Eating

{{Short description|Ingestion of food}} {{Redirect-several|Eating|Eat|Feeding}} {{pp-semi-indef}} [[File:Amandines de Provence, poster by Leonetto Cappiello, 1900.jpg|thumb|288px|Amandines de Provence, poster by Leonetto Cappiello, 1900, which shows a woman eating almond cookies]]

'''Eating''' (also known as '''feeding''' or '''consuming''') is the ingestion of solid food for digestion. In biology, this is typically done to provide heterotrophic organisms with the essential nutrients and energy needed for metabolism and physical growth, since they are incapable of acquiring nutrition and energy intrinsically like autotrophs and therefore must ingest external organic matters in order to survive. Animals, in particular, have evolved different forms of eating — carnivores and scavengers eat flesh (meat) from other animals, herbivores and algivores eat plants and algae, omnivores consume a mixture of both plant and animal matters, and detritivores and coprophages eat detritus and feces. Animals and phagotrophs eat and digest food internally, as opposed to decomposers such as fungi and microbes, who secrete enzymes to digest organic matters externally before absorbing the nutrients and thus do not "eat" food.

For humans, eating is more complex, but is typically an activity of daily living. Human eating is usually organized into routine sessions known as meals, where proper courses of cooked food are consumed, typically with a decent quantity of staples; and more time-flexible casual eatings known as snacks, where small quantities of typically non-staple food (often convenience food, sometimes raw foods such as fruits and nuts) are consumed more for the purpose of degustation than to satiate hunger. Formal sessions of eating, e.g. in a gathering or a date, are known as '''dining''', and large dining events where many people are invited to eat food together are known as banquets or feasts. The craft of preparing and presenting meals for formal eating is called culinary arts, and the person performing such tasks is known as a cook, chef or cater depending on the respective nature of food service.

Physicians and dieticians consider eating a healthy diet essential for maintaining peak physical condition. Some individuals may reduce their amount of dietary intake, which may be a result of a voluntary choice as part of dieting lifestyle or as fasting for reasons of religious food prohibition, abstinence or political protest (i.e. a hunger strike). Limited consumption or rationing may also be due to logistical reasons such as a food shortage or a famine, in which case it will lead to starvation and undernutrition. On the contrary, overeating and excessive intake of calories (overnutrition) may lead to obesity and associated health problems, and while the reasons behind it are myriad, its prevalence in the developed world has led some public health professionals to declare an "obesity epidemic".

==Eating practices among humans== {{Unreliable sources|date=April 2019}} Many homes have a large kitchen area devoted to preparation of meals and food, and may have a dining room, dining hall, or another designated area for eating.

Most societies also have restaurants, food courts, and food vendors so that people may eat when away from home, when lacking time to prepare food, or as a social occasion.<ref name="I42HC">John Raulston Saul (1995), "The Doubter's Companion", 155</ref> At their highest level of sophistication, these places become "theatrical spectacles of global cosmopolitanism and myth."<ref name="IxPKc">David Grazian (2008), "On the Make: The Hustle of Urban Nightlife", 32</ref> At picnics, potlucks, and food festivals, eating is the primary purpose of a social gathering. At many social events, food and beverages are made available to attendees.

