Chawal ka bhav is an Urdu saying which means "effect of rice". It could also be interpreted as the "benefits of rice".
However, in modern times this phrase is used in a broader sense to signify how food affects one's mood. For example, if someone says their stomach hurts because they ate too much spicy food, that person would say that the stomach ache was caused by their chawal ka bhav.
This saying stems from when Indians believed that foods changed one's emotions and moods.