Editing Carbohydrate (section)

==Nutrition==
[[File:GrainProducts.jpg|thumb|upright|[[cereal|Grain]] products: rich sources of carbohydrates]]

Carbohydrate consumed in food yields 3.87 kilocalories of energy per [[gram]] for simple sugars,<ref>{{cite web|url=http://ndb.nal.usda.gov/ndb/foods/show/6202|title=Show Foods|work=usda.gov|access-date=June 4, 2014|archive-date=October 3, 2017|archive-url=https://web.archive.org/web/20171003224558/https://ndb.nal.usda.gov/ndb/foods/show/6202|url-status=dead}}</ref> and 3.57 to 4.12 kilocalories per gram for complex carbohydrate in most other foods.<ref>{{cite web|url=http://www.fao.org/docrep/006/y5022e/y5022e04.htm|title=Calculation of the Energy Content of Foods – Energy Conversion Factors|work=fao.org|access-date=August 2, 2013|archive-date=May 24, 2010|archive-url=https://web.archive.org/web/20100524003622/http://www.fao.org/DOCREP/006/Y5022E/y5022e04.htm|url-status=live}}</ref> Relatively high levels of carbohydrate are associated with processed foods or refined foods made from plants, including sweets, cookies and candy, table sugar, honey, soft drinks, breads and crackers, jams and fruit products, pastas and breakfast cereals. Refined carbohydrates from processed foods such as white bread or rice, soft drinks, and desserts are readily digestible, and many are known to have a high glycemic index, which reflects a rapid assimilation of glucose.  By contrast, the digestion of whole, unprocessed, fiber-rich foods such as beans, peas, and whole grains produces a slower and steadier release of glucose and energy into the body.<ref>{{cite web |url=https://www.diabetes.org.uk/upload/How%20we%20help/catalogue/carb-reference-list-0511.pdf |title=Carbohydrate reference list |website=www.diabetes.org.uk |access-date=October 30, 2016 |archive-date=March 14, 2016 |archive-url=https://web.archive.org/web/20160314193016/https://www.diabetes.org.uk/upload/how%20we%20help/catalogue/carb-reference-list-0511.pdf |url-status=dead }}</ref>  Animal-based foods generally have the lowest carbohydrate levels, although milk does contain a high proportion of [[lactose]].

Organisms typically cannot metabolize all types of carbohydrate to yield energy. Glucose is a nearly universal and accessible source of energy. Many organisms also have the ability to metabolize other [[monosaccharide]]s and [[disaccharide]]s but glucose is often metabolized first. In ''[[Escherichia coli]]'', for example, the [[lac operon]] will express enzymes for the digestion of lactose when it is present, but if both lactose and glucose are present, the ''lac'' operon is repressed, resulting in the glucose being used first (see: [[Diauxie]]). [[Polysaccharide]]s are also common sources of energy. Many organisms can easily break down starches into glucose; most organisms, however, cannot metabolize [[cellulose]] or other polysaccharides such as [[chitin]] and [[arabinoxylans]]. These carbohydrate types can be metabolized by some bacteria and protists. [[Ruminant]]s and [[termite]]s, for example, use microorganisms to process cellulose, fermenting it to caloric short-chain fatty acids. Even though humans lack the enzymes to digest fiber, dietary fiber represents an important dietary element for humans.  Fibers promote healthy digestion, help regulate postprandial glucose and insulin levels, reduce cholesterol levels, and promote satiety.<ref>{{cite journal | vauthors = Pichon L, Huneau JF, Fromentin G, Tomé D | title = A high-protein, high-fat, carbohydrate-free diet reduces energy intake, hepatic lipogenesis, and adiposity in rats | journal = The Journal of Nutrition | volume = 136 | issue = 5 | pages = 1256–1260 | date = May 2006 | pmid = 16614413 | doi = 10.1093/jn/136.5.1256 | doi-access = free }}</ref>