People usually have two or three meals a day.<ref>{{cite journal |last1=Lhuissier |first1=Anne |last2=Tichit |first2=Christine |last3=Caillavet |first3=France |last4=Cardon |first4=Philippe |last5=Masulo |first5=Ana |last6=Martin-Fernandez |first6=Judith |last7=Parizot |first7=Isabelle |last8=Chauvin |first8=Pierre |title=Who Still Eats Three Meals a Day? Findings from a Quantitative Survey in the Paris Area. |journal=Appetite |date=December 2012 |volume=63 |pages=59–69 |doi=10.1016/j.appet.2012.12.012 |pmid=23274963 |s2cid=205609995 |url=https://www.researchgate.net/publication/234011608 |access-date=19 September 2020}}</ref> Snacks of smaller amounts may be consumed between meals. Doctors in the UK recommend three meals a day (with between 400 and 600 kcal per meal),<ref name="smart">{{cite web|title=Be calorie smart 400-600-600|url=http://www.nhs.uk/Change4Life/Pages/calories.aspx|publisher=nhs.uk|access-date=25 May 2017|archive-date=26 May 2017|archive-url=https://web.archive.org/web/20170526130528/http://www.nhs.uk/change4life/pages/calories.aspx|url-status=live}}</ref><ref name="XZar9">{{cite web|title=Cut down on your calories|url=http://www.nhs.uk/Livewell/Goodfood/Pages/eat-less.aspx#you|date=15 October 2015|publisher=nhs.uk|access-date=25 May 2017|archive-date=4 June 2017|archive-url=https://web.archive.org/web/20170604093057/http://www.nhs.uk/Livewell/Goodfood/Pages/eat-less.aspx#you|url-status=live}}</ref> with four to six hours between.<ref name="7rCUD">{{cite news|last1=Sen|first1=Debarati|title=How often should you eat?|url=http://timesofindia.indiatimes.com/life-style/health-fitness/diet/How-often-should-you-eat/articleshow/15616282.cms|access-date=25 May 2017|work=The Times of India|date=27 July 2016|archive-date=30 May 2017|archive-url=https://web.archive.org/web/20170530061221/http://timesofindia.indiatimes.com/life-style/health-fitness/diet/How-often-should-you-eat/articleshow/15616282.cms|url-status=live}}</ref> Having three well-balanced meals (described as: half of the plate with vegetables, 1/4 protein food as meat, [...] and 1/4 carbohydrates as pasta, rice)<ref name="Un12y">{{Cite web|url=https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/vegetables-and-fruits/|title=Vegetables and Fruits|date=Sep 18, 2012|website=The Nutrition Source|access-date=March 7, 2021|archive-date=March 7, 2021|archive-url=https://web.archive.org/web/20210307202459/https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/vegetables-and-fruits/|url-status=live}}</ref> will then amount to some 1800–2000 kcal, which is the average requirement for a regular person.<ref name="Nj11Q">{{Cite web|url=http://www.iloveindia.com/nutrition/food-facts/calorie-requirement-of-body.html|title=Daily Calorie Requirements of An Adult Male, Female|website=www.iloveindia.com|access-date=2008-06-03|archive-date=2017-07-13|archive-url=https://web.archive.org/web/20170713055300/http://www.iloveindia.com/nutrition/food-facts/calorie-requirement-of-body.html|url-status=live}}</ref>

In jurisdictions under Sharia law, eating may be proscribed for Muslim adults during the daylight hours of Ramadan.<ref name="uSEqw">Sharia and Social Engineering: p 143, R. Michael Feener - 2013</ref><ref name="XF41j">FOOD & EATING IN MEDIEVAL EUROPE - Page 73, Joel T. Rosenthal - 1998</ref><ref name="l0Y2Y">Conscious Eating: Second Edition - Page 9, Gabriel Cousens, M.D. - 2009</ref>

<gallery widths="200" heights="180"> File:Abell-photoblog28.jpg|Eating with a fork at a restaurant File:Hayat-02.JPG|Traditional way of eating in Uzbekistan File:Girl with chopsticks at dumpling restaurant.jpg|Chinese girl eating with chopsticks File:Ethiopian food.jpg|Ethiopians eating with hands File:Photo degustation.JPG|English women eating biscuits File:Japanese Gothic lolita.jpg|Japanese girl eating a piece of cake File:Preparing The Feast.jpg|Balinese preparing food for eating </gallery>

==Development in humans== Newborn humans are not developed enough yet to chew and thus cannot handle eating solids, and survive solely on drinking liquid breast milk or infant formula.<ref name="ZYeJj">{{cite web|title=How to combine breast and bottle feeding|url=http://www.nhs.uk/Conditions/pregnancy-and-baby/Pages/combining-breast-and-bottle.aspx|publisher=nhs.uk|access-date=5 October 2017|archive-date=28 September 2017|archive-url=https://web.archive.org/web/20170928184552/http://www.nhs.uk/conditions/pregnancy-and-baby/pages/combining-breast-and-bottle.aspx|url-status=live}}</ref> As infant development proceeds, small amounts of puréed baby foods are sometimes fed to babies as young as two or three months old, but most infants do not eat anything solid until they are between six and eight months old. Premastication, in which adults chew up food and then "kiss-feed" a softened food bolus into the infant's mouth, can also be seen in many undeveloped countries as a form of improvised puréed food. The practices of feeding only liquid or semi-liquid food to young infants is because they still have few teeth and an immature digestive system.

