The ketogenic diet, or “keto” for short, was developed in the 1920’s and used initially as treatment for epileptic patients. Of existing low-carb, high-fat diets (e.g., Atkins, Zone, Mediterranean, and South Beach), keto is the most restrictive on carbohydrates. A ketogenic diet may consist of just 20-30 grams of carbohydrates a day, which is equivalent to about the number of carbs in one apple. In order to follow this low carbohydrate standard, the ketogenic dieter typically avoids starchy vegetables, dairy products, grains, legumes, and fruit; alcohol is also not permitted. Not only does the ketogenic diet severely restrict carbohydrates, but it also limits protein intake, requiring the dieter to obtain more calories from fat.
The ketogenic dieter obtains at least 70 percent of daily calories from fat, 5 to 10 percent from carbohydrates, and the remaining up to 25 percent from protein. Interestingly, these proportions sharply contrast against the Institute of Medicine’s recommendation to obtain 20 to 35 percent of daily calories from fat, 45 to 65 percent from carbohydrates, and 10 to 35 percent from protein.
Some notable pros of keto are its focus on foods one is allowed to eat rather than calorie counting; reducing the hunger-stimulating hormone, ghrelin; and decreasing the risk of heart disease. In contrast, major cons of this diet are its severe limitation on one’s food and beverage options, risk of fiber and other nutrient deficiency, and not being safe for women who are pregnant or breast-feeding.
How It Works
The immediate biological goal of keto is to promote ketosis, a state in which the body releases and uses ketones as a fuel source in place of glucose. Ketones are a more efficient source of energy for the brain than glucose. In fact, ketosis is associated with a higher number of brain mitochondria, which may help neurons overcome disease states involving metabolic challenges in the cell. The differential and more efficient metabolism of ketones, as compared to glucose, may help explain the many neurological benefits of the ketogenic diet.
Research suggests that keto may ameliorate symptoms of various neurological conditions including Alzheimer’s disease, Parkinson’s disease, and epilepsy (particularly for children and individuals whose epilepsy is resistant to pharmacotherapy). For instance, one meta-analysis of studies on pediatric epileptic patients showed that adherers of keto were over 2 times more likely to have seen at least a 50% reduction in seizures compared to those who dropped out of the ketogenic diet. Further, 24% and 52% of patients on the ketogenic diet experienced complete or at least 90% seizure reduction, respectively. Research reveals that the ketogenic diet may also promote recovery from brain injuries.
In addition to boasting neurological benefits, the ketogenic diet has also been shown to promote weight loss and improve heart health. The fact that this high-fat diet triggers weight loss provides an interesting challