I live about 35 miles north of Houston. I was able to go the last few years and carpooled with my husband that worked downtown. I had to get there around 7 AM. My plan has been to stay in the convention center.
On the second floor above the show floor is a cafe that serves breakfas. It's pricey, but what I expected at a convention center. Down the way is a kiosk that serves bagels, muffins, and coffee. There is also a Starbucks at the end of the 2nd floor (I think it's on the second floor).
For meals and breaks during the show there is a large cafeteria type area with many different "restaurants". They are stations - most of the food is prepared outside of the building. The food is good not great and I can easily spend $10 - $15 for a meal. But I was greatful I wasn't spending a lot of time going to get lunch - I had more time for the show.
There are other food stations on the second floor. I also had lunch in the connecting hotel at a Mexican food restaurant that was good but even more expensive.
I hope you have a great time.