The [[Institute of Medicine]] recommends that American and Canadian adults get between 45 and 65% of [[food energy|dietary energy]] from whole-grain carbohydrates.<ref>Food and Nutrition Board (2002/2005). ''[https://archive.today/20070210182833/http://newton.nap.edu/books/0309085373/html Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein and Amino Acids]''. Washington, D.C.: The [[National Academies Press]]. Page [http://newton.nap.edu/books/0309085373/html/769.html 769] {{Webarchive|url=https://web.archive.org/web/20060912060636/http://newton.nap.edu/books/0309085373/html/769.html |date=September 12, 2006 }}. {{ISBN|0-309-08537-3}}.</ref> The [[Food and Agriculture Organization]] and [[World Health Organization]] jointly recommend that national dietary guidelines set a goal of 55–75% of total energy from carbohydrates, but only 10% directly from sugars (their term for simple carbohydrates).<ref>Joint WHO/FAO expert consultation (2003). ''[https://web.archive.org/web/20110423051140/http://www.who.int/hpr/NPH/docs/who_fao_expert_report.pdf]'' ([[Portable Document Format|PDF]]). Geneva: [[World Health Organization]]. pp. 55–56. {{ISBN|92-4-120916-X}}.</ref>  A 2017 [[The Cochrane Database of Systematic Reviews|Cochrane Systematic Review]] concluded that there was insufficient evidence to support the claim that whole grain diets can affect cardiovascular disease.<ref name="pmid28836672">{{cite journal | vauthors = Kelly SA, Hartley L, Loveman E, Colquitt JL, Jones HM, Al-Khudairy L, Clar C, Germanò R, Lunn HR, Frost G, Rees K | display-authors = 6 | title = Whole grain cereals for the primary or secondary prevention of cardiovascular disease | journal = The Cochrane Database of Systematic Reviews | volume = 8 | issue = 8 | pages = CD005051 | date = August 2017 | pmid = 28836672 | pmc = 6484378 | doi = 10.1002/14651858.CD005051.pub3 | url = https://spiral.imperial.ac.uk:8443/bitstream/10044/1/54579/2/Kelly_et_al-2017-.pdf | access-date = September 27, 2018 | url-status = dead | archive-url = https://web.archive.org/web/20180928044051/https://spiral.imperial.ac.uk:8443/bitstream/10044/1/54579/2/Kelly_et_al-2017-.pdf | archive-date = September 28, 2018 }}</ref>

===Classification===<!-- This title is used as a redirect target -->
The term ''complex carbohydrate'' was first used in the [[U.S. Senate Select Committee on Nutrition and Human Needs]] publication ''Dietary Goals for the United States'' (1977) where it was intended to distinguish sugars from other carbohydrates (which were perceived to be nutritionally superior).<ref>Joint WHO/FAO expert consultation (1998), ''Carbohydrates in human nutrition'', [http://www.fao.org/docrep/W8079E/w8079e07.htm chapter 1] {{Webarchive|url=https://web.archive.org/web/20070115102707/http://www.fao.org/docrep/w8079e/w8079e07.htm |date=January 15, 2007 }}. {{ISBN|92-5-104114-8}}.</ref> However, the report put "fruit, vegetables and whole-grains" in the complex carbohydrate column, despite the fact that these may contain sugars as well as polysaccharides. The standard usage, however, is to classify carbohydrates chemically: ''simple'' if they are sugars ([[monosaccharide]]s and [[disaccharide]]s) and ''complex'' if they are [[polysaccharide]]s (or [[oligosaccharide]]s).<ref name=lpi/><ref name=NutSource>{{cite web|title=Carbohydrates|url=http://www.hsph.harvard.edu/nutritionsource/carbohydrates/|work=The Nutrition Source|publisher=Harvard School of Public Health|access-date=April 3, 2013|date=September 18, 2012|archive-date=May 7, 2013|archive-url=https://web.archive.org/web/20130507074502/http://www.hsph.harvard.edu/nutritionsource/carbohydrates/|url-status=live}}</ref> Carbohydrates are sometimes divided into "available carbohydrates", which are absorbed in the [[small intestine]] and "unavailable carbohydrates", which pass to the [[large intestine]], where they are subject to [[fermentation]] by the [[Human gastrointestinal microbiota|gastrointestinal microbiota]].<ref name=lpi/>

