That's the million dollar question! I mean, I don't know. I think it varies for each person.
I read The Obesity Code by Jason Fung and pretty much believed in what he said, but I felt so lousy when I didn't eat in the morning that I started to question it. I do think that in terms of evolution, we're not well-adapted to our current late-capitalist eating culture, and should probably be hungry more often.
There are some studies showing that early time restricted feeding (intermittent fasting, but with an early breakfast and an early dinner) helps (see https://nutritionandmetabolism.biomedcentral.com/articles/10.1186/s12986-021-00613-9, table: https://nutritionandmetabolism.biomedcentral.com/articles/10.1186/s12986-021-00613-9/tables/3 and also look up Satchin Panda (apparently he has a new book. I don't know how good it is, but it might be worth a look: https://www.amazon.com/Circadian-Diabetes-Code-Discover-Prediabetes-ebook/dp/B08Y8DZ8YQ/). Certainly many people do lower their A1C through fasting, but not everyone. I did alternate day dieting (800 calories 3x/week) which did lower my A1C, but I think it had more to do with just being at a caloric deficit.
Another theory that intrigues me is the idea of the Personal Fat Threshold (https://optimisingnutrition.com/ted-naimans-dam-fat-storage-insulinographic-explained/). The idea is that people will start to see diabetes symptoms when their body fat gets too high for their ability to handle it, and that can be pretty low for some people.