The reasons for feeling hungry

The main reason for weight gain is eating large amounts of food, but have you ever wondered one day about why we address those quantities?
 The main reason is the feeling of hunger outside the main meal times, so why we feel this hunger?
 1 - taking medicine makes us feel hungry.

 2 - get used to eating a meal at a certain time of the day and, of course, outside the time of the main meals. 3 - Do not sleep enough hours.

 4 - feeling thirsty or suffering from a drought degrees.

 5 - did not pass enough time after the last meal has been dealt with and therefore did not reach satiety message to the brain.

 6 - that a person is surrounded by a number of people who eat the food in front of him.

 7 - feeling bored and void.

 8 - to be the psychological state of a bad man and offset that eating shortages.

 9 - the practice of sport tired consume a lot of energy.

 10 - to smell the smell of human food smart.