I also had this. It could seriously put down 5-6 slices of pizza for example and go back to get more even when I was full to the point of being sick. Its like my stomache and brain did not communicate. If I got hungry and was delayed/denied food I became the biggest B to ever walk the earth! It turns out that the celiac was causing some vitamin deficiancies. The jury is still out on the blood sugar issues but since cutting gluten and supplementing for my deficiancies, I am so much better. I only eat 2 slices of gluten free pizza and Im satisfied.
I sympathise absolutely - previously I have almost made myself sick by eating so much but I really had no idea at all that I was full! I ate a chicken burger and then straight after felt still hungry so I started eating a sandwich and half way through felt like I was going to be sick, it took me a bit of time to realise it was because I was so full but my brain wasn't 'sensing' it at all!