'Avoid overeating'. It's a common piece of advice we all hear. But how do you know when you are full? When do you stop? Well your body has a very fine-tuned system in place and it does not only entail the working of your stomach. Wondering how you can read its signals? Here's how your body tells you you're full. The feedback mechanism Did you know that it takes 20 minutes for your brain to respond to signals from your stomach that it is full? One of the most basic mechanisms it uses is when your stomach expands due to