caroline65, although Michael Mosley drinks lots of black coffee on fasting days and Mimi Spencer has an apple mid-day, both of those things would cause me trouble, personally, from the caffeine and the carbs on an otherwise empty stomach. If I need a mid-day snack it’s got to have some protein and fat in it; a string cheese stick, a hard-boiled egg, a few nuts, a small serving of greek yogurt that I flavored myself, or peanut butter on a celery stick would work, hummus with carrot sticks might. The problem with a snack that’s mostly carbohydrate, even a healthy carbohydrate snack like an apple, is that is causes insulin to be secreted so the glucose can get into the cells, and some of us over-secrete insulin in response to mainly-carb meals or snacks.

If I feel just hungry, a not-too-brisk walk helps. I haven’t quite gotten shaky and faint, but, if I feel like I’m headed that way, lying down for half an hour or so helps. Of course that’s not going to be an option if you’re at work, so then I would go with a 100-200 calorie snack with a lot of protein and a little fat, and try to remove at least some of those calories from my evening meal. Carrying an ounce of nuts with you for emergencies is a good idea; eating just half of them might work.

I also find that I need less caffeine than usual on fasting days. This seems to be because fasting cause people to secrete more epinephrine and norepinephrine than usual.