When do I feel hungry?

You feel hungry when your stomach is empty.

Hunger is registered in hypothalamus, a part of your brain. Many body functions including hunger and feeling full are regulated by hypothalamus. When you eat the food is digested and moves to the intestine. The stomach becomes empty again. This is the reason why you become hungry.

What is the reason for tummy rumble? To digest the food your stomach and intestines are always moving. When the stomach is empty it is filled with air. The air is pushed around in the stomach and intestines and this causes all the noises.

How to get flat stomach?

It is very easy, eat metabolism based individual diet and do few simple exercises for your stomach muscles and you could achieve this very quickly.

Weight gain is a common side effect of different medicines and if it is the case, then you have less chance. Consult your doctor to get another medicine which does not have this side effect if possible. With the help of your doctor find out the minimum but effective dose of the medicine and then it is possible to reduce some weight.