Low-carbohydrate diets restrict
carbohydrate
In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or ma ...
consumption relative to the average diet. Foods high in carbohydrates (e.g.,
sugar
Sugar is the generic name for sweet-tasting, soluble carbohydrates, many of which are used in food. Simple sugars, also called monosaccharides, include glucose, fructose, and galactose. Compound sugars, also called disaccharides or double ...
,
bread
Bread is a staple food prepared from a dough of flour (usually wheat) and water, usually by baking. Throughout recorded history and around the world, it has been an important part of many cultures' diet. It is one of the oldest human-made f ...
,
pasta
Pasta (, ; ) is a type of food typically made from an unleavened dough of wheat flour mixed with water or eggs, and formed into sheets or other shapes, then cooked by boiling or baking. Rice flour, or legumes such as beans or lentils, are som ...
) are limited, and replaced with foods containing a higher percentage of
fat
In nutrition science, nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such chemical compound, compounds, most commonly those that occur in living beings or in food.
The term often refers spec ...
and
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
(e.g.,
meat
Meat is animal flesh that is eaten as food. Humans have hunted, farmed, and scavenged animals for meat since prehistoric times. The establishment of settlements in the Neolithic Revolution allowed the domestication of animals such as chic ...
,
poultry
Poultry () are domesticated birds kept by humans for their eggs, their meat or their feathers. These birds are most typically members of the superorder Galloanserae (fowl), especially the order Galliformes (which includes chickens, quails, a ...
,
fish
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...
,
shellfish
Shellfish is a colloquial and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater envir ...
,
eggs
Humans and human ancestors have scavenged and eaten animal eggs for millions of years. Humans in Southeast Asia had domesticated chickens and harvested their eggs for food by 1,500 BCE. The most widely consumed eggs are those of fowl, especial ...
,
cheese
Cheese is a dairy product produced in wide ranges of flavors, textures, and forms by coagulation of the milk protein casein. It comprises proteins and fat from milk, usually the milk of cows, buffalo, goats, or sheep. During production, ...
,
nut
Nut often refers to:
* Nut (fruit), fruit composed of a hard shell and a seed, or a collective noun for dry and edible fruits or seeds
* Nut (hardware), fastener used with a bolt
Nut or Nuts may also refer to:
Arts, entertainment, and media Co ...
s, and
seeds
A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosperm pl ...
), as well as low carbohydrate foods (e.g.
spinach
Spinach (''Spinacia oleracea'') is a leafy green flowering plant native to central and western Asia. It is of the order Caryophyllales, family Amaranthaceae, subfamily Chenopodioideae. Its leaves are a common edible vegetable consumed either f ...
,
kale
Kale (), or leaf cabbage, belongs to a group of cabbage (''Brassica oleracea'') cultivars grown for their edible leaves, although some are used as ornamentals. Kale plants have green or purple leaves, and the central leaves do not form a head ...
,
chard
Chard or Swiss chard (; ''Beta vulgaris'' subsp. ''vulgaris'', Cicla Group and Flavescens Group) is a green leafy vegetable. In the cultivars of the Flavescens Group, the leaf stalks are large and often prepared separately from the leaf blade; ...
,
collards
Collard is a group of certain loose-leafed cultivars of ''Brassica oleracea'', the same species as many common vegetables including cabbage (Capitata group) and broccoli (Italica group). Collard is a member of the Viridis group of ''Brassica ol ...
, and other fibrous
vegetable
Vegetables are parts of plants that are consumed by humans or other animals as food. The original meaning is still commonly used and is applied to plants collectively to refer to all edible plant matter, including the flowers, fruits, stems, ...
s).
There is a lack of standardization of how much carbohydrate low-carbohydrate diets must have, and this has complicated research.
[ One definition, from the ]American Academy of Family Physicians
The American Academy of Family Physicians (AAFP) was founded in 1947 to promote and maintain high-quality standards for family medicine, an offshoot of the classical general practitioner. It is headquartered in Leawood, Kansas.
AAFP is one of ...
, specifies low-carbohydrate diets as having less than 20% of calories from carbohydrates.
There is no good evidence that low-carbohydrate dieting confers any particular health benefits apart from weight loss
Weight loss, in the context of medicine, health, or physical fitness, refers to a reduction of the total body mass, by a mean loss of fluid, body fat (adipose tissue), or lean mass (namely bone mineral deposits, muscle, tendon, and other conn ...
, where low-carbohydrate diets achieve outcomes similar to other diets, as weight loss is mainly determined by calorie restriction
Calorie restriction (caloric restriction or energy restriction) is a dietary regimen that reduces intake of energy from caloric foods & beverages without incurring malnutrition. "Reduce" can be defined relative to the subject's previous intake be ...
and adherence.
An extreme form of low-carbohydrate diet called the ketogenic diet
The ketogenic diet is a high- fat, adequate-protein, low-carbohydrate dietary therapy that in conventional medicine is used mainly to treat hard-to-control (refractory) epilepsy in children. The diet forces the body to burn fats rather than ca ...
was first established as a medical diet for treating epilepsy
Epilepsy is a group of non-communicable neurological disorders characterized by recurrent epileptic seizures. Epileptic seizures can vary from brief and nearly undetectable periods to long periods of vigorous shaking due to abnormal electrical ...
