Know When to Stop

Lately my heartburn is coming back. I know that I will always have problem around my stomach (somehow), but still sometimes I have difficulty to figure out what exactly is the cause of my stomach problem (in this case today is the heartburn).
I got this heartburn since I started my work here. That was almost 3 years ago. What has been changed is definitely my meal. I have German lunch every day now, instead of having my own meal (self made, which is more Asian style). 
At first I didn't think that it mattered, but I was wrong. When you change your eating habit, increase or decrease your meal, sometimes you'll just get some adjustment in your body (I mean, some more fat or less fat here and there :) ). But sometimes it is also possible that your body just refuses the change. For my case, it's like it cannot stand anymore. Producing more acid which press my throat and vomiting the food. Strange though, seems like our body can really set its own limit. 
And here starts the thing. Sometimes you can be really hungry, like you can eat everything.  So do I. Sometimes I want to eat more in one go. But the body cannot stand. Somehow I should try to understand my body. My mind should be able to say stop and take no more food. In the end it's really how to control your mind and know when to stop.