the same as the flour, 72-75. A croissant has GI of 67 (due to butter slowing things down a bit).
High quality fermented sourdough (the more sour the better) has a lower GI than other white breads, at 60, due to the bacteria action -- but is still loaded with carbs.
Chapati has a GI of about 62
100% rye bread, pumpernickel, has a GI of about 55.
100% teff bread "Injera" comes in at about 45.
Ezekiel comes in at 36
If you are using regular insulin, then you might find paleo breads more appropriate -- breads made with almond flour, coconut flour, etc. A regular insulin user might be able to get away with Ezekiel bread, if generously loaded up on the meat (to buffer), and count those carbs.
Example of paleo bread:
https://www.paleorunningmomma.com/paleo-sandwich-bread/