. It became a popular fad diet
A fad diet is a diet that becomes popular for a short time, similar to fads in fashion, without being a standard dietary recommendation, and often making unreasonable claims for fast weight loss or health improvements. There is no single defini ...
for weight loss through celebrity endorsement
Celebrity branding or celebrity endorsement is a form of advertising campaign or marketing strategy which uses a celebrity's fame or social status to promote a product, brand or service, or to raise awareness about an issue. Marketers use celebr ...
, but there is no evidence of any distinctive benefit for this purpose and the diet carries a risk of adverse effect
An adverse effect is an undesired harmful effect resulting from a medication or other intervention, such as surgery. An adverse effect may be termed a "side effect", when judged to be secondary to a main or therapeutic effect. The term complica ...
s,[Kossoff EH, Wang HS]
Dietary therapies for epilepsy.
Biomed J. 2013 Jan-Feb;36(1):2-8. with the British Dietetic Association
The British Dietetic Association (BDA) is a professional association and trade union for dietitians in the United Kingdom. It was founded in 1936 and became a certified union in 1982: it is affiliated to the Trades Union Congress and the Scottis ...
naming it one of the "top five worst celeb diets to avoid" in 2018.[
]
Definition and classification
Macronutrient ratios
The macronutrient ratios of low-carbohydrate diets are not standardized. , the conflicting definitions of "low-carbohydrate" diets have complicated research into the subject.[
The National Lipid Association and Lifestyle Task force define low-carbohydrate diets and those containing less than 25% of calories from carbohydrates, and very low carbohydrate diets being those containing less than 10% carbohydrates. A 2016 ]review
A review is an evaluation of a publication, product, service, or company or a critical take on current affairs in literature, politics or culture. In addition to a critical evaluation, the review's author may assign the work a content rating, ...
of low-carbohydrate diets classified diets with 50 g of carbohydrate per day (less than 10% of total calories) as "very low" and diets with 40% of calories from carbohydrates as "mild" low-carbohydrate diets. The UK National Health Service
The National Health Service (NHS) is the umbrella term for the publicly funded healthcare systems of the United Kingdom (UK). Since 1948, they have been funded out of general taxation. There are three systems which are referred to using the " ...
recommend that "carbohydrates should be the body's main source of energy in a healthy, balanced diet."[
]
Foodstuffs
There is evidence that the quality, rather than the quantity, of carbohydrate in a diet is important for health, and that high-fiber slow-digesting carbohydrate-rich foods are healthful while highly refined and sugary foods are less so. People choosing diet for health conditions should have their diet tailored to their individual requirements. For people with metabolic conditions, a diet with approximately 40–50% carbohydrate is recommended.
Most vegetables are low- or moderate-carbohydrate foods (in some low-carbohydrate diets, fiber
Fiber or fibre (from la, fibra, links=no) is a natural or artificial substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorporate ...
is excluded because it is not a nutritive carbohydrate). Some vegetables, such as potato
The potato is a starchy food, a tuber of the plant ''Solanum tuberosum'' and is a root vegetable native to the Americas. The plant is a perennial in the nightshade family Solanaceae.
Wild potato species can be found from the southern Unit ...
es, carrots
The carrot (''Daucus carota'' subsp. ''sativus'') is a root vegetable, typically orange in color, though purple, black, red, white, and yellow cultivars exist, all of which are domesticated forms of the wild carrot, ''Daucus carota'', nativ ...
, maize
Maize ( ; ''Zea mays'' subsp. ''mays'', from es, maíz after tnq, mahiz), also known as corn (North American and Australian English), is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. Th ...
(corn) and rice are high in starch. Most low-carbohydrate diet plans accommodate vegetables such as broccoli
Broccoli (''Brassica oleracea'' var. ''italica'') is an edible green plant in the cabbage family (family Brassicaceae, genus ''Brassica'') whose large flowering head, stalk and small associated leaves are eaten as a vegetable. Broccoli is cl ...
, spinach
Spinach (''Spinacia oleracea'') is a leafy green flowering plant native to central and western Asia. It is of the order Caryophyllales, family Amaranthaceae, subfamily Chenopodioideae. Its leaves are a common edible vegetable consumed either f ...
, kale
Kale (), or leaf cabbage, belongs to a group of cabbage (''Brassica oleracea'') cultivars grown for their edible leaves, although some are used as ornamentals. Kale plants have green or purple leaves, and the central leaves do not form a head ...
, lettuce
Lettuce (''Lactuca sativa'') is an annual plant of the family Asteraceae. It is most often grown as a leaf vegetable, but sometimes for its stem and seeds. Lettuce is most often used for salads, although it is also seen in other kinds of food, ...
, cucumbers
Cucumber (''Cucumis sativus'') is a widely-cultivated creeping vine plant in the Cucurbitaceae family that bears usually cylindrical fruits, which are used as culinary vegetables.[cauliflower
Cauliflower is one of several vegetables in the species ''Brassica oleracea'' in the genus ''Brassica'', which is in the Brassicaceae (or mustard) family. It is an annual plant that reproduces by seed. Typically, only the head is eaten – the ...]
, Brussels sprouts
The Brussels sprout is a member of the Gemmifera cultivar group of cabbages (''Brassica oleracea''), grown for its edible buds. The leaf vegetables are typically 1.5–4.0 cm (0.6–1.6 in) in diameter and resemble miniature cabbages ...
