The Atkins diet, officially called the Atkins Nutritional Approach, is a low-carbohydrate diet created by Dr Robert Atkins from a diet he read in the Journal of the American Medical Association and used to resolve his own overweight condition. He later popularized the Atkins diet in a series of books, starting with Dr. Atkins' Diet Revolution in 1972. In his revised book, Dr. Atkins' New Diet Revolution, he modified or changed some of but remained faithful to the original concepts.

Atkins franchise, a business formed to provide products to those individuals on the diet, was highly successful because of the popularity of the diet, and is considered the driving entity of the larger "low-carb craze" [2] during the early millennium. However its success dwindled and Atkins Nutritionals of Ronkonkoma, New York, the company founded by Dr. Atkins in 1989, filed for Chapter 11 bankruptcy in January 2005, two years after his death. The company re-emerged in January 2006, and the Atkins logo is still highly visible through licensed-proprietary branding for food products and related merchandise.

Contents 1 Nature of the diet 2 Ketogenic Diet 3 Main Risks/ Benefits 3.1 Cholesterol 3.2 Methylglyoxal 3.3 Other 4 The Four Phases 4.1 Induction 4.2 Ongoing weight loss 4.3 Pre-maintenance 4.4 Lifetime maintenance 5 Popularity 6 Scientific studies 7 Controversies 8 Misconceptions about the diet 9 Atkins Nutritionals 10 Books 11 See also 12 References 13 External links

[edit] Nature of the diet

The Atkins Diet is a departure from the previously prevailing metabolic theories. Atkins said that there are important unrecognized factors in Western eating habits leading to obesity. Primarily, he believed that the main cause of obesity is eating refined carbohydrates, particularly sugar, flour, and high-fructose corn syrups.

The Atkins Diet involves restriction of carbohydrates to more frequently switch the body's metabolism from burning glucose as fuel to burning stored body fat. This process (called ketosis) begins when insulin levels are low; in normal humans, insulin is lowest when blood glucose levels are low (mostly before eating). Caloric carbohydrates (e.g., glucose or starch (itself made of chains of glucose)) produce most of the blood sugar after meals and can be calculated to determine the insulin needs of diabetics.^[1] Because of its low digestibility, fiber provides little or no food energy and does not significantly impact glucose and insulin levels. Ketosis involves lipolysis in which some of the lipid stores in fat cells are transferred to the blood.

In his book Dr Atkins' New Diet Revolution, Dr. Atkins made the controversial argument that the low-carbohydrate diet produces a metabolic advantage in which the body burns more calories, overall, than on normal diets, and also expels some unused calories. He cited one study where he estimated this advantage to be 950 calories (4.0 MJ) a day. However, a review study published in the Lancet^[2] concluded that there was no such metabolic advantage and dieters were simply eating fewer calories because of boredom. Professor Astrup stated, "The monotony and simplicity of the diet could inhibit appetite and food intake" The Atkins Diet restricts "net carbs" (digestible carbohydrates that impact blood sugar). One effect is a tendency to decrease the onset of hunger, perhaps because of longer duration of digestion (fats and proteins take longer to digest than carbohydrates). Dr. Atkins says in Dr. Atkins' New Diet Revolution (2002) that hunger is the number one reason why low-fat diets fail. Although studies show the efficacy of the Atkins approach after one year is the same as some low-fat diets, it was easier, according to Atkins, to stay on the diet because low-fat dieters "were often hungry and always felt deprived" [p 3].

