Put lots of lettuce and tomatoes on. I love the beans and rice. Sometimes the same food is served in about three different qualities. The waitress usually can tell you how. A tostada with a lot of lettuce may be light, or a small burrito.
Tortilla soup is good too.
That's the best way we've found to not over indulge. Stay away from the buffets. Then only eat half and take the rest home. Microwaved - it isn't bad. Sometimes folks select the tostada salad which can be deceiving since the shell is deep fried and large and there's often cheese, olives and sour cream with it.