, peppers
Pepper or peppers may refer to:
Food and spice
* Piperaceae or the pepper family, a large family of flowering plant
** Black pepper
* ''Capsicum'' or pepper, a genus of flowering plants in the nightshade family Solanaceae
** Bell pepper
** Chili ...
and most green-leafy vegetables.
Adoption and advocacy
The National Academy of Medicine
The National Academy of Medicine (NAM), formerly called the Institute of Medicine (IoM) until 2015, is an American nonprofit, non-governmental organization. The National Academy of Medicine is a part of the National Academies of Sciences, En ...
recommends a daily average of 130 g of carbohydrates per day. The FAO
The Food and Agriculture Organization of the United Nations (FAO)french: link=no, Organisation des Nations unies pour l'alimentation et l'agriculture; it, Organizzazione delle Nazioni Unite per l'Alimentazione e l'Agricoltura is an intern ...
and WHO
Who or WHO may refer to:
* Who (pronoun), an interrogative or relative pronoun
* Who?, one of the Five Ws in journalism
* World Health Organization
Arts and entertainment Fictional characters
* Who, a creature in the Dr. Seuss book '' Horton He ...
similarly recommend that the majority of dietary energy come from carbohydrates. Low-carbohydrate diets are not an option recommended in the 2015–2020 edition of Dietary Guidelines for Americans The Dietary Guidelines for Americans (DGA) provide nutritional advice for Americans who are healthy or who are at risk for chronic disease but do not currently have chronic disease. The Guidelines are published every five years by the US Department ...
, which instead recommends a low-fat diet.
Carbohydrate has been wrongly accused of being a uniquely "fattening" macronutrient
A nutrient is a substance used by an organism to survive, grow, and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi, and protists. Nutrients can be incorporated into cells for metabolic purposes or excret ...
, misleading many dieters into compromising the nutritiousness of their diet by eliminating carbohydrate-rich food. Low-carbohydrate diet proponents emphasize research saying that low-carbohydrate diets can initially cause slightly greater weight loss than a balanced diet, but any such advantage does not persist.[ In the long-term successful weight maintenance is determined by calorie intake, and not by macronutrient ratios.][
The public has become confused by the way in which some diets, such as the ]Zone diet
The Zone diet is a fad diet emphasizing low-carbohydrate consumption. It was created by Barry Sears, an American biochemist.Baron M. Fighting obesity Part 1: Review of popular low-carb diets. Health Care Food Nutr Focus. 2004 Oct;21(10):1, 3-6, 1 ...
and the South Beach diet
The South Beach Diet is a popular fad diet developed by Arthur Agatston and promoted in a best-selling 2003 book.Sandra Bastin for University of Kentucky Extension Service. August 1998; revised March 2004University of Kentucky Extension Service: F ...
are promoted as "low-carbohydrate" when in fact they would more properly be termed "medium-carbohydrate" diets.[
]
Carbohydrate-insulin hypothesis
Low-carbohydrate diet advocates including Gary Taubes
Gary Taubes (born April 30, 1956) is an American journalist, writer, and low-carbohydrate / high-fat (LCHF) diet advocate. His central claim is that carbohydrates, especially sugar and high-fructose corn syrup, overstimulate the secretion of insu ...
and David Ludwig David Ludwig may refer to:
* David Ludwig (physician), American physician
* David Ludwig (composer) (born 1974), American composer
{{Hndis, Ludwig, David ...
have proposed a "carbohydrate-insulin hypothesis" in which carbohydrates are said to be uniquely fattening because they raise insulin levels and cause fat to accumulate unduly. The hypothesis appears to run counter to known human biology whereby there is no good evidence of any such association between the actions of insulin, fat accumulation, and obesity.[ The hypothesis predicted that low-carbohydrate dieting would offer a "metabolic advantage" of increased energy expenditure equivalent to 400–600 kcal(kilocalorie)/day, in accord with the promise of the ]Atkin's diet
The Atkins diet is a Low-carbohydrate diet, low-carbohydrate fad diet devised by Robert Atkins (physician), Robert Atkins in the 1970s, marketed with claims that carbohydrate restriction is crucial to weight loss and that the diet offered "a high ...
: a "high calorie way to stay thin forever".[
With funding from the ]Laura and John Arnold Foundation
Arnold Ventures LLC (formerly known as The Laura and John Arnold Foundation) is focused on evidence-based giving in a wide range of categories including: criminal justice, education, health care, and public finance. The organization was founded by ...
, in 2012, Taubes co-founded the Nutrition Science Initiative (NuSI), with the aim of raising over $200 million to undertake a "Manhattan Project
The Manhattan Project was a research and development undertaking during World War II that produced the first nuclear weapons. It was led by the United States with the support of the United Kingdom and Canada. From 1942 to 1946, the project w ...
For Nutrition" and validate the hypothesis. Intermediate results, published in the ''American Journal of Clinical Nutrition
''The American Journal of Clinical Nutrition'' (''AJCN'') is a monthly peer-reviewed biomedical journal in the fields of dietetics and clinical nutrition.
The journal was established in 1952 as the ''Journal of Clinical Nutrition'', edited by S ...
