I like to take a small piece or 2 of dove dark chocolate with black coffee during the fasting period—also take supplements (vit-d , statin, blood pressure medicine etc)-if I do that I can easily go between 16-20 hrs without food—- what impact doe that small pieces of dove dark chocolate have and to what extent?
If you’re taking it at the beginning or end of your fast don’t worry, if its during your 16/18 then you are breaking your fast. Depending on the size, it’ll probably cause an insulin response and kick you out of ketosis. But, if that’s what helps you get through 16 to 18 hours and your other meals during the day are not huge I’d say at a total value of your caloric target you’re ending in a deficit and it’ll result in weight-loss.
In terms of caloric intake, if it helps you reduce the volume of food you consume, you might lose weight. Probably won’t improve your health much, but you might lose weight.
It will definitely stop a period of ketosis though, so if ketosis is your goal, water is what you can have.