Between 8 and 12 months of age, the digestive system improves and deciduous teeth progressively emerge (i.e. "teething"), and many babies can begin weaning and eating finger foods. Their diet is still limited, however, because most babies lack molars or canines at this age, and often have a limited number of incisors. By 18 months, babies often have enough teeth and a sufficiently mature digestive system to eat the same foods as adults. Learning to eat food is a messy process for children, and they often do not master neatness or eating etiquette until five or six years old.<ref>{{Cite web |last=Insight |first=Food |date=2021-10-27 |title=Infant and Toddler Feeding from Birth to 23 Months: Making Every Bite Count |url=https://foodinsight.org/starting-solids-a-resource-for-parents-and-their-infants/ |access-date=2024-05-11 |website=Food Insight |language=en-US }}{{Dead link|date=July 2025 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

===Eating positions=== Eating positions vary according to the different regions of the world, as culture influences the way people eat their meals. For example, most of the Middle Eastern countries, eating while sitting on the floor is most common, and it is believed to be healthier than eating while sitting at a table.<ref name="DQJmV">{{Cite book|title=The Middle Eastern American Experience|last=Donovan|first=Sandy|publisher=Twenty-First Century Books|year=2010|isbn=9780761363613|location=United States|pages=68}}</ref><ref name="0nFM2">{{Cite journal|last1=Brito|first1=Leonardo Barbosa Barreto de|last2=Ricardo|first2=Djalma Rabelo|last3=Araújo|first3=Denise Sardinha Mendes Soares de|last4=Ramos|first4=Plínio Santos|last5=Myers|first5=Jonathan|last6=Araújo|first6=Claudio Gil Soares de|date=2012-12-13|title=Ability to sit and rise from the floor as a predictor of all-cause mortality|url=http://cpr.sagepub.com/content/early/2012/12/10/2047487312471759|archive-url=https://web.archive.org/web/20130112022009/http://cpr.sagepub.com/content/early/2012/12/10/2047487312471759|url-status=dead|archive-date=2013-01-12|journal=European Journal of Preventive Cardiology|language=en|pages=892–898|doi=10.1177/2047487312471759|issn=2047-4873|pmid=23242910|volume=21|issue=7|s2cid=9652533}}</ref>

Eating in a reclining position was favored by the Ancient Greeks at a celebration they called a symposium, and this custom was adopted by the Ancient Romans.<ref name="themet">{{cite web |title=The Roman Banquet |url=https://www.metmuseum.org/toah/hd/banq/hd_banq.htm |website=The Met |publisher=Metropolitan Museum of Art |access-date=2019-04-13 |archive-date=2019-04-13 |archive-url=https://web.archive.org/web/20190413204054/https://www.metmuseum.org/toah/hd/banq/hd_banq.htm |url-status=live }}</ref> Ancient Hebrews also adopted this posture for traditional celebrations of Passover.<ref name="avp">{{cite web |title=Reclining |url=http://avirtualpassover.com/reclining.htm |website=A Virtual Passover |access-date=2019-04-13 |archive-date=2019-10-23 |archive-url=https://web.archive.org/web/20191023192849/http://avirtualpassover.com/reclining.htm |url-status=live }}</ref>