'' did not provide convincing evidence of any advantage to a low-carbohydrate diet as compared to diets of other composition. This study revealed a marginal (∼100 kcal/d) but statistically significant effect of the ketogenic diet to increase 24-hour energy expenditure measured in a respiratory chamber, but the effect waned over time. Ultimately a very low-calorie, ketogenic diet (of 5% carbohydrate) "was not associated with significant loss of fat mass" compared to a non-specialized diet with the same calories; there was no useful "metabolic advantage".[ In 2017, Kevin Hall, a ]National Institutes of Health
The National Institutes of Health, commonly referred to as NIH (with each letter pronounced individually), is the primary agency of the United States government responsible for biomedical and public health research. It was founded in the late ...
researcher hired to assist with the project, wrote that the carbohydrate-insulin hypothesis had been falsified by experiment. Hall wrote "the rise in obesity prevalence may be primarily due to increased consumption of refined carbohydrates, but the mechanisms are likely to be quite different from those proposed by the carbohydrate–insulin model."[
]
Health aspects
Adherence
It has been repeatedly found that in the long-term, all diets with the same calorific value perform the same for weight loss, except for the one differentiating factor of how well people can faithfully follow the dietary programme. A study comparing groups taking low-fat, low-carbohydrate and Mediterranean diet
The Mediterranean diet is a diet inspired by the eating habits of people who live near the Mediterranean Sea. When initially formulated in the 1960s, it drew on the cuisines of Greece, Italy, France and Spain. In decades since, it has also incor ...
s found at six months the low-carbohydrate diet still had most people adhering to it, but thereafter the situation reversed: at two years the low-carbohydrate group had the highest incidence of lapses and dropouts.[ This may be due to the comparatively limited food choice of low-carbohydrate diets.][
]
Body weight
In the short and medium term, people taking a low-carbohydrate diet can experience more weight loss than people taking a low-fat diet
A low-fat diet is one that restricts fat, and often saturated fat and cholesterol as well. Low-fat diets are intended to reduce the occurrence of conditions such as heart disease and obesity. For weight loss, they perform similarly to a low-carb ...
. The Endocrine Society
The Endocrine Society is a professional, international medical organization in the field of endocrinology and metabolism, founded in 1916 as The Association for the Study of Internal Secretions. The official name of the organization was changed ...
stated 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". People on such a diet have very slightly more weight loss initially, equivalent to approximately 100kcal/day, but that the advantage diminishes over time and is ultimately insignificant.[ A Cochrane review from 2022 looked into longer periods of two years and found no benefit for adhering to a low-carbohydrate diet in comparison to balanced diets.][
Much of the research comparing low-fat vs. low-carbohydrate dieting has been of poor quality and studies which reported large effects have garnered disproportionate attention in comparison to those which are methodologically sound.][ A 2018 review said "higher-quality meta-analyses reported little or no difference in weight loss between the two diets."][ Low-quality ]meta-analyses
A meta-analysis is a statistical analysis that combines the results of multiple scientific studies. Meta-analyses can be performed when there are multiple scientific studies addressing the same question, with each individual study reporting me ...
have tended to report favourably on the effect of low-carbohydrate diets: a systematic review
A systematic review is a Literature review, scholarly synthesis of the evidence on a clearly presented topic using critical methods to identify, define and assess research on the topic. A systematic review extracts and interprets data from publ ...
reported that 8 out of 10 meta-analyses assessed whether weight loss outcomes could have been affected by publication bias
In published academic research, publication bias occurs when the outcome of an experiment or research study biases the decision to publish or otherwise distribute it. Publishing only results that show a significant finding disturbs the balance o ...
, and 7 of them concluded positively.[ A 2017 review concluded that a variety of diets, including low-carbohydrate diets, achieve similar weight loss outcomes, which are mainly determined by ]calorie restriction
Calorie restriction (caloric restriction or energy restriction) is a dietary regimen that reduces intake of energy from caloric foods & beverages without incurring malnutrition. "Reduce" can be defined relative to the subject's previous intake be ...
and adherence rather than the type of diet.
Cardiovascular health
Eating a low-carbohydrate diet for less than two years was found to not worsen markers for cardiovascular health. However, following a low-carb diet for many years is associated with dying from heart disease. Low-carbohydrate diets in the long-term have detrimental effects on lipid parameters such as increase in total and LDL cholesterol. This is because most people on low-carbohydrate diets eat more animal source foods
Animal source foods (ASF) include many food items that come from an animal source such as fish, meat, milk, eggs, honey, cheese and yogurt. Many individuals do not consume ASF or consume little ASF by either personal choice or necessity, as ASF m ...
and less fruits and vegetables rich in fiber
Fiber or fibre (from la, fibra, links=no) is a natural or artificial substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorporate ...
and micronutrients.
The American College of Cardiology
The American College of Cardiology (ACC), based in Washington, D.C., is a nonprofit medical association established in 1949. It bestows credentials upon cardiovascular specialists who meet its qualifications. Education is a core component of the ...
recommends a clinician-patient discussion for people who want to go on a very low-carbohydrate diet. People on the diet should be informed that it may worsen LDL-C levels and cardiovascular health in the long-term. Those with atherosclerosis should be counseled to avoid low-carbohydrate diets.