====Glycemic index====
The [[glycemic index]] (GI) and [[glycemic load]] concepts characterize the potential for carbohydrates in food to raise [[blood glucose]] compared to a reference food (generally pure glucose).<ref name="lpi-gi">{{cite web |title=Glycemic Index and Glycemic Load |url=https://lpi.oregonstate.edu/mic/food-beverages/glycemic-index-glycemic-load |publisher=Micronutrient Information Center, Linus Pauling Institute, Oregon State University |access-date=19 January 2025 |date=2025}}</ref> Expressed numerically as GI, carbohydrate-containing foods can be grouped as high-GI (score more than 70), moderate-GI (56–69), or low-GI (less than 55) relative to pure glucose (GI=100).<ref name=lpi-gi/> Consumption of carbohydrate-rich, high-GI foods causes an abrupt increase in blood glucose concentration that declines rapidly following the meal, whereas low-GI foods with lower carbohydrate content produces a lower blood glucose concentration that returns gradually after the meal.<ref name=lpi-gi/>

[[Glycemic load]] is a measure relating the quality of carbohydrates in a food (low- vs. high-carbohydrate content &ndash; the GI) by the amount of carbohydrates in a single serving of that food.<ref name=lpi-gi/>

=== Health effects of dietary carbohydrate restriction ===

{{Main|Low-carbohydrate diet}}
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Low-carbohydrate diets may miss the health advantages – such as increased intake of [[dietary fiber]] and [[phytochemical]]s – afforded by high-quality plant foods such as [[legume]]s and [[pulse (legume)|pulses]], [[whole grain]]s, fruits, and vegetables.<ref name=mort>{{cite journal | vauthors = Seidelmann SB, Claggett B, Cheng S, Henglin M, Shah A, Steffen LM, Folsom AR, Rimm EB, Willett WC, Solomon SD | display-authors = 6 | title = Dietary carbohydrate intake and mortality: a prospective cohort study and meta-analysis | journal = The Lancet. Public Health | volume = 3 | issue = 9 | pages = e419–e428 | date = September 2018 | pmid = 30122560 | pmc = 6339822 | doi = 10.1016/s2468-2667(18)30135-x | type = Meta-analysis }}</ref><ref name=fibre>{{cite journal | vauthors = Reynolds A, Mann J, Cummings J, Winter N, Mete E, Te Morenga L | title = Carbohydrate quality and human health: a series of systematic reviews and meta-analyses | journal = Lancet | volume = 393 | issue = 10170 | pages = 434–445 | date = February 2019 | pmid = 30638909 | doi = 10.1016/S0140-6736(18)31809-9 | url = http://discovery.dundee.ac.uk/ws/files/30375889/Final_Lancet_for_John.pdf | access-date = April 24, 2022 | url-status = live | s2cid = 58632705 | doi-access = free | archive-url = https://web.archive.org/web/20210811080032/https://discovery.dundee.ac.uk/ws/files/30375889/Final_Lancet_for_John.pdf | archive-date = August 11, 2021 | type = Review }}</ref> A "meta-analysis, of moderate quality," included as adverse effects of the diet [[halitosis]], [[headache]] and [[constipation]].<ref name=obes>{{cite journal | vauthors = Churuangsuk C, Kherouf M, Combet E, Lean M | title = Low-carbohydrate diets for overweight and obesity: a systematic review of the systematic reviews | journal = Obesity Reviews | volume = 19 | issue = 12 | pages = 1700–1718 | date = December 2018 | pmid = 30194696 | doi = 10.1111/obr.12744 | url = http://eprints.gla.ac.uk/168899/1/168899.pdf | access-date = April 24, 2022 | url-status = live | type = Systematic review | s2cid = 52174104 | archive-url = https://web.archive.org/web/20190923071822/http://eprints.gla.ac.uk/168899/1/168899.pdf | archive-date = September 23, 2019 }}</ref>{{Better source needed|reason=Quoting source: "Only one meta-analysis, of moderate quality, reported adverse effects of LCDs [...]"|date=August 2022}}

