Before discussing the theory and metabolic effects of the ketogenic diet, it is useful to briefly review the history of the ketogenic diet and how it has evolved. There are two primary paths (and numerous sub-paths) that the ketogenic diet has followed since its inception: treatment of epilepsy and the treatment of obesity.
Fasting
Without discussing the technical details here, it should be understood that fasting (the complete abstinence of food) and ketogenic diets are metabolically very similar. The similarities between the two metabolic states (sometimes referred to as 'starvation ketosis' and 'dietary ketosis' respectively) have in part led to the development of the ketogenic diet over the years. The ketogenic diet attempts to mimic the metabolic effects of fasting while food is being consumed.
Epilepsy (compiled from references 1-5)
The ketogenic diet has been used to treat a variety of clinical conditions, the most well known of which is childhood epilepsy. Writings as early as the middle ages discuss the use of fasting as a treatment for seizures. The early 1900's saw the use of total fasting as a treatment for seizures in children. However, fasting cannot be sustained indefinitely and only controls seizures as long as the fast is continued.
Due to the problems with extended fasting, early nutrition researchers looked for a way to mimic starvation ketosis, while allowing food consumption. Research determined that a diet high in fat, low in carbohydrate and providing the minimal protein needed to sustain growth could maintain starvation ketosis for long periods of time. This led to development of the original ketogenic diet for epilepsy in 1921 by Dr. Wilder. Dr. Wilder's ketogenic diet controlled pediatric epilepsy in many cases where drugs and other treatments had failed. The ketogenic diet as developed by Dr. Wilder is essentially identical to the diet being used in 1998 to treat childhood epilepsy.
The ketogenic diet fell into obscurity during the 30's, 40's and 50's as new epilepsy drugs were discovered. The difficulty in administering the diet, especially in the face of easily prescribed drugs, caused it to all but disappear during this time. A few modified ketogenic diets, such as the Medium Chain Triglyceride (MCT) diet, which provided greater food variability were tried but they too fell into obscurity. In 1994, the ketogenic diet as a treatment for epilepsy was essentially 'rediscovered' in the story of Charlie, a 2-year-old with seizures that could not be controlled with medications or other treatment, including brain surgery. Charlie's father found reference to the ketogenic diet in the literature and decided to seek more information, ending up at Johns Hopkins medical center.
Charlie's seizures were completely controlled as long as he was on the diet. The amazing success of the ketogenic diet where other treatments had failed led Charlie's father to create the Charlie Foundation, which has produced several videos, published the book "The Epilepsy Diet Treatment: An introduction to the ketogenic diet", and has sponsored conferences to train physicians and dietitians to implement the diet. Although the exact mechanisms of how the ketogenic diet works to control epilepsy are still unknown , the diet continues to gain acceptance as an alternative to drug therapy.
Other clinical conditions
Epilepsy is arguably the medical condition that has been treated the most with ketogenic diets (1-3). However, preliminary evidence suggests that the ketogenic diet may have other clinical uses including respiratory failure (6), certain types of pediatric cancer (7-10), and possibly head trauma (11) . Interested readers can examine the studies cited, as this book focuses primarily on the use of the ketogenic diet for fat loss.
Obesity
Ketogenic diets have been used for weight loss for at least a century, making occasional appearances into the dieting mainstream. Complete starvation was studied frequently including the seminal research of Hill, who fasted a subject for 60 days to examine the effects, which was summarized by Cahill (12). The effects of starvation made it initially attractive to treat morbid obesity as rapid weight/fat loss would occur. Other characteristics attributed to ketosis, such as appetite suppression and a sense of well being, made fasting even more attractive for weight loss. Extremely obese subjects have been fasted for periods up to one year given nothing more than water, vitamins and minerals.
The major problem with complete starvation is a large loss of body protein, primarily from muscle tissue. Although protein losses decrease rapidly as starvation continues, up to one half of the total weight lost during a complete fast is muscle and water, a ratio which is unacceptable.
In the early 70's, an alternative approach to starvation was developed, termed the Protein Sparing Modified Fast (PSMF). The PSMF provided high quality protein at levels that would prevent most of the muscle loss without disrupting the purported 'beneficial' effects of starvation ketosis which included appetite suppression and an almost total reliance on bodyfat and ketones to fuel the body. It is still used to treat severe obesity but must be medically supervised (13).
At this time, other researchers were suggesting 'low-carbohydrate' diets as a treatment for obesity based on the simple fact that individuals tended to eat less calories (and hence lose weight/fat) when carbohydrates were restricted to 50 grams per day or less (14,15). There was much debate as to whether ketogenic diets caused weight loss through some peculiarity of metabolism, as suggested by early studies, or simply because people ate less.
