Coffee itself increases blood glucose and many type 1 diabetics need to inject insulin for this.
But if they were just having the milk in that quantity, no.
I thought it was more about the milk having calories and strictly you shouldnt have cals in the fasting window. Black coffee alone has almost zero cals Im a dirty faster lol and have drop of skimmed milk in tea and coffee and it works for me.
U can experiment and see how it affects you.
I am very fond of my morning tea with ginger and milk - around 30 ml semi skimmed. I didnt give it up for the longest time But when weight didnt budge at all, experimented with black coffee. Instant loss and it is continuing. Even that 18 calories made a big difference for me š«I m doing 16:8 and 5 2 diet. Normal healthy diet.
I wonāt be able to answer your question but I can tell you about my experience with switching to black coffee. Iāve always had cream and sweetener with mine and forced myself to switch to all black coffee. After a couple of years of the bitterness and Iām still not completely enjoying it, but it gets the job done.
However, now I reward myself occasionally with a premium coffee place, not Starbucks, and that black cup of coffee is amazing. And for even a better reward I may add some cream and sweetener for a great experience.
To try to answer your question from what Iāve read over time is the range is from zero to 50 calories wonāt break your fast. It depends on what youāre reading from.
Id focus on learning to get tough on yourself and go black. If you really ācantā do it id suggest doing a small amount of grass fed butter (salted or unsalted) and or mct oil. The pure fat wont spike your insulin as much as the milk sugars will found in milk and cream
I hated black coffee until I switched to using a french press and grinding the beans every morning. I also tried a bunch of different coffee beans from different regions and at different roasting levels until I found out that I donāt really like ācoffeeā in general, which is why I always had to add sugar and cream, but I LOVE Ethiopian light roast coffee, so Iām happy to drink it black.