In general terms, eating (formally, ingestion) is the process of consuming food to provide for the nutritional needs of an animal, particularly their energy requirements and to grow. All animals must eat other organisms in order to survive: carnivores eat other animals, herbivores eat plants, and omnivores consume a mixture of both; see feeding.
Manners are an important aspect of social eating in almost all human societies.
Most individuals have fairly regular meals, formally known as daily patterns of eating, and commonly most eating occurs during two to three meals per day, with snacks consisting of smaller amounts of food being consumed in between. Some nutritionists (eg BCM) however propose not to take any snacks, yet advocate the taking of 3 meals/day (of some 600 kcal per meal) with 4-6 hours recess in between . Having three well-balanced meals (thus 1/2th half of the plate with vegetables , 1/4th protein food as meat, ... and 1/4th carbohydrates as pasta, rice, ...) will then account to some 1800-2000 kcal; which is the average requirement for a regular person.
The issue of healthy eating has long been an important concern to individuals and cultures. Among other practices, fasting, dieting, and vegetarianism are all techniques employed by individuals and encouraged by societies to increase longevity and health. Some religions promote vegetarianism, considering it wrong to consume animals. Leading nutritionists believe that instead of indulging oneself in three large meals each day, it is much healthier and easier on the metabolism to eat five smaller meals each day (e.g. better digestion, easier on the lower intestine to deposit wastes; whereas larger meals are tougher on the digestive tract and may call for the use of laxatives). However, psychiatrists with Yale Medical School have found that people who suffer from Binge Eating Disorder (BED) and consume three meals per day weigh less than those who have more frequent meals. Eating can also be a way of making money (see competitive eating). Pie and sometimes cheese eating contests are one of these competitions. Sometimes people eat on picnics with family or friends.
It is an urban legend that eating fast will make you fat. Studies has disproved the theory that the body cannot keep up with the pace of the food going into the digestive tract, and thus will store the food that it cannot process as fats or energy stores. This is unscientific, as all food that enters via the mouth must pass through the entire digestive system and be broken down into simpler, usable forms that the body can make use of. However, since it takes time (up to 30 minutes) for the brain to get a signal from stomach that it is full, eating fast may cause someone to eat more thereby consuming more calories than if they ate slower, leading to weight gain.
Emotional eating is “the tendency to eat in response to negative emotions”. Empirical studies have indicated that anxiety leads to decreased food consumption in people with normal weight and increased food consumption in the obese.
Many laboratory studies showed that overweight individuals are more emotionally reactive and are more likely to overeat when distressed than people of normal weight. Furthermore, it was consistently found that obese individuals experience negative emotions more frequently and more intensively than do normal weight persons.
The naturalistic study of Lowe and Fisher compared the emotional reactivity and emotional eating of normal and overweight female college students. The study confirmed the tendency of obese individuals to overeat, but these findings applied only to snacks, not to meals. That means that obese individuals did not tend to eat more while having meals – rather, the amount of snacks they ate between meals was greater. One possible explanation that Lowe and Fisher suggest is that obese individuals often eat their meals with others and do not eat more than average due to the reduction of distress because of the presence of other people. Another possible explanation would be that obese individuals do not eat more than the others while having meals due to social desirability. Conversely, snacks are usually eaten alone.
The control of food intake is a physiologically complex, motivated behavioral system. Hormones such as cholecystokinin, bombesin, neurotensin, anorectin, calcitonin, enterostatin, and corticotropin-releasing hormone have all been shown to suppress food intake..
Physiologically, eating is generally triggered by hunger, but there are numerous physical and psychological conditions that can affect appetite and disrupt normal eating patterns. These include depression, food allergies, ingestion of certain chemicals, bulimia, anorexia nervosa, pituitary gland misfunction and other endocrine problems, and numerous other illnesses and eating disorders.