Net carbohydrates can be calculated from a food source by subtracting fiber and sugar alcohols (which are shown to have a smaller effect on blood sugar levels) from total carbohydrates. Sugar alcohols contain about two calories per gram, and the American Diabetes Association recommends that diabetics count each gram as half a gram of carbohydrate.^[3] Fructose (e.g., as found in many industrial sweeteners) has four calories per gram, although it has a very low glycemic index^[4] and does not cause insulin production, probably because ß cells have low levels of GLUT5.^[5][6]

Preferred foods in all categories are whole, unprocessed foods with a low glycemic index, although restrictions for low glycemic carbohydrates (blackrice, vegetables, etc.) are the same as those for high glycemic carbohydrates (sugar, white bread). Atkins Nutritionals, the company formed to market foods which work with the Atkins Diet, recommends that no more than 20% of calories eaten while on the diet come from saturated fat.^[7]

According to the book Atkins Diabetes Revolution, for people whose blood sugar is abnormally high or who have Type 2 diabetes mellitus, this diet decreases or eliminates the need for drugs to treat these conditions. The Atkins Blood Sugar Control Program (ABSCP) is an individualized approach to weight control and permanent management of the risk factors for diabetes and cardiovascular disease.^[8] Nevertheless, the causes of Type 2 diabetes remain obscure, and the Atkins Diet is not accepted in conventional therapy for diabetes.

[edit] Ketogenic Diet

The induction phase of the Atkins diet is a ketogenic diet. In ketogenic diets there is production of ketones that contribute to the energy production in the Krebs cycle.^[9] Ketogenic diets rely on the insulin response to blood glucose. Since, in ketogenic diets, dieters do not eat carbohydrates, there is no glucose that can trigger the insulin response. When there is no glucose-insulin response there are some hormonal changes that cause the stored fat to be used for energy. Blood glucose levels have to decrease to less than 3.58 mmol/L for growth hormone, epinephrine, and glucagon to be released to maintain energy metabolism.^[9] In the adipose cells, growth hormone and epinephrine initiate the triacylglycerol to be broken down to fatty acids. These fatty acids go to the liver and muscle where they should be oxidized and give acetyl-CoA that enters the Krebs cycle directly.^[9] However, the excess acetyl-CoA in the liver is converted to ketones (ketone bodies), that are transported to other tissues. In these tissues they are converted back into acetyl-CoA in order to enter the Krebs cycle. Glucagon is produced when blood glucose is too low, and it causes the liver to start breaking glycogen into glucose. Since the dieter does not eat any more carbohydrates, there is no glycogen in the liver to be broken down, so the liver converts fats into free fatty acids and ketone bodies, and this process is called KETOSIS. Because of this, the body is forced to use fats and ketosis as a primary fuel source, and that is why Atkins is a ketogenic diet.^[9]

[edit] Main Risks/ Benefits

The risks and benefits of the Atkins diet remain a subject of much debate. Whereas many studies have shown that the Atkins diet helps prevent cardiovascular disease, lowers the low density lipoprotein (LDL) cholesterol, and increases the amount of HDL cholesterol, other studies claim that the diet contributes to cardiovascular disease, coronary heart disease, arrhythmia, osteoporosis, and kidney stones.

[edit] Cholesterol

According to Harper (2004) in a year long study, the concentration of HDL cholesterol increased, and insulin resistance improved much more in dieters following the Atkins diet than in those following a low fat, calorie restricted diet. Harper also mentions that there had not been enough prior research to allow him to confidently say that Atkins is safe to be recommended to patients.^[10] In later studies, as Barnett et al. reported in 2009, cholesterol levels have increased in almost one third of dieters using low-carbohydrate diets, like Atkins, and since then two cardiac deaths have been reported, one due to coronary heart disease, and the other due to arrhythmia. In this study, a 51 year old, healthy, non-smoking and physically active man started practicing the Atkins diet, in order to regain his original weight. His LDL cholesterol increased drastically after just one month, but he continued to follow the diet. Two years into the diet, he began to take medicine for erectile dysfunction and after a few months was hospitalized for critical stenosis of the coronary artery. He abandoned the Atkins diet and was started on medication therapy, which resulted in his blood cholesterol and triglycerides going back to normal, and the ending of chest pain and erectile dysfunction.^[11] Here we can see that these two studies are contradictory.