===Compulsive overeating=== {{Main|Compulsive overeating}}

Compulsive overeating, or emotional eating, is "the tendency to eat in response to negative emotions".<ref name="uynvS">{{cite journal | last1 = Eldredge | first1 = K. L. | last2 = Agras | first2 = W. S. | year = 1994 | title = Weight and Shape Overconcern and Emotional Eating in Binge Eating Disorder | doi = 10.1002/(SICI)1098-108X(199601)19:1<73::AID-EAT9>3.0.CO;2-T | journal = International Journal of Eating Disorders | volume = 19 | issue = 1| pages = 73–82| pmid = 8640205 }}</ref> Empirical studies have indicated that anxiety leads to decreased food consumption in people with normal weight and increased food consumption in the obese.<ref name="b4SNJ">{{cite journal | last1 = McKenna | first1 = R. J. | year = 1972 | title = Some Effects of Anxiety Level and Food Cues on the Eating Behavior of Obese and Normal Subjects: A Comparison of Schachterian and Psychosomatic Conceptions | journal = Journal of Personality and Social Psychology | volume = 22 | issue = 3| pages = 311–319 | doi=10.1037/h0032925| pmid = 5047384 }}</ref>

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.<ref name="Lowe">{{cite journal | last1 = Lowe | first1 = M. R. | last2 = Fisher | first2 = E. B. Jr | year = 1983 | title = Emotional Reactivity, Emotional Eating, and Obesity: A Naturalistic Study | journal = Journal of Behavioral Medicine | volume = 6 | issue = 2| pages = 135–149 | doi=10.1007/bf00845377| pmid = 6620370 | s2cid = 9682166 }}</ref>

The naturalistic study by 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 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.<ref name="Lowe" />

===Hunger and satiety=== {{Further|Hunger (motivational state)}}

There are many physiological mechanisms that control starting and stopping a meal. The control of food intake is a physiologically complex, motivated behavioral system. Hormones such as cholecystokinin, bombesin, neurotensin, anorectin, calcitonin, enterostatin, leptin and corticotropin-releasing hormone have all been shown to suppress food intake.<ref name="QvWqA">Geiselman, P.J. (1996). Control of food intake. A physiologically complex, motivated behavioral system. Endocrinol Metab Clin North Am. 1996 Dec;25(4):815-29.</ref><ref name="pBHak">{{cite web |title=omim |url=https://www.ncbi.nlm.nih.gov/omim/?term=164160&rn=1 |access-date=20 June 2019 |archive-date=8 March 2021 |archive-url=https://web.archive.org/web/20210308203406/https://www.ncbi.nlm.nih.gov/omim/?term=164160&rn=1 |url-status=live }}</ref>

Eating rapidly leads to obesity and overeating, probably because the feelings of satiety can be slower.<ref name="pmid29440054">{{cite journal | vauthors = Hurst Y, Fukuda H | title=Effects of changes in eating speed on obesity in patients with diabetes: a secondary analysis of longitudinal health check-up data | journal= BMJ Open | volume=8 | issue=1 |at=Article no. e019589 | year=2018 | doi= 10.1136/bmjopen-2017-019589 | doi-access= free| pmc=5855475 | pmid=29440054}}</ref>

====Initiation==== thumb|German Shepherd puppy eating out of a human hand

There are numerous signals given off that initiate hunger. There are environmental signals, signals from the gastrointestinal system, and metabolic signals that trigger hunger. The environmental signals come from the body's senses. The feeling of hunger could be triggered by the smell and thought of food, the sight of a plate, or hearing someone talk about food.<ref name="Carlson">{{cite book|last=Carlson|first=Neil|title=Physiology of Behavior|year=2010|publisher=Allyn & Bacon|location=Boston, MA|pages=412–426}}</ref> The signals from the stomach are initiated by the release of the peptide hormone ghrelin. Ghrelin is a hormone that increases appetite by signaling to the brain that a person is hungry.<ref name="Ghrelin">{{cite web|last=Funai, M.D.|first=Edmund|title=Ghrelin, Hormone That Stimulates Appetite, Found to Be Higher in PWS|url=http://www.pwsausa.org/research/ghrelin.htm|access-date=29 April 2012|url-status=dead|archive-url=https://web.archive.org/web/20120531141800/http://www.pwsausa.org/research/ghrelin.htm|archive-date=31 May 2012}}</ref>

