And (the people of the Cave [Kahf]) stayed in their cave for three hundred years and they added another (nine) years (to that). Surah Kahf (18:25)
Here the incident of the people of cave (Ashab-e-Kahf) is being mentioned. These are those pious servants of Allah Most High who were asleep for 309 years. During this entire period, their bodies did not change at all. This whole period, they neither ate nor drank anything. Eating/drinking are the basic needs of the human body. No one can remain without this need being fulfilled. Let alone decades and decades, no one can remain even a few days without eating/drinking, but these pious servants of Allah Most High spent a period of 309 years without doing so.
This is the miracle through the power of Allah Most High that the People of the Cave spent a period as long as 309 years without eating/drinking. Their bodies were not affected at all and even the dog, which remained at their doorstep, was safe.