Diabetes
There is limited evidence for the effectiveness of low-carbohydrate diets for people with type 1 diabetes
Type 1 diabetes (T1D), formerly known as juvenile diabetes, is an autoimmune disease that originates when cells that make insulin (beta cells) are destroyed by the immune system. Insulin is a hormone required for the cells to use blood sugar for ...
.[ For certain individuals, it may be feasible to follow a low-carbohydrate regime combined with carefully managed ]insulin
Insulin (, from Latin ''insula'', 'island') is a peptide hormone produced by beta cells of the pancreatic islets encoded in humans by the ''INS'' gene. It is considered to be the main anabolic hormone of the body. It regulates the metabolism o ...
dosing. This can be hard to maintain and there are concerns about potential adverse health effects caused by the diet.[ In general, people with type 1 diabetes are advised to follow an individualized eating plan.]
The proportion of carbohydrate in a diet is not linked to the risk of type 2 diabetes
Type 2 diabetes, formerly known as adult-onset diabetes, is a form of diabetes mellitus that is characterized by high blood sugar, insulin resistance, and relative lack of insulin. Common symptoms include increased thirst, frequent urination, ...
, although there is some evidence that diets containing certain high-carbohydrate items – such as sugar-sweetened drinks or white rice – are associated with an increased risk. Some evidence indicates that consuming fewer carbohydrate foods may reduce biomarker
In biomedical contexts, a biomarker, or biological marker, is a measurable indicator of some biological state or condition. Biomarkers are often measured and evaluated using blood, urine, or soft tissues to examine normal biological processes, ...
s of type 2 diabetes.
A 2019 consensus report on nutrition therapy for adults with diabetes and prediabetes the American Diabetes Association
The American Diabetes Association (ADA) is a United States-based nonprofit that seeks to educate the public about diabetes and to help those affected by it through funding research to manage, cure and prevent diabetes (including type 1 diabetes, ...
(ADA) states "Reducing overall carbohydrate intake for individuals with diabetes has demonstrated the most evidence for improving glycemia (blood sugar) and may be applied in a variety of eating patterns that meet individual needs and preferences." However, another source states that there is no good evidence that low-carbohydrate diets are better than a conventional healthy diet
A healthy diet is a diet that maintains or improves overall health. A healthy diet provides the body with essential nutrition: fluid, macronutrients such as protein, micronutrients such as vitamins, and adequate fibre and food energy.
A healthy ...
in which carbohydrates typically account for more than 40% of calories consumed. Low-carbohydrate dieting has no effect on the kidney function
Assessment of kidney function occurs in different ways, using the presence of symptoms and signs, as well as measurements using urine tests, blood tests, and medical imaging.
Functions of a healthy kidney include maintaining a person's fluid ...
of people who have type 2 diabetes.
Limiting carbohydrate consumption generally results in improved glucose control, although without long-term weight loss. Low-carbohydrate diets can be useful to help people with type 2 diabetes lose weight, but "no single approach has been proven to be consistently superior." According to the ADA, people with diabetes should be "developing healthy eating patterns rather than focusing on individual macronutrients, micronutrients, or single foods." They recommended that the carbohydrates in a diet should come from "vegetables, legumes, fruits, dairy (milk and yogurt), and whole grains", while highly refined foods and sugary drinks should be avoided.[ The ADA also wrote that "reducing overall carbohydrate intake for individuals with diabetes has demonstrated the most evidence for improving glycemia and may be applied in a variety of eating patterns that meet individual needs and preferences." For individuals with type 2 diabetes who can't meet the glycemic targets or where reducing anti-glycemic medications is a priority, the ADA says that low or very-low carbohydrate diets are a viable approach.
A 2021 umbrella review found that low-carbohydrate diets are no better for weight loss than higher-carbohydrate or low-fat diets in diabetic patients.
]
Exercise and fatigue
A low-carbohydrate diet has been found to reduce endurance
Endurance (also related to sufferance, resilience, constitution, fortitude, and hardiness) is the ability of an organism to exert itself and remain active for a long period of time, as well as its ability to resist, withstand, recover from a ...
capacity for intense exercise efforts, and depleted muscle glycogen
Glycogen is a multibranched polysaccharide of glucose that serves as a form of energy storage in animals, fungi, and bacteria. The polysaccharide structure represents the main storage form of glucose in the body.
Glycogen functions as one o ...
following such efforts is only slowly replenished if a low-carbohydrate diet is taken. Inadequate carbohydrate intake during athletic training causes metabolic acidosis
Metabolic acidosis is a serious electrolyte disorder characterized by an imbalance in the body's acid-base balance. Metabolic acidosis has three main root causes: increased acid production, loss of bicarbonate, and a reduced ability of the kidneys ...
, which may be responsible for the impaired performance which has been observed.
Safety
A low-carbohydrate diet causes extensive metabolism of fatty acids, which are used by the liver to make ketone bodies
Ketone bodies are water-soluble molecules that contain the ketone groups produced from fatty acids by the liver (ketogenesis). Ketone bodies are readily transported into tissues outside the liver, where they are converted into acetyl-CoA (acetyl- ...
, which provide energy to important organs, including the brain, heart, and kidneys, in a condition called ketosis
Ketosis is a metabolic state characterized by elevated levels of ketone bodies in the blood or urine. Physiological ketosis is a normal response to low glucose availability, such as low-carbohydrate diets or fasting, that provides an additional ...
