That doesn’t explain why both eating or skipping breakfast affect masking. Everyday, everyone either eats breakfast or they don’t, they can’t both be abnormal.

They could be if your options are “skip breakfast or eat something insane for breakfast because your brain and body crave it and it’s all you can manage to get yourself to eat if you are gong to eat.”

Think about how you might react if you were talking with someone about what they had for breakfast today and they answered “a bag of cotton candy and a beer”. That’s really weird right? Like you might be concerned about them for making that choice right? And what if on other days you notice that they’re a bit grumpier or more tired and they admit to not eating breakfast on those days. Now imagine over a few months you come to realize that your co-worker is either always skipping breakfast despite how it affects them, or they’re eating a bag of cotton candy and a beer. You’d probably be really concerned for them. You might even in an attempt to be helpful and supportive try and help them have better breakfasts, maybe even bring in some bagels (even though they always decline). This is an extreme example of course but for some autistic people, they will go through phases were if they eat they can only eat very specific things and those things aren’t going to be “normal”. During that time, the decision to eat or not to eat and the decision for what to eat are extremely fraught things because very well meaning and well intentioned people find the decisions being made odd and feel like they need to “help”. But if you don’t want the help (or worse if you know you should be doing something different but your mind will make you physically ill if you do) all that “help” is really just another stressor on top of everything else.