The definition of 'breaking a fast' is complex and may depend on whether one is considering a rise in blood glucose or downstream molecular signals, and the context of recent physical activity.

“when we're talking about breaking a fast are we talking about a rise in blood glucose or are there molecular signals Downstream of of a rise in blood glucose that um cannot be reversed in other words if I'm gonna eat my first meal every day at noon and I'm gonna eat my last bite of food at 8 00 pm and at 9 00 a.m for whatever reason I have coffee with one teaspoon of sugar in it I suppose in the strictest sense I've broken my fast but maybe by if I went for a hard run that morning maybe by 9 30 a.m I'm back in a quote unquote fasted state so what is the fasted State really”