Is it safe to skip eating all day when on no Carb or sugar?

The concern that occurs to me first is hypoglycaemia as ozempic increases insulin output. I believe it is mostly in response to food intake but I’d still monitor very closely and for now in your shoes I’d not push it past one meal a day until you can check with your dr.

I am surprised you are on this medication though. In the U.K. prediabetes is not treated with medication usually and this is not a first line medication either normally (metformin usually comes first). If you are as low carb as you describe do you really even need it as your diet will do the same thing without the side effects this (and all) medications may have?