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Carbohydrate-restricted diets can be as effective as low-fat diets in helping achieve weight loss over the short term when overall calorie intake is reduced.<ref name=endo>{{cite journal | vauthors = Schwartz MW, Seeley RJ, Zeltser LM, Drewnowski A, Ravussin E, Redman LM, Leibel RL | title = Obesity Pathogenesis: An Endocrine Society Scientific Statement | journal = Endocrine Reviews | volume = 38 | issue = 4 | pages = 267–296 | date = August 2017 | pmid = 28898979 | pmc = 5546881 | doi = 10.1210/er.2017-00111 }}</ref> An [[Endocrine Society]] scientific statement said that "when calorie intake is held constant [...] body-fat accumulation does not appear to be affected by even very pronounced changes in the amount of fat vs carbohydrate in the diet."<ref name=endo/> In the long term, low-carbohydrate diets do not appear to confer a "metabolic advantage," and effective weight loss or maintenance depends on the level of [[calorie restriction]],<ref name=endo/> not the ratio of [[macronutrient]]s in a diet.<ref name=tob>{{cite book |chapter=Behavioral approaches to the treatment of obesity |vauthors=Butryn ML, Clark VL, Coletta MC |title=Textbook of Obesity | veditors = Akabas SR, Lederman SA, Moore BJ |publisher=John Wiley & Sons|location=New York|year=2012 |quote=Taken together, these findings indicate that calorie intake, not macronutrient composition, determines long-term weight loss maintenance.|isbn=978-0-470-65588-7|page=259}}</ref> The reasoning of diet advocates that carbohydrates cause undue fat accumulation by increasing blood [[insulin]] levels, but a more balanced diet that restricts refined carbohydrates can also reduce serum glucose and insulin levels and may also suppress lipogenesis and promote fat oxidation.<ref>{{cite journal | vauthors =  Lopes da Silva MV, de Cassia Goncalves Alfenas R | title = Effect of the glycemic index on lipid oxidation and body composition | journal = Nutrición Hospitalaria | volume = 26 | issue = 1| pages = 48–55 | date = 2011 | doi = 10.3305/nh.2011.26.1.5008 | pmid = 21519729 }}</ref>  However, as far as energy expenditure itself is concerned, the claim that low-carbohydrate diets have a "metabolic advantage" is not supported by [[evidence-based medicine|clinical evidence]].<ref name=endo/><ref name=hall>{{cite journal | vauthors = Hall KD | title = A review of the carbohydrate-insulin model of obesity | journal = European Journal of Clinical Nutrition | volume = 71 | issue = 3 | pages = 323–326 | date = March 2017 | pmid = 28074888 | doi = 10.1038/ejcn.2016.260 | type = Review | s2cid = 54484172 }}</ref> Further, it is not clear how low-carbohydrate dieting affects [[cardiovascular health]], although two reviews showed that carbohydrate restriction may improve lipid markers of [[cardiovascular disease]] risk.<ref name=man>{{cite journal | vauthors = Mansoor N, Vinknes KJ, Veierød MB, Retterstøl K | title = Effects of low-carbohydrate diets v. low-fat diets on body weight and cardiovascular risk factors: a meta-analysis of randomised controlled trials | journal = The British Journal of Nutrition | volume = 115 | issue = 3 | pages = 466–479 | date = February 2016 | pmid = 26768850 | doi = 10.1017/S0007114515004699 | s2cid = 21670516 | doi-access = free }}</ref><ref name=ght>{{cite journal | vauthors = Gjuladin-Hellon T, Davies IG, Penson P, Amiri Baghbadorani R | title = Effects of carbohydrate-restricted diets on low-density lipoprotein cholesterol levels in overweight and obese adults: a systematic review and meta-analysis | journal = Nutrition Reviews | volume = 77 | issue = 3 | pages = 161–180 | date = March 2019 | pmid = 30544168 | doi = 10.1093/nutrit/nuy049 | url = http://researchonline.ljmu.ac.uk/id/eprint/8898/1/nutr-rev%20corrected%20version%2007072018.pdf | access-date = April 24, 2022 | url-status = live | type = Systematic review | s2cid = 56488132 | doi-access = free | archive-url = https://web.archive.org/web/20200506070047/http://researchonline.ljmu.ac.uk/id/eprint/8898/1/nutr-rev%20corrected%20version%2007072018.pdf | archive-date = May 6, 2020 }}</ref>