The largest increase in public awareness of the ketogenic diet as a fat loss diet was due to "Dr. Atkins Diet Revolution" in the early 1970's (16). With millions of copies sold, it generated extreme interest, both good and bad, in the ketogenic diet. Contrary to the semi-starvation and very low calorie ketogenic diets which had come before it, Dr. Atkins suggested a diet limited only in carbohydrates but with unlimited protein and fat. He promoted it as a lifetime diet which would provide weight loss quickly, easily and without hunger, all while allowing dieters to eat as much as they liked of protein and fat. He offered just enough research to make a convincing argument, but much of the research he cited suffered from methodological flaws.
For a variety of reasons, most likely related to the unsupported (and unsupportable) claims Atkins made, his diet was openly criticized by the American Medical Association and the ketogenic diet fell back into obscurity (17). Additionally, several deaths occurring in dieters following "The Last Chance Diet" - a 300 calorie-per-day liquid protein diet, which bears a superficial resemblance to the PSMF - caused more outcry against ketogenic diets.
From that time, the ketogenic diet (known by this time as the Atkins diet) all but disappeared from the mainstream of American dieting consciousness as a high carbohydrate, lowfat diet became the norm for health, exercise performance and fat loss.
Recently there has been a resurgence in low carbohydrate diets including "Dr. Atkins New Diet Revolution" (18) and "Protein Power" by the Eades (19) but these diets are aimed primarily at the typical American dieter, not athletes.
Ketogenic diets and bodybuilders/athletes
Low carbohydrate diets were used quite often in the early years of bodybuilding (the fish and water diet). As with general fat loss, the use of low carbohydrate, ketogenic diets by athletes fell into disfavor as the emphasis shifted to carbohydrate based diets.
As ketogenic diets have reentered the diet arena in the 1990's, modified ketogenic diets have been introduced for athletes, primarily bodybuilders. These include so-called cyclical ketogenic diets (CKD's) such as "The Anabolic Diet" (20) and "Bodyopus" (21).
During the 1980's, Michael Zumpano and Daniel Duchaine introduced two of the earliest CKD's: 'The Rebound Diet' for muscle gain, and then a modified version called 'The Ultimate Diet' for fat loss. Neither gained much acceptance in the bodybuilding subculture. This was most likely due to difficulty in implementing the diets and the fact that a diet high in fat went against everything nutritionists advocated.
In the early 1990's, Dr. Mauro DiPasquale, a renowned expert on drug use in sports, introduced "The Anabolic Diet" (AD). This diet alternated periods of 5-6 days of low carbohydrate, moderate protein, moderate/high fat eating with periods of 1-2 days of unlimited carbohydrate consumption (20). The major premise of the Anabolic Diet was that the lowcarb week would cause a 'metabolic shift' to occur, forcing the body to use fat for fuel. The high carb consumption on the weekends would refill muscle carbohydrate stores and cause growth. The carb-loading phase was necessary as ketogenic diets can not sustain high intensity exercise such as weight training.
DiPasquale argued that his diet was both anti-catabolic (preventing muscle breakdown) as well as overtly anabolic (muscle building). His book suffered from a lack of appropriate references (using animal studies when human studies were available) and drawing incorrect conclusions. As well, his book left bodybuilders with more questions than it provided answers.
A few years later, bodybuilding expert Dan Duchaine released the book "Underground Bodyopus: Militant Weight Loss and Recomposition" (21). Bodyopus addressed numerous topics related to fat loss, presenting three different diets. This included his approach to the CKD, which he called BODYOPUS. BODYOPUS was far more detailed than the Anabolic Diet, giving specific food recommendations in terms of both quality and quantity. As well, it gave basic workout recommendations and went into more detail regarding the physiology of the diet.
However, "Bodyopus" left many questions unanswered as evidenced by the numerous questions appearing in magazines and on the internet. While Duchaine's ideas were accepted to a limited degree by the bodybuilding subculture, the lack of scientific references led health professionals, who still thought of ketogenic diets as dangerous and unhealthy, to question the diet's credibility.
A question
Somewhat difficult to understand is why ketogenic diets have been readily accepted as medical treatment for certain conditions but are so equally decried when mentioned for fat loss. Most of the criticisms of ketogenic diets for fat loss revolve around the purported negative health effects (i.e. kidney damage) or misconceptions about ketogenic metabolism (i.e. ketones are made out of protein).
This begs the question of why a diet presumed so dangerous for fat loss is being used clinically without problem. Pediatric epilepsy patients are routinely kept in deep ketosis for periods up to 3 years, and occasionally longer, with few ill effects (3,5). Yet the mention of a brief stint on a ketogenic diet for fat loss and many people will comment about kidney and liver damage, ketoacidosis, muscle loss, etc. If these side effects occurred due to a ketogenic diet, we would expect to see them in epileptic children.
It's arguable that possible negative effects of a ketogenic diet are more than outweighed by the beneficial effects of treating a disease or that children adapt to a ketogenic diet differently than adults. Even then, most of the side effects attributed to ketogenic diets for fat loss are not seen when the diet is used clinically. The side effects in epileptic children are few in number and easily treated, as addressed in chapter 7.
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