Environmental signals and ghrelin are not the only signals that initiate hunger, there are other metabolic signals as well. As time passes between meals, the body starts to take nutrients from long-term reservoirs.<ref name="Carlson" /> When the glucose levels of cells drop (glucoprivation), the body starts to produce the feeling of hunger. The body also stimulates eating by detecting a drop in cellular lipid levels (lipoprivation).<ref name="Carlson" /> Both the brain and the liver monitor the levels of metabolic fuels. The brain checks for glucoprivation on its side of the blood–brain barrier (since glucose is its fuel), while the liver monitors the rest of the body for both lipoprivation and glucoprivation.<ref name="NCBI">{{cite web|last=Berg|first=JM|title=Section 30.2Each Organ Has a Unique Metabolic Profile|url=https://www.ncbi.nlm.nih.gov/books/NBK22436/|work=Biochemistry 5th Edition|publisher=W H Freeman|access-date=29 April 2012|archive-date=13 December 2014|archive-url=https://web.archive.org/web/20141213035629/http://www.ncbi.nlm.nih.gov/books/NBK22436/|url-status=dead}}</ref>

====Termination==== There are short-term signals of satiety that arise from the head, the stomach, the intestines, and the liver. The long-term signals of satiety come from adipose tissue.<ref name="Carlson" /> The taste and odor of food can contribute to short-term satiety, allowing the body to learn when to stop eating. The stomach contains receptors to allow the body to know when it is full. The intestines also contain receptors that send satiety signals to the brain. The hormone cholecystokinin is secreted by the duodenum, and it controls the rate at which the stomach is emptied.<ref name="CCK">{{cite journal|last=Little|first=TJ|title=Role of cholecystokinin in appetite control and body weight regulation.|journal=Obesity Reviews|author2=Horowitz, M |author3=Feinle-Bisset, C.|year=2005|pmid=16246215|doi=10.1111/j.1467-789X.2005.00212.x|volume=6|issue=4|pages=297–306|s2cid=32196674}}</ref> This hormone is thought to be a satiety signal to the brain. Peptide YY 3-36 is a hormone released by the small intestine and it is also used as a satiety signal to the brain.<ref name="Peptide YY 3-36">{{cite journal|last=Degen|first=L|title=Effect of peptide YY3-36 on food intake in humans.|pmid=16285944|doi=10.1053/j.gastro.2005.09.001|volume=129|journal=Gastroenterology|year=2005|issue=5|pages=1430–6|doi-access=free}}</ref> Insulin also serves as a satiety signal to the brain. The brain detects insulin in the blood, which indicates that nutrients are being absorbed by cells and a person is getting full. Long-term satiety comes from the fat stored in adipose tissue. Adipose tissue secretes the hormone leptin, and leptin suppresses appetite. Long-term satiety signals from adipose tissue regulates short-term satiety signals.<ref name="Carlson" />

Cessation of eating within two hours of sleeping can reduce body weight.<ref name="pmid29440054" />

====Role of the brain==== The brain stem can control food intake, because it contains neural circuits that detect hunger and satiety signals from other parts of the body.<ref name="Carlson" /> The brain stem's involvement of food intake has been researched using rats. Rats that have had the motor neurons in the brain stem disconnected from the neural circuits of the cerebral hemispheres (decerebration), are unable to approach and eat food.<ref name="Carlson" /> Instead, they must obtain their food in a liquid form. This research shows that the brain stem does in fact play a role in eating.

