When your fasting just to be fasting, it does zero harm to break the fast for a day. And even if you were battleing a deadly disease, it still causes no real harm, because your your own doctor, your in 100% control and you have the time and comfort of your own home to choose what you want and you KNOW you are responsible for your health and no one else on this earth can help you.
In 27 days I have eaten twice for special occasions, it is NO BIG DEAL and your body quickly removes what you ate and usually what you ate, does not taste good anyway. BAD FOOD only taste good to a polluted body, almost suggesting evil demons have made their home in the body prior to "junk food tasting good" After all, how can "good" eat something that seeks to harm the temple of God? In theory, anything that harms the body, harms your spirit. That would make the entire world a fallen race, because few people eat real foods anymore. Commercialism has poisoned all our foods and we have learned to like them, so we must wonder, WHAT is inside us that desires to harm the body? It surely is not a GOOD SPIRIT, but a spirit that wishes the body harm and premature death.
So it must be in the end of every generation, no man left on earth that can identify with God and God says "I know you not". Thus old doctors wondered what it must be like to DIE under the influence of evil drugs like Morphine? Or any unnatural death? this is why humans fear death, they do not die natural.