. Ketosis can have other causes such as alcoholism
Alcoholism is, broadly, any drinking of alcohol (drug), alcohol that results in significant Mental health, mental or physical health problems. Because there is disagreement on the definition of the word ''alcoholism'', it is not a recognize ...
and diabetes
Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ap ...
. Excessive accumulation of ketone bodies occurs when its production is greater than consumption, leading to ketoacidosis
Ketoacidosis is a metabolic state caused by uncontrolled production of ketone bodies that cause a metabolic acidosis. While ketosis refers to any elevation of blood ketones, ketoacidosis is a specific pathologic condition that results in changes ...
, a potentially life-threatening condition. Rarely, a low-carbohydrate ketogenic diet can also give rise to ketoacidosis, especially in patients with comorbid conditions. There are infrequent case reports of ketoacidosis occurring in people who follow low-carbohydrate diets such as the Atkins Atkins may refer to:
Places in the United States
* Atkins, Arkansas, a city
* Atkins, Iowa, a city
* Atkins, Louisiana, an unincorporated community
* Atkins, Nebraska, an unincorporated community
* Atkins, Virginia, a census-designated place
* ...
and South Beach diets. This has led to the suggestion that ketoacidosis should be considered a potential hazard of low-carbohydrate dieting.
High and low-carbohydrate diets that are rich in animal-derived proteins and fats may be associated with increased mortality. Conversely, with plant-derived proteins and fats, there may be a decrease of mortality. A 2021 study from Japan looked at the long-term aspects of low-carb eating. The study included 90,171 participants with a median 17 years of follow-up. The study found that a high adherence to low-carb eating was associated with increased overall cancer risk. Looking at the diet composition the authors found that eating more animals foods was associated with an increased cancer risk while plant fat consumption was not.
, research has paid insufficient attention to the potential adverse effect
An adverse effect is an undesired harmful effect resulting from a medication or other intervention, such as surgery. An adverse effect may be termed a "side effect", when judged to be secondary to a main or therapeutic effect. The term complica ...
s of carbohydrate restricted dieting, particularly for micronutrient
Micronutrients are nutrient, essential dietary elements required by organisms in varying quantities throughout life to orchestrate a range of physiological functions to maintain health. Micronutrient requirements differ between organisms; for exam ...
sufficiency, bone health
The human skeletal system is a complex organ in constant equilibrium with the rest of the body. In addition to support and structure of the body, bone is the major reservoir for many minerals and compounds essential for maintaining a healthy pH ...
and cancer
Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...
risk. One low-quality meta-analysis reported that adverse effects could include "constipation
Constipation is a bowel dysfunction that makes bowel movements infrequent or hard to pass. The stool is often hard and dry. Other symptoms may include abdominal pain, bloating, and feeling as if one has not completely passed the bowel movement ...
, headache
Headache is the symptom of pain in the face, head, or neck. It can occur as a migraine, tension-type headache, or cluster headache. There is an increased risk of depression in those with severe headaches.
Headaches can occur as a result ...
, halitosis
Bad breath, also known as halitosis, is a symptom in which a noticeably unpleasant breath odour is present. It can result in anxiety among those affected. It is also associated with depression and symptoms of obsessive compulsive disorder.
Th ...
, muscle cramps
A cramp is a sudden, involuntary, painful skeletal muscle contraction or overshortening associated with electrical activity; while generally temporary and non-damaging, they can cause significant pain and a paralysis-like immobility of the af ...
and general weakness".[
In a comprehensive ]systematic review
A systematic review is a Literature review, scholarly synthesis of the evidence on a clearly presented topic using critical methods to identify, define and assess research on the topic. A systematic review extracts and interprets data from publ ...
of 2018, Churuangsuk and colleagues reported that other case report In medicine, a case report is a detailed report of the symptoms, signs, diagnosis, treatment, and follow-up of an individual patient. Case reports may contain a demographic profile of the patient, but usually describe an unusual or novel occurrence ...
s give rise to concerns of other potential risks of low-carbohydrate dieting including hyperosmolar coma
Diabetic coma is a life-threatening but reversible form of coma found in people with diabetes mellitus.
Three different types of diabetic coma are identified:
#Severe low blood sugar in a diabetic person
#Diabetic ketoacidosis (usually type 1 ...
, Wernicke's encephalopathy, optic neuropathy Optic neuropathy is damage to the optic nerve from any cause. The optic nerve is a bundle of millions of fibers in the retina that sends visual signals to the brain.
Damage and death of these nerve cells, or neurons, leads to characteristic featu ...
from thiamine deficiency
Thiamine deficiency is a medical condition of low levels of thiamine (Vitamin B1). A severe and chronic form is known as beriberi. The two main types in adults are wet beriberi and dry beriberi. Wet beriberi affects the cardiovascular system, r ...
, acute coronary syndrome
Acute coronary syndrome (ACS) is a syndrome (a set of signs and symptoms) due to decreased blood flow in the coronary arteries such that part of the heart muscle is unable to function properly or dies. The most common symptom is centrally loca ...
and anxiety disorder
Anxiety disorders are a cluster of mental disorders characterized by significant and uncontrollable feelings of anxiety and fear such that a person's social, occupational, and personal function are significantly impaired. Anxiety may cause physi ...
.
Significantly restricting the proportion of carbohydrate in diet risks causing malnutrition
Malnutrition occurs when an organism gets too few or too many nutrients, resulting in health problems. Specifically, it is "a deficiency, excess, or imbalance of energy, protein and other nutrients" which adversely affects the body's tissues a ...
, and can make it difficult to get enough dietary fiber
Dietary fiber (in British English fibre) or roughage is the portion of plant-derived food that cannot be completely broken down by human digestive enzymes. Dietary fibers are diverse in chemical composition, and can be grouped generally by the ...
to stay healthy.
As of 2014, it appeared that with respect to the risk of death for people with cardiovascular disease, the kind of carbohydrates consumed are important; diets relatively higher in fiber and whole grains lead to reduced risk of death from cardiovascular disease compared to diets high in refined grains.
History
First descriptions
In 1797, John Rollo
John Rollo M.D. (d. December 23, 1809) was a Scottish military surgeon, now known for his work on a diabetic diet. Rollo was the first to suggest a low-carbohydrate diet as a treatment for diabetes.Veves, Aristidis; Malik, Rayaz A. (2007). ''Diabe ...
reported on the results of treating two diabetic
Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level (hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased app ...
Army officers with a low-carbohydrate diet and medications. A very low-carbohydrate diet was the standard treatment for diabetes throughout the nineteenth century.
In 1863, William Banting, a formerly obese English undertaker and coffin maker, published "Letter on Corpulence Addressed to the Public", in which he described a diet for weight control giving up bread
Bread is a staple food prepared from a dough of flour (usually wheat) and water, usually by baking. Throughout recorded history and around the world, it has been an important part of many cultures' diet. It is one of the oldest human-made f ...
, butter
Butter is a dairy product made from the fat and protein components of churned cream. It is a semi-solid emulsion at room temperature, consisting of approximately 80% butterfat. It is used at room temperature as a spread, melted as a condiment ...
, milk
Milk is a white liquid food produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals (including breastfed human infants) before they are able to digestion, digest solid food. Immune factors and immune ...
, sugar
Sugar is the generic name for sweet-tasting, soluble carbohydrates, many of which are used in food. Simple sugars, also called monosaccharides, include glucose, fructose, and galactose. Compound sugars, also called disaccharides or double ...
, beer
Beer is one of the oldest and the most widely consumed type of alcoholic drink in the world, and the third most popular drink overall after water and tea. It is produced by the brewing and fermentation of starches, mainly derived from ce ...
, and potatoes
The potato is a starchy food, a tuber of the plant ''Solanum tuberosum'' and is a root vegetable native to the Americas. The plant is a perennial in the nightshade family Solanaceae.
Wild potato species can be found from the southern United ...
. His booklet was widely read, so much so that some people used the term "Banting" for the activity now called "dieting
Dieting is the practice of eating food in a regulated way to decrease, maintain, or increase body weight, or to prevent and treat diseases such as diabetes and obesity. As weight loss depends on calorie intake, different kinds of calorie-redu ...
".
Physicians who advocated a low-carbohydrate diet consisting of large amounts of animal fat and protein to treat diabetes in the late 1800s include James Lomax Bardsley
Sir James Lomax Bardsley, M.D. (7 July 1801 – 10 July 1876) was an English physician.
Life
Bardsley was born at Nottingham on 7 July 1801. His professional education was first under the direction of his uncle, Dr. Samuel Argent Bardsley, and su ...
, Apollinaire Bouchardat
Apollinaire Bouchardat (July 23, 1809 – April 7, 1886) was a French pharmacist and hygienist born in L'Isle-sur-Serein.
Biography
He studied at the Ecole de pharmacie de Paris and the Muséum d'Histoire Naturelle, and later became chief p ...
and Frederick William Pavy
Frederick William Pavy (29 May 1829 – 19 September 1911) was a British physician and physiologist and the discoverer of Pavy disease, a cyclic or recurrent physiologic albuminuria.
Life
Pavy was born in Wroughton and educated at Merc ...
. Arnaldo Cantani isolated his diabetic patients in locked rooms and prescribed them an exclusive animal-based diet.
In the early 1900s Frederick Madison Allen
Frederick Madison Allen (16 March 1879 – 14 April 1957) was a physician who is best remembered for his carbohydrate-restricted low-calorie diet for sufferers of diabetes mellitus. He was known for pioneering the "starvation diet".
Life
Bor ...
developed a highly restrictive short term regime which was described by Walter R. Steiner at the 1916 annual convention of the Connecticut State Medical Society as ''The Starvation Treatment of Diabetes Mellitus''. This diet was often administered in a hospital in order to better ensure compliance and safety.[
]
Modern low-carbohydrate diets
Other low-carbohydrate diets in the 1960s included the Air Force diet, "Martinis & Whipped Cream" in 1966, and the Drinking Man's Diet. In 1972, Robert Atkins published '' Dr. Atkins' Diet Revolution'', which advocated the low-carbohydrate diet he had successfully used in treating people in the 1960s. The book was a publishing success, but was widely criticized by the mainstream medical community as being dangerous and misleading, thereby limiting its appeal at the time.
The concept of the glycemic index
The glycemic (glycaemic) index (GI; ) is a number from 0 to 100 assigned to a food, with pure glucose arbitrarily given the value of 100, which represents the relative rise in the blood glucose level two hours after consuming that food. The GI of ...
was developed in 1981 by David Jenkins to account for variances in speed of digestion of different types of carbohydrates. This concept classifies foods according to the rapidity of their effect on blood sugar
Glycaemia, also known as blood sugar level, blood sugar concentration, or blood glucose level is the measure of glucose concentrated in the blood of humans or other animals. Approximately 4 grams of glucose, a simple sugar, is present in the blo ...
levelswith fast-digesting simple carbohydrates causing a sharper increase and slower-digesting complex carbohydrate
In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or may ...
s, such as whole grain
A whole grain is a grain of any cereal and pseudocereal that contains the endosperm, germ, and bran, in contrast to refined grains, which retain only the endosperm.
As part of a general healthy diet, consumption of whole grains is associated w ...
s, a slower one. Jenkins's research laid the scientific groundwork for subsequent low-carbohydrate diets.
In 1992, Atkins published an update from his 1972 book, ''Dr. Atkins' New Diet Revolution'', and other doctors began to publish books based on the same principles. During the late 1990s and early 2000s, low-carbohydrate diets became some of the most popular diets in the US. By some accounts, up to 18% of the population was using one type of low-carbohydrate diet or another at the peak of their popularity. Food manufacturers
Food is any substance consumed by an organism for nutritional support. Food is usually of plant, animal, or fungal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals. The substance is ing ...
and restaurant chain
A chain store or retail chain is a retail outlet in which several locations share a brand, central management and standardized business practices. They have come to dominate the retail and dining markets and many service categories, in many pa ...
s noted the trend, as it affected their businesses. Parts of the mainstream medical community have denounced low-carbohydrate diets as being dangerous to health, such as the AHA in 2001 and the American Kidney Fund
The American Kidney Fund (AKF) is a publicly supported non-profit organization founded in 1971.
The AKF provides comprehensive programs of kidney health awareness, education, and prevention. It provides financial assistance that helps 1 out of ...
in 2002.
Ketogenic diet
The original ketogenic diet
The ketogenic diet is a high- fat, adequate-protein, low-carbohydrate dietary therapy that in conventional medicine is used mainly to treat hard-to-control (refractory) epilepsy in children. The diet forces the body to burn fats rather than ca ...
is a high-fat, low-carbohydrate diet developed in the 1920s and used to treat drug-resistant childhood epilepsy
Epilepsy is a group of non-communicable neurological disorders characterized by recurrent epileptic seizures. Epileptic seizures can vary from brief and nearly undetectable periods to long periods of vigorous shaking due to abnormal electrical ...
. Most epilepsy specialists order these children to eat 80% of the diet from fat by weight (90% of calories), plus carbohydrate-free vitamins and minerals to prevent vitamin deficiency
Vitamin deficiency is the condition of a long-term lack of a vitamin. When caused by not enough vitamin intake it is classified as a ''primary deficiency'', whereas when due to an underlying disorder such as malabsorption it is called a ''seconda ...
. Although this extreme diet plan can be life-saving compared to the alternative, it is not a harmless diet. Children on this diet are at risk of broken bones, stunted growth, kidney stones, high cholesterol, and micronutrient deficiency
Micronutrient deficiency or dietary deficiency is not enough of one or more of the micronutrients required for optimal plant or animal health. In humans and other animals they include both vitamin deficiencies and mineral deficiencies, whereas in ...
. It is not known how long a child can maintain this diet without incurring permanent damage to growth and development.
The trendy diet that adopted the same name as the anti-epilepsy diet for children is also a high-fat, low-carb weight-loss diet. The premise of the weight-loss ketogenic diet is that if the body is deprived of glucose
Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using ...
obtained from carbohydrate foods, it will produce energy from stored fat. A typical version of this keto diet for adults has about 50% of food by weight coming from fat (70% of calories). A 2020 review looked at very low carbohydrate ketogenic diet that was high in fat but low in protein. It found that it was an effective means for weight loss in those who are overweight or obese, yielding an average weight loss of 10 kg over four weeks, with maintenance of the weight loss for up to two years. However, concerns about serum sodium
Sodium ions (Na) are necessary in small amounts for some types of plants,
but sodium as a nutrient is more generally needed in larger amounts by animals, due to their use of it for generation of nerve impulses and for maintenance of electrolyte ...
levels led the authors to propose the diet only be used in "selected" people, and under strict medical supervision Supervision is used in counselling, psychotherapy, and other mental health disciplines as well as many other professions engaged in working with people. Supervision may be applied as well to practitioners in somatic disciplines for their preparatory ...
.
In 2021 the American Heart Association
The American Heart Association (AHA) is a nonprofit organization in the United States that funds cardiovascular medical research, educates consumers on healthy living and fosters appropriate cardiac care in an effort to reduce disability and death ...
issued a scientific statement on dietary guidance to improve cardiovascular health which noted that "there is insufficient evidence to support any existing popular or fad diets such as the ketogenic diet and intermittent fasting to promote heart health".
See also
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References
Further reading
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{{DEFAULTSORT:Low-Carbohydrate Diet
Diets
Fad diets