There are two peptides in the hypothalamus that produce hunger, melanin concentrating hormone (MCH) and orexin. MCH plays a bigger role in producing hunger. In mice, MCH stimulates feeding and a mutation causing the overproduction of MCH led to overeating and obesity.<ref name="MCH">{{cite web|last=Shimada|first=M|title=MCH (Melanin Concentrating Hormone) and MCH-2 Receptor|url=http://www.phoenixbiotech.net/allobesity/Catalog%20Files/MCH%20Section/MCH.html|work=Mice lacking Melanin-Concentrating Hormone are hypophagic and lean.|access-date=29 April 2012|url-status=dead|archive-url=https://web.archive.org/web/20090905145154/http://www.phoenixbiotech.net/allobesity/Catalog%20Files/MCH%20Section/MCH.html|archive-date=5 September 2009}}</ref> Orexin plays a greater role in controlling the relationship between eating and sleeping. Other peptides in the hypothalamus that induce eating are neuropeptide Y (NPY) and agouti-related protein (AGRP).<ref name="Carlson" />

Satiety in the hypothalamus is stimulated by leptin. Leptin targets the receptors on the arcuate nucleus and suppresses the secretion of MCH and orexin. The arcuate nucleus also contains two more peptides that suppress hunger. The first one is cocaine- and amphetamine-regulated transcript (CART), the second is α-MSH (α-melanocyte-stimulating hormone).<ref name="Carlson" />

==Disorders== {{main|Eating disorder}}

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 malfunction and other endocrine problems, and numerous other illnesses and eating disorders. A chronic lack of nutritious food can cause various illnesses, and will eventually lead to starvation.

While changes in appetite can result from various physical and psychological conditions, including depression, allergies, and anxiety; anorexia and bulimia are specific eating disorders that profoundly impact the entire body.<ref>Baenas, I., Etxandi, M., & Fernández-Aranda, F. (2023). Medical complications in anorexia and bulimia nervosa. Complicaciones médicas en anorexia y bulimia nerviosa. Medicina clinica, S0025-7753(23)00478-5. Advance online publication. https://doi.org/10.1016/j.medcli.2023.07.028</ref> In anorexia nervosa, people restrict their calorie intake out of fear of gaining weight. This malnutrition leads to an unhealthy weight, significantly impacting overall health.<ref>Robatto, A. P., Magalhães Cunha, C., & Moreira, L. A. C. (2023). Diagnosis and treatment of eating disorders in children and adolescents. Jornal de pediatria, S0021-7557(23)00155-9. Advance online publication. https://doi.org/10.1016/j.jped.2023.12.001</ref> Bulimia is characterized by recurrent episodes of binge eating, involving the consumption of a substantial amount of food within a short period. Subsequently, individuals engage in maladaptive behaviors, such as inducing vomiting, excessive physical activity, and using laxatives as compensatory measures.<ref>Yu, Z., & Muehleman, V. (2023). Eating Disorders and Metabolic Diseases. International journal of environmental research and public health, 20(3), 2446. https://doi.org/10.3390/ijerph20032446</ref>

If eating and drinking is not possible, as is often the case when recovering from surgery, alternatives are enteral<ref name="Feeding">{{cite web|title=Pediatric Feeding Tube|url=https://pediatricfeeding.com/tube-feeding/|publisher=Feeding Clinic of Santa Monica|access-date=8 July 2013|archive-url=https://web.archive.org/web/20160302145614/https://pediatricfeeding.com/tube-feeding/|archive-date=2 March 2016|url-status=dead}}</ref> nutrition and parenteral nutrition.<ref name="8iG4f">Heisler, Jennifer. "Surgery." About.com. N.p., May–June 2010. Web. 13 Mar. 2013.</ref>

==Other animals== ===Birds=== {{Excerpt|Bird|Diet and feeding}}

===Mammals=== {{Excerpt|Mammal|Feeding}}

==See also== {{Portal|left=yes|Food|Eating}} {{Div col|colwidth=22em}} * Aphagia * Chewing * Competitive eating * Crop * Dietary supplement * Dieting * Dining in, formal military ceremony * Drinking * Energy crop * Fine dining * Foodways * Forced feeding * Muk-bang * Restaurants * Swallowing {{Div col end}}

==References== {{Reflist}}

==External links== {{Wiktionary}} {{Wikiquote}} {{Commons category}} * [http://ec.europa.eu/health-eu/my_lifestyle/nutrition/index_en.htm Health-EU Portal – Nutrition]

Category:Eating behaviors Category:Dining Category:Food and drink Category:Nutrition Category:Physiology