Because of instinct left over from a time when food wasn't so plentiful (Think stone age) then when food was available humans gorged as they didn't know when the next time food would be available, nowadays there is plenty food available all of the time (For most of us at least) but the instinct to gorge / over eat remains with us.
Hunger
The will to live The pain in one's stomach HUNGER
It means when you are hungry, you will eat anything. In this case, "bread" symbolizes all food. A starving person wouldn't turn down any food, just because it's old or she/he doesn't like the taste. Hunger will make you eat anything that you can swallow.
A person may not eat because they aren't hungary. They may not eat in order to lose weight. They may not eat because they don't like the food choices available. They may not eat because they feel ill. Sometimes people that want to bring awareness to a situation will go on a 'hunger strike' and refuse food to get attention for their cause.
Hunger lets you know when you need to eat. It's important because you need to eat food to stay healthy, but you don't want to eat too much. You know to eat something when you're hungry, and to stop eating when you are not hungry anymore.
because they art hunger in food whick would be yummy much
People eat because of genuine hunger, stress, boredom, depression, the food's appeal, and to be polite.
You eat
Eat
My hunger was so big i could eat a elephant
bread is used for survival because they eat it when they run out of food