D.K.
First and foremost, I would NEVER give a child 4 bowls of mac & cheese! Do you have ANY idea how many carbohydrates are in that? How about filling her up with FRUITS AND VEGETABLES that contain FIBER that will fill her up. On top of that, what about BALANCE in her diet? Where is the protein? How FAST does she eat? SLOW HER DOWN! If she eats fast, you HAVE to slow her down. The brain cannot/does not have adequate amount of time to tell you that you are full. Protein is needed to slow down insulin release. It keeps you fuller longer.
Set a time limit and if you have to spend 10-15 minutes eating one bowl of something, then so be it. It CAN be taught.
In addition, IS she adequately hydrated? MANY TIMES, dehydration can be mistaken as hunger. WATER, MILK and limited juice- 100% juice (NOT juice blends) NOT soda.
These ALL need to be taken into consideration. You didn't mention whether what her weight is like.