Seeking clarity on the term "it breaks a fast"

Thanks, but ketosis and fasting aren't really the same thing. I mean, people intermittent fast, religious fast from sunrise to sunset, etc, so they aren't going into ketosis. I guess what I was getting at is how big of an impact on the benefits of fasting does a break cause? Say for example a person has been water fasting for 5 days, and drinks a cup of instant coffee not knowing it contains some hidden carbs or sweeteners. Are they now knocked out of fasting and how long before the regain the same state they were in before the ill-fated cup of coffee? Is it days, like re-entering ketosis, or merely hours until the coffee is digested and processed?

/r/fasting Thread Parent