Eating is individual activity; unless you are infant, individual grabs foodstuff and bring it to his mouth.
Being hungry is feeling the physiological need to eat. Having appetite is desiring the act of eating (also used figuratively). Other reasons for starting a meal at a particular time are habit, agreement with others, or not having an oppportunity later on.
Eating can be very emotional. Some people having trouble with eating are called eating disorder.
Lack of available food can cause famine or starvation. Some people intentionally take no food for certain period of time mostly for religous reasons.
See also food, potluck, restaurant.