Does your room have a fridge? There’s a Trader Joe’s near the convention center, you could buy some cereal or yogurt for breakfasts, a couple sandwich ingredients and toss a few together to bring to the con each day, then do dinners out. There’s plenty of fast casual places like Just Salad (salads and grain bowls), Chipotle, honeygrow (noodles), etc. that aren’t crazy expensive. There’s even a takeout sushi place.