Episode 1. Ketogenic diet: History and Current Practices
Ketogenic diet and its history
A ketogenic diet (KD) is a high-fat, adequate-protein, low-carbohydrate diet. It was started in 1922 by Hugh Conklin to help children with epilepsy (Freeman, 2013) but fell out of favor as epileptic medications became available and effective. Since then, the use of KD as treatment for epilepsy decreased dramatically, and PubMed listed only two to eight publications per year from 1970 to 2000.
During the last few decades, the diet was brought to research again to treat refractory epilepsy and a variety of other conditions (Walczyk and Wick, 2017). Since 1995, the number of research publications related to KD increased exponentially along with its public popularity. KD rose to fame when the American audience viewed and NBC Dateline special on a diet on October 26, 1994, featuring Meryl Streep. They told the dramatic and heart-touching story of Jim Abrahams and his son, Charlie, who received successful treatment for an intractable seizure disorder with the John Hopkins Hospital's version of the diet. At the end of the television show, viewers were give a toll-free number to call and obtain information about KD. In the same year, Jim created the Charlie Foundation to Help Cure Pediatric Epilepsy, in which he quickly sold thousands of copies of KD book. The foundation also funded DVD productions of the diet and offered physicians a free copy. But, few welcome the work due to its lack of scientific supports.
In 1997, Jim directed and created a TV-movie, "First Do No Harm", also featuring Streep which brought a bigger second wave promotion on the diet. From then, everything is history. The attention led to patients who voluntarily participate in clinical studies by John Hopkins Hospital as well as renewed scientific interest worldwide (Freeman, 2013; Wheless, 1995). Today's KD has been studied for a variety of conditions other than pediatric epilepsy (Freeman et al., 2007). The use of the diet is among the most popular reason for the general public. However, it is unclear how the public perception of the KD shifted from epilepsy treatment to weight loss.
How KD looks like?
Some known modifications or alternatives to the classical KD exist, based on long-chain triglycerides (LCT) diet, medium-chain triglyceride (MCT) diet, Radcliff (modified MCT-LCT diet), modified Atkins diet, and low glycemic-index diet (Freeman et al., 2007). Among these modifications, the specific nutrition composition might vary, but the typical ratio of fats to carbohydrates and protein (in grams) is 3:1 or 4:1. Lower ratios are used successfully in other parts of the world, such as Asia, where rice is a major dietary staple (Kossoff and McGrogan, 2005; Hartman and Vining, 2007).Â
In practice, the diet allows only less than 5% daily energy requirement as carbohydrate, or between 20-50 g a day. This would practically mean eliminating most grains, fruit, starchy vegetables, legumes, and sweets. This low amount of carbs is easily reached by eating a medium banana or apple (around 27 g carbs) or drinking a glass of milk and a glass of beer (25 g carbs). Table 1 shows the example of how the menu of KD diet looks like for one day in the US.
As food takes an important part of culture, it is not possible to talk about experiences with the KD without talking about how the meal composition adjusted for different geographic region. The representation of KD meals from different countries (including the ratios and calories based on best estimates) is provided in Figure 1.
Despite the freedom to ingest as much butter and bacon as desired, many could still find this calorie intake restriction too limiting and unpalatable as it is important to remember that a strict keto diet includes no more than 10% of the total daily calorie intake in the form of carbohydrates, 20% as proteins and the remaining as fat. Figure 2 gives an overview of how much carbohydrates contained in different foods.
In the next episode, we will discuss further on how KD actually helps us to lose weight from its mechanism of action perspective and how it physiologically affect our body.
S.A.D Team
Reference
Freeman J.M. Epilepsy's big fat answer. Cerebrum: the Dana forum on brain science: Dana foundation. 2013
Walczyk T., Wick, J.Y. The ketogenic diet: making a comeback. The Consultant Pharmacist®. 2017; 32(7): 388 -- 96.
Wheless, J.W. The ketogenic diet: fact or finction. Sage Publications Sage CA: Thousand Oaks, CA. 1995.
Freeman, J.M., Kossoff, E.H., Harman, A.L. The ketogenic diet: one decade later. Pediatrics. 2007; 119(3): 535 -- 43.
Kossoff, E. H., and McGrogan, J. R. Worldwide Use of the Ketogenic Diet. Epilepsia. 2005. 46: 280 -- 289. doi:10.1111/j.0013-9580.2005.42704.x.
Hartman, A. L., and Vining, E. P. G. Clinical Aspects of the Ketogenic Diet. Epilepsia. 2007. 48: 31 -- 42.
O’Neill, B., and Raggi, P. The ketogenic diet: Pros and cons. Atherosclerosis. 2020. 292: 119 -- 126. doi:10.1016/j.atherosclerosis.2019.11.021.