I am doing 18 hour fast each day and I have been timing myself from the moment I finish the last bite of my last meal. However I began to think that this really isn’t the start of a fast since I have food in my stomach. Also, technically, my body has source of energy for hours to come still. Does everyone mevertheless count the start of a fast as the last meal is finished?
Unless you can see inside your stomach, when you stop eating is fine. If you want to be fully digested and empty stomach for 16 hours just add some extra hours to your fast. I guess it depends what your goal is.
Fasting = Not Eating. So, the timer starts after your last bite (some might say last swallow). You can’t count the time from when the food exits the stomach. It can exit at different rates depending on the individual, amount and composition of the meal.