Agni is the root of all reasons to uphold the body. In Ayurveda Agni is a very vast word. Loss of appetite, indigestion, no interest in food are separate concepts.  Agni in our digestive system is just like the native fire place to cook food. If you feed no fuel, then the fire will be extinguished- no food during hunger, gradually appetite will go down. Heavy fuel in the fire place will extinguish the fire due to no space for Oxygen- heavy food (qualitatively/ quantitatively/ frequently) will ruin down the appetite and digestion power. Water, even hot water will bring the fire to zero. Likewise intake of liquid in empty stomach during hunger will diminish the fire of digestive system. Everybody is requested to take care.

How much food one should take? Half stomach is the answer. Another  one fourth of the stomach is filled with water while the last one fourth is left vacant for air movement and peristaltic movement. Water should not be taken immediately before or after food. It may be taken in between the fooding. Water intake just before food will reduce health while after food will help gaining weight.