[edit] Methylglyoxal

A 2005 study by Beisswenger and colleagues compared levels of the glycotoxin methylglyoxal (MG) before and after starting the Atkins diet. MG is associated with blood vessel and tissue damage, and is higher in people with poorly controlled diabetes. The study found that MG levels doubled shortly after the diet was started, noting that the MG rise was related to the presence of ketosis. A rise in acetol and acetone was found, indicating that MG was produced by oxidation. MG also arose as a by-product of triglyceride breakdown and from lipoxidation (ketosis related to fat intake).^[12]

[edit] Other

High protein diets can cause the loss of calcium and a lowering in urinary citrate levels, which may lead to osteoporosis and kidney stones (Ornish,2004). Ketone bodies are excreted in urine with cations to neutralize the charge, so the body is losing essential cation minerals such as calcium, potassium, and magnesium, which in one case led to the death of a sixteen-year-old girl. She died from ventricular fibrillation arrest two weeks after starting a high protein-low carbohydrate diet. During resuscitation attempts she had hypokalemia (lower than normal amount of potassium in the blood) and also hypocalcemia (lower than normal amount of calcium in the blood)^[13] Ornish also wrote that the Atkins diet leads to constipation in 70% of the subjects, 65% had halitosis (bad breath), 54% were experiencing headaches, and 10% reported hearing loss.^[14]

Halitosis is a serious problem for Atkins dieters. The ketone bodies produced during ketosis in the body can be smelled through the mouth, and it is a very unpleasant scent.

See also controversies.

[edit] The Four Phases

There are four phases of the Atkins diet: induction, ongoing weight loss, pre-maintenance and lifetime maintenance.

[edit] Induction

The Induction phase is the first, and most restrictive, phase of the Atkins Nutritional Approach. Two weeks are recommended for this phase. It is intended to cause the body to quickly enter a state of ketosis. Carbohydrate intake is limited to no more or less than 20 net grams per day (grams of carbohydrates minus grams of fiber, sugar alcohols, or glycerin), 12 to 15 net grams of which must come in the form of salad greens and other vegetables (broccoli, spinach, pumpkin, cauliflower, turnips, tomatoes, and asparagus, to name a few of the 54 allowable vegetables [but not legumes, such as green beans, since they are too starchy for the induction phase]). The allowed foods include a liberal amount of all meats, poultry, fish, shellfish, fowl, and eggs; up to 4 ounces (113 g) of soft or semi-soft cheese such as cheddar cheese; salad vegetables; other low carbohydrate vegetables; and butter, olive oil and vegetable oils. Drinking eight glasses of water per day is a requirement during this phase. Alcoholic beverages are not allowed during this phase.^[15] Caffeine is allowed in moderation so long as it does not cause cravings or low blood sugar. If a caffeine addiction is evident, it is best to not allow it until later phases of the diet.^[15] A daily multivitamin with minerals, except iron, is also recommended. A normal amount of food, on Induction, is around 20 grams of sugar (or net carb.), at least 100 grams of fat, and some where between 1 and 2 pounds of meat.

The Induction Phase is usually when many see the most significant weight loss — reports of losses of 5 to 10 pounds per week are not uncommon when Induction is combined with daily exercise. Many Atkins followers make use of Ketostix, small chemically reactive strips used by diabetics. These let the dieter monitor when they enter the ketosis, or fat burning, phase, but are not always accurate for non-diabetic users. Other indicators of ketosis include a metallic taste in the mouth, or bad breath.

[edit] Ongoing weight loss

The Ongoing Weight Loss (OWL) phase of Atkins consists of an increase in carbohydrate intake, but remaining at levels where weight loss occurs. The target daily carbohydrate intake increases each week by 5 net grams. A goal in OWL is to find the "Critical Carbohydrate Level for Losing" and to learn in a controlled manner how food groups in increasing glycemic levels and foods within that group affect your craving control. The OWL phase lasts until weight is within 10 pounds (4.5 kg) of the target weight. During the first week, one should add more of the induction acceptable vegetables to one's daily products. For example, 6-8 stalks of asparagus, salad, one cup of cauliflower or one half of avocado. The next week, one should follow the carbohydrate ladder that Dr Atkins created for this phase and add fresh dairy. The ladder has 9 rungs and should be added in order given. One can skip a rung if one does not intend to include that food group in one's permanent way of eating, such as the alcohol rung. The rungs are as follows:

