Eggs, for many T1s, require almost as much insulin as carbohydrate. Yet eggs contain no noticeable carbs. What they do have is loads of protein and fats, and considering that eggs are food sources for chicks to grow up, probably very easily assimilable access to amino acids.
When we eat eggs, we see blood glucose levels rise in a relatively short period, yet there’s no discernible reason for this if we look at traditional methods of accounting for carb raises.
What we know about eggs is that they are one of the foods with a high relative Leucine and Arginine content.
L-Arginine and L-Glutamine (also present in relatively high proportion in eggs) also induce Glucagon secretion (more information available here).
In addition, Egg Yolks contain as their most prevalent fatty acids, Oleic and Palmitic Acid, which account for 70% of the fatty acids in those yolks. If you follow the link in the last paragraph, you’ll also find that Oleic and Palmitic acid are the fatty acids that most induce glucagon secretion.
We also know that cellular uptake of amino acids requires insulin, so to avoid a low blood glucose level when protein is ingested, the body normally produces glucagon to induce the liver to release glucose to counter this risk. Obviously in a T1D, with no onboard insulin, this shows as an increase in blood glucose levels.
So here we have an answer as to why eggs cause a blood glucose spike without any carbs. And why many other things do as well.