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Carbohydrate-restricted diets are no more effective than a conventional [[healthy diet]] in preventing the onset of [[type 2 diabetes]], but for people with type 2 diabetes, they are a viable option for losing weight or helping with [[glycemic control]].<ref name=brouns>{{cite journal | vauthors = Brouns F | title = Overweight and diabetes prevention: is a low-carbohydrate-high-fat diet recommendable? | journal = European Journal of Nutrition | volume = 57 | issue = 4 | pages = 1301–1312 | date = June 2018 | pmid = 29541907 | pmc = 5959976 | doi = 10.1007/s00394-018-1636-y | type = Review }}</ref><ref name=meng>{{cite journal | vauthors = Meng Y, Bai H, Wang S, Li Z, Wang Q, Chen L | title = Efficacy of low carbohydrate diet for type 2 diabetes mellitus management: A systematic review and meta-analysis of randomized controlled trials | journal = Diabetes Research and Clinical Practice | volume = 131 | pages = 124–131 | date = September 2017 | pmid = 28750216 | doi = 10.1016/j.diabres.2017.07.006 }}</ref><ref name=ada/> There is limited evidence to support routine use of low-carbohydrate dieting in managing [[type 1 diabetes]].<ref name=ups>{{cite journal | vauthors = Seckold R, Fisher E, de Bock M, King BR, Smart CE | title = The ups and downs of low-carbohydrate diets in the management of Type 1 diabetes: a review of clinical outcomes | journal = Diabetic Medicine | volume = 36 | issue = 3 | pages = 326–334 | date = March 2019 | pmid = 30362180 | doi = 10.1111/dme.13845 | type = Review | s2cid = 53102654 }}</ref> The [[American Diabetes Association]] recommends that people with diabetes should adopt a generally healthy diet, rather than a diet focused on carbohydrate or other macronutrients.<ref name=ada>{{cite journal | vauthors = ((American Diabetes Association Professional Practice Committee)) | title = 5. Lifestyle Management: ''Standards of Medical Care in Diabetes-2019'' | journal = Diabetes Care | volume = 42 | issue = Suppl 1 | pages = S46–S60 | date = January 2019 | pmid = 30559231 | doi = 10.2337/dc19-S005 | url = http://care.diabetesjournals.org/content/42/Supplement_1/S46 | access-date = April 24, 2022 | url-status = live | doi-access = free | archive-url = https://web.archive.org/web/20181218145626/http://care.diabetesjournals.org/content/42/Supplement_1/S46 | archive-date = December 18, 2018 }}</ref>

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An extreme form of low-carbohydrate diet – the [[ketogenic diet]] – is established as a medical diet for treating [[epilepsy]].<ref name=bda-2018/> Through [[celebrity endorsement]] during the early 21st century, it became a [[fad]] diet as a means of weight loss, but with risks of undesirable [[side effect]]s, such as low energy levels and increased hunger, [[insomnia]], nausea, and [[gastrointestinal]] discomfort.{{scientific citation needed|date=May 2023}}<ref name=bda-2018>{{cite web |publisher=British Dietetic Association |title=Top 5 worst celeb diets to avoid in 2018 |date=7 December 2017 |url=https://www.bda.uk.com/resource/top-5-worst-celeb-diets-to-avoid-in-2018.html |quote=The British Dietetic Association (BDA) today revealed its much-anticipated annual list of celebrity diets to avoid in 2018. The line-up this year includes Raw Vegan, Alkaline, Pioppi and Ketogenic diets as well as Katie Price's Nutritional Supplements. |access-date=1 December 2020 |archive-date=July 31, 2020 |archive-url=https://web.archive.org/web/20200731182316/https://www.bda.uk.com/resource/top-5-worst-celeb-diets-to-avoid-in-2018.html |url-status=live }}</ref> The [[British Dietetic Association]] named it one of the "top 5 worst celeb diets to avoid in 2018".<ref name=bda-2018/>