• Induction acceptable vegetables in larger quantities
• Fresh cheese
• Nuts and seeds
• Berries
• Alcohol
• Legumes
• Other fruits
• Starchy vegetables
• Whole grains

[edit] Pre-maintenance

Carbohydrates intake is increased again this time by 10 net carbs a week from the ladder groupings, and the key goal in this phase is to find the "Critical Carbohydrate Level for Maintenance", this is the maximum number of carbohydrates you can eat each day without gaining weight. This may well be above the level of carbohydrates inducing ketosis on a testing stick. As a result, it is not necessary to maintain a positive ketosis test long term.

[edit] Lifetime maintenance

This phase is intended to carry on the habits acquired in the previous phases, and avoid the common end-of-diet mindset that can return people to their previous habits and previous weight. Whole, unprocessed food choices are emphasized, with the option to drop back to an earlier phase if you begin to gain weight.

[edit] Popularity

The Atkins Nutritional Approach gained widespread popularity in 2003 and 2004. At the height of its popularity one in eleven North-American adults were on the diet.^[16] This large following was blamed for large declines in the sales of carbohydrate-heavy foods like pasta and rice (sales were down 8.2 and 4.6 percent, respectively, in 2003^[17]). The diet's success was even blamed for a decline in Krispy Kreme sales [3]. Trying to capitalize on the "low-carb craze," many companies released special product lines that were low in carbohydrates. Coca-Cola released C2 and Pepsi-Cola created Pepsi Edge, which was scheduled to be discontinued later in 2005. Unlike the sugar-free soft drinks Diet Coke and Diet Pepsi, which had been available for decades, these new drinks used a blend of sugar and artificial sweeteners to offset the flavour of artificial sweetener. These "half-and-half" drinks declined in popularity as soft drink makers learned to use newer sweeteners to mask the flavour of aspartame (or completely replace it) in reformulated diet drinks such as Coca-Cola Zero and Pepsi ONE.

Low-carbohydrate diets and the societal changes they have caused have been a subject of interest in the news and popular media. Coverage has included among other things a one-hour documentary television special called The Low Carb Revolution on Food Network Canada, on April 25, 2004.

In 2003, Robert Atkins died from a fatal head injury sustained in a fall on ice.^[18] His death came after a battle with a heart condition, cardiomyopathy, reportedly caused by a viral infection, which had caused noticeable weight fluctuation in his final years. This combination of circumstances led to rumors and allegations that Dr. Atkins had died from complications arising from his namesake nutritional plan. However contemporary accounts from his physicians did not substantiate these rumours.^[19][20][21] Nevertheless the reputation of the nutritional plan, and the low-carbohydrate concept in general, suffered.

On July 31, 2005, the Atkins Nutritional company filed for Chapter 11 bankruptcy protection after the percentage of adults on the diet declined to two percent and sales of Atkins brand product fell steeply in the second half of 2004. The company continues to operate and the diet plan remains popular although it has never regained its former popularity.

Not long on the heels of the diet's popularity, Arrested Development released an episode called Let 'Em Eat Cake using several characters' taking of the diet as a sub-story and running joke.

[edit] Scientific studies

Because of the substantial controversy regarding the Atkins Diet and even disagreements in interpreting the results of specific studies it is difficult to objectively summarize the research in a way that reflects scientific consensus.^[22][23] Although there has been some research done throughout the twentieth century,^[24][25] most directly relevant scientific studies, both those that directly analyze the Atkins Diet and those that analyze similar diets, have occurred in the 1990s and early 2000s and, as such, are relatively new. Researchers and other experts have published articles and studies that run the gamut from promoting the safety and efficacy of the diet^[26][27] to questioning its long-term validity^[28][29] to outright condemning it as dangerous.^[30][31] Until recently a significant criticism of the Atkins Diet was that there were no studies that evaluated the effects of Atkins beyond a few months. However, studies are emerging which evaluate low-carbohydrate diets over much longer periods, controlled studies as long as two years and survey studies as long as two decades.^{[26][32][33][34]}

