All About The Ketogenic Diet
The ketogenic diet (KD) is a way of eating high in fat, moderate in protein, and low in carbohydrates. This diet has gained traction in recent years due to its supposed effects on weight loss. Many self-proclaimed nutritionists and health coaches promote the ketogenic diet as a top-tier weight loss strategy. In this article, we will discuss whether the ketogenic diet is simply a fad or if it is a tool that can be used to promote overall health.
Before diving into the pros and cons of the KD, it is essential to discuss its several variations. These include the standard ketogenic diet (SKD), the targeted keto diet (TKD), the high protein keto diet (HPKD), and the cyclical keto diet (CKD) (Upton, 2022.) The SKD has a macronutrient distribution of 70% fat, 20% protein, and 10% carbohydrates. It is typically used for patients with epilepsy. The CKD has a similar macronutrient distribution five days per week; however, there are two “off days” where carbohydrates make up 70% of total calories. The TKD has fewer calories from fat and more from carbohydrates and protein. In this case, 65-70% of calories are from fat, 20% are from protein, and 10-15% are from carbohydrates. The TKD is typically used by active individuals or athletes who want more carbohydrates and flexibility in their diets (Upton, 2022.)
Lastly, the HPKD has a macronutrient breakdown of 60% fat, 35% protein, and 5% carbohydrates. Individuals who follow this diet consume roughly 120 or more grams of protein per day. Although carbohydrates are less than 5% of total calories consumed, protein can be converted to glucose via gluconeogenesis. Many people on this diet do not enter a state of ketosis (Upton, 2022.) The benefits and pitfalls of the ketogenic diet vary based on which variation is implemented.
Currently, the ketogenic diet is most well-known by the public as a weight loss strategy, but is it more efficient than other diets? A randomized control study by Moreno et al. published in 2014 is used by many pro-ketogenic dieters to show its effectiveness over other methods. The study showed that in 12 months, obese patients on a ketogenic diet lost significantly more weight than those on a standard low-calorie diet (Moreno, 2014). The patients on the standard low-calorie diet were given 1,400-1,800 calories per day with a macronutrient distribution within the AMDRs. Conversely, the very low-calorie ketogenic patients followed a three-stage diet. The first stage, the active stage, had a calorie range of 600-800 per day.
Even though calories were set low, there was an emphasis on keeping protein high to facilitate rapid weight loss. The second stage allowed patients to gradually reintroduce other foods and increase calories from 800 to 1500 per day. Lastly, the maintenance stage allowed patients to increase calories to 1500-2250 and follow a more balanced diet. The results of this study showed that the VLCK group lost almost double the weight as the LC group and could maintain the weight loss a year later (Moreno, 2014.)
While the VLCK group did lose a substantial amount of weight, most of the results can be attributed to the calorie discrepancy between the two diets. The standard diet group consistently ate 1400-1800 calories per day, whereas the VLCK group had calories as low as 600 per day. Additionally, the active stage of the VLCK was low in both carbohydrates and fat. The rapid weight loss seen at the beginning of the 12-month study was not due to the composition of the diet but rather the drastic reduction in calories. This study does not compare a ketogenic diet and another healthful diet of the same caloric value; therefore, it should not be used to draw conclusions about the effects of a ketogenic diet on weight loss.
A systematic review was published during the same year that excluded studies with a large discrepancy in energy intake. The review analyzed 19 randomized control trials and included overweight or obese subjects with or without diabetes. When comparing all 19 RCTs, the authors of the review found no significant changes in weight loss in those on a ketogenic diet compared with those on a balanced diet of the same caloric value (https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0100652#s3.)
According to the study, weight loss results from calorie reduction rather than macronutrient distribution. A ketogenic diet is a valuable tool in weight reduction for overweight or obese patients; however, a more balanced approach is just as effective and allows for more diversity in the diet. Although the ketogenic diet is not superior for weight loss, it offers metabolic changes that can benefit many individuals. According to a meta-analysis published in 2020, the ketogenic diet can be used as an effective therapy for patients with type II diabetes mellitus. Researchers found that reducing carbohydrates while emphasizing protein and fat can help to control fasting blood glucose, decrease hemoglobin A1c values, and improve lipid metabolism (Yuan, 2020.)
Without carbohydrates, the body uses fat and ketones as fuel. Patients with diabetes must control their carbohydrate intake because they either have insulin resistance or their body does not make enough insulin to facilitate glucose uptake into the cells. When on a ketogenic diet, patients with diabetes tend to have lower blood sugar levels because carbohydrates are typically restricted to 10-50 grams per day. Fat does not significantly impact blood sugar levels; therefore, having it be the central macronutrient of the diet can improve blood sugar control.
In addition to being a helpful tool for patients with diabetes, the ketogenic diet is often used as a treatment for children with epilepsy. The CKD has been used in children with epilepsy who are not responsive to medications since the 1920s (Wheless, 2008.) For some patients, the KD can be a treatment that reduces seizure frequency and increases quality of life. Ketones are produced when carbohydrates are low, and fat intake is high. They are used by the brain as an alternative energy source and have an anti-epileptic effect, reducing seizures. The exact mechanism has yet to be known. Researchers hypothesize that it may impact neurotransmitters, ion channels, oxidative stress, the microbiome, or neuroinflammation. Ketosis is not a guaranteed treatment for childhood epilepsy; however, the KD can reduce seizures by greater than 50% in some patients (Wells, 2020).
Another beneficial use for the ketogenic diet is as an adjuvant treatment for cancer therapy. Although more studies need to be done, there is evidence to suggest that the KD has antitumor effects on certain types of cancer. According to Jemal et al., the KD may be an addition to breast cancer treatment. Again, the exact mechanisms are not entirely understood; however, researchers believe it may be partly due to the reduced reliance on the glucose/insulin axis (Jemal, 2021.) Ketogenic diets may also suppress tumor growth by restoring the inflammatory and hormonal environment of the host (Jemal, 2021.)
In addition to breast cancer, the KD should be considered as an alternative treatment for patients with malignant brain cancer, specifically glioblastoma. A calorie-restricted version of the KD called KetoCal has been shown to significantly decrease the intracerebral growth of tumors (Zhou, 2007). Glucose is necessary for rapid tumor growth; restricting carbohydrate and total calorie intake decreases the primary substrate needed by cancer cells and thus slows their progression. Other cancers that a ketogenic diet may suppress include liver, prostate, and stomach (WebMD 2022.)
In conclusion, while the ketogenic diet is often misused by people desiring weight loss, it is a useful metabolic tool for Type II Diabetes Mellitus, childhood epilepsy, and certain cancers. The ketogenic diet should not be used as a first-line method for weight loss considering the overwhelming amount of evidence supporting a more balanced approach. Long term, the ketogenic diet may negatively impact the gut microbiome, lipid values and disrupt hormonal balance in women. Dietitians should keep the ketogenic diet as a tool to be used with specific patients rather than simply writing it off as a useless fad diet.