Unfortunately, IIIT Delhi's mess food is like any other typical mess food. I have friends in other IITs and I heard from them that their mess food is better. The mess scenes are very chaotic, especially during the day.
There are frequent menu changes but only for the show. No new dishes are added and only the order or serving is changed. They even interchange lunch and dinner and claim this act as updating the menu. The mess app doesn't improve the food quality.
The food served is of substandard quality and the majority of students tend to order their food online. So, be prepared to be disappointed by the IIITD Mess.