In addition to research on the efficacy of Atkins and other low-carbohydrate diets some research has directly addressed other areas of health affected by low-carbohydrate diets. For example, contrary to popular belief that low-carbohydrate diets damage the heart, one study found that women eating low-carbohydrate, high-fat/protein diets had the same or slightly less risk of coronary heart disease, compared to women eating high-carbohydrate, low-fat diets.^[35] Other studies have found possible benefits to individuals with diabetes,^[36] cancer,^[37][38] and epilepsy.^[39][40] Nevertheless some studies demonstrate potentially harmful effects of certain types of low-carbohydrate diets including various metabolic and emotional side-effects.^[41]

In 2009 a multi-center prospective randomized trial of 811 overweight adults compared four diets emphasizing varying ratios of fat, protein and carbohydrate.^[42] All diets were designed to create a 750 kcal deficit. Participants who completed the study lost an average of 4 kg regardless of diet composition. Most of the weight loss occurred in the first six months with some regain by 2 years. Blood pressure changes and waist circumference were also similar between groups, though the low fat diet yielded greater reduction in LDL ("bad cholesterol"). It should be noted that the lowest carbohydrate composition included in this study was 25%, which is significantly above the recommended carbohydrate level advocated by the Atkins Nutritional Approach.

[edit] Controversies

An analysis conducted by Forbes magazine found that the sample menu from the Atkins Nutritional Approach is one of the top five in the expense category of ten plans Forbes analyzed. This was due to the inclusion of recipes with some high cost ingredients such as lobster tails which were put in the book to demonstrate the variety of foods which could be consumed on the diet. The analysis showed the median average of the ten diets was approximately 50% higher, and Atkins 80% higher, than the American national average. Atkins was less expensive than Jenny Craig and more expensive than Weight Watchers.^[43]

Low-carbohydrate diets have been the subject of heated debate in medical circles for three decades. They are still controversial and only recently has any serious research supported some aspects of Atkins' claims, especially for short-term weight-loss (6 months or less). In a comparison study done by Dansinger and colleagues (2005), the goal was to compare popular diets like Atkins, Ornish, Weight Watchers, and Zone for the amount of weight lost and a heart disease risk reduction. In the study there were 247 individuals and it lasted for 1 year. All the subjects were overweight at baseline, and had an increased risk for cardiac diseases. One of the diets was assigned to each person. ^[44] The Atkins diet group ate 20g of CHO a day, with an increase to 50g a day gradually. The Zone group ate a 40-30-30 % diet of carbohydrates, fats and proteins respectively. The Weight Watchers group was to keep the “points” of their food in a determined range, based on their weight. The Ornish group ate a vegetarian diet with 10% of calories coming from fats. The weight, waist size, blood pressure, and a blood sample were taken, at the beginning, after 2 months, 6 months and 12 months. All four diets resulted in weight loss with no significant difference between the diets.^[45]

But many in the scientific community also raise serious concerns:

• Dr. Robert Eckel of the American Heart Association says that high-protein, low-carbohydrate diets put people at risk of heart disease [4]; A long term study published in the New England Journal of Medicine in 2006 found that women reduced heart disease risk by eating more protein and fat from vegetable sources.^[46]
• A 2001 scientific review conducted by Freedman et al. and published in the peer reviewed scientific journal Obesity Research concluded that low-carb dieters' initial advantage in weight loss was a result of increased water loss, and that after the initial period, low-carbohydrate diets produce similar fat loss to other diets with similar caloric intake.^[47]
• The May 2004 Annals of Internal Medicine study showed that "minor adverse effects" of diarrhea, general weakness, rashes and muscle cramps "were more frequent in the low-carbohydrate diet group".
• Concerns have been raised regarding consumption of high levels of protein in individuals with medical conditions such as kidney disease or gout.

Opponents of the diet also point out that the initial weight loss upon starting the diet is a phenomenon common with most diets, and is due to reduction in stored glycogen and related water in muscles, not fat loss. They claim that no evidence has surfaced that any diet will cause weight loss unless it reduces food energy (calories) below the maintenance level and that weight loss from the Atkins diet may be the result of less food energy being consumed by the dieter, rather than the lack of carbohydrates.^[48] They further point out that weight loss on fad diets, which typically restrict or prohibit certain foods, is often because the dieter has fewer food choices available.

[edit] Misconceptions about the diet

Many people incorrectly believe that the Atkins Diet promotes eating unlimited amounts of fatty meats and cheeses. This is a key point of clarification that Dr. Atkins addressed in the more recent revisions of his book. Although the Atkins Diet does not impose caloric restriction, or definite limits on proteins, Dr. Atkins points out in his book that this plan is "not a license to gorge." The director of research and education for Atkins Nutritionals, Collette Heimowitz, has said, "The media and opponents of Atkins often sensationalise and simplify the diet as the all-the-steak-you-can-eat diet. This has never been true."^[7]

Another common misconception arises from confusion between the Induction Phase and rest of the diet. The first two weeks of the Atkins Diet are strict, with only 20g of carbohydrates permitted per day. Atkins states that a dieter can safely stay at the Induction Phase for several months if the person has a lot of weight to lose.^[49] Induction, however, is merely a stage to get the body used to fat, and cure cravings for unacceptable foods. Gradually, carbohydrate levels are raised to slow weight loss and add more acceptable foods (berries, more dairy, nuts, etc.), though carbs are still significantly below USDA norms. Once the weight-loss goal is reached, carbohydrate levels are raised again to a state of equilibrium where no weight is lost or gained, which may or may not be below USDA norms, depending on the individual's metabolism, age, and their exercise level.

[edit] Atkins Nutritionals

Atkins Nutritionals, Inc. (ANI) was founded in 1989 by Dr. Robert Atkins to promote the diet and sell Atkins-branded products. Following his death, waning popularity of the diet and a reduction in demand for Atkins products, Atkins Nutritionals, Inc. filed for Chapter 11 bankruptcy protection on July 31, 2005 citing losses of $340 million.^[50] The company emerged from bankruptcy on January 10, 2006, introducing "a new business strategy that focuses on providing great-tasting portable foods with a unique nutrition advantage to healthy, active men and women."^[51] Although the marketing focus has changed, the products are still low-carb. It is also stated on the packages the stage of the Atkins Nutritional Approach where they may be used.

[edit] Books

• Robert C. Atkins (2004) Atkins for Life: The Complete Controlled Carb Program for Permanent Weight Loss and Good Health, 370pp, St. Martin's Press, ISBN 0-641-67892-4
• Robert C. Atkins (2001) Dr. Atkins' New Diet Revolution book, 560 pp, Avon Books; Revised ed., ISBN 0-06-001203-X, ISBN 0-09-188948-0
• Robert C. Atkins (2000) Dr. Atkins' Age-Defying Diet Revolution: A Powerful New Dietary Defense Against Aging, Saint Martin's Press, LLC, ISBN 9780312251895
• Robert C. Atkins (1999) Dr. Atkins' Vita-Nutrient Solution: Nature's Answer to Drugs, 416 pp, Fireside Books (Simon & Schuster), ISBN 0-684-84488-5.

[edit] See also

• Diet
• Dieting
• Low-carb tortilla
• Low-carbohydrate diet
• Medical research related to low-carbohydrate diets

[edit] References

[edit] External links

Wikibooks Cookbook has a recipe/module on Atkins Diet Cooking

• Official Atkins Corporate Site
• Atkins diet at the Open Directory Project
• New England Journal of Medicine: (vol 348, p 2082) A randomized trial of a low-carbohydrate diet for obesity.
• New England Journal of Medicine: (vol 359, p 229) Weight Loss with a Low-Carbohydrate, Mediterranean, or Low-Fat Diet (July 17, 2008)
• Easy Healthy Diet