饭 (traditional 飯) = 饣 (the food radical, a shrunken 食 'to eat') + 反 (for the sound). The food radical marks dozens of eating words; here it's cooked rice, and by extension, a meal.
饭 is cooked rice — and because rice is THE staple, 饭 means 'a meal' in general: 吃饭 (to eat / have a meal — with 吃), 早饭 (breakfast), 做饭 (to cook — with 做). The classic Chinese greeting isn't 'how are you?' but 你吃饭了吗? ('Have you eaten?') — a warm way of showing care that dates back to leaner times. 米饭 specifically is steamed white rice. To share 饭 is to share life.
The food radical (饣) — cooked rice, a MEAL.
你吃饭了吗? ('Have you eaten?') is a classic Chinese greeting — caring about your meal is caring about you, a habit from leaner times. 吃饭 covers any meal, not just rice.