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. as of 2018, research has paid insufficient attention to the potential adverse effects of carbohydrate restricted dieting, particularly for micronutrient sufficiency, bone health and cancer risk. one low-quality meta-analysis reported that adverse effects could include "constipation, headache, halitosis, muscle cramps and general weakness". in a comprehensive systematic review of 2018, churuangsuk and colleagues reported that other case reports give rise to concerns of other potential risks of low-carbohydrate dieting including hyperosmolar coma, wernicke's encephalopathy, optic neuropathy from thiamine deficiency, acute coronary syndrome and anxiety disorder. significantly restricting the proportion of carbohydrate in diet risks causing malnutrition, and can make it difficult to get enough dietary fiber 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 a low-carbohydrate diet restricts the amount of carbohydrate-rich foods – such as bread – in the diet. first descriptions in 1797, john rollo reported on the results of treating two diabetic 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, butter, milk, sugar, beer, and potatoes. his booklet was widely read, so much so that some people used the term "banting" for the activity now called "dieting". 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, apollinaire bouchardat and frederick william pavy. arnaldo cantani isolated his diabetic patients in locked rooms and prescribed them an exclusive animal-based diet. in the early 1900s frederick madison allen 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.: 176–177 this diet was often administered in a hospital in order to better ensure compliance and safety.: 179 modern low-carbohydrate diets further information: atkins diet 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 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 levels – with fast-digesting simple carbohydrates causing a sharper increase and slower-digesting complex carbohydrates, such as whole grains, 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 and restaurant chains 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 in 2002. ketogenic diet for the epilepsy treatment, see ketogenic diet. the original ketogenic diet is a high-fat, low-carbohydrate diet developed in the 1920s and used to treat drug-resistant childhood epilepsy. the fad diet that adopted the same name is also a high-fat, low-carb diet, but proclaims to induce weight loss. the premise of the weight-loss ketogenic diet is that if the body is deprived of glucose 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 a 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 levels led the authors to propose the diet only be used in "selected" people, and under strict medical supervision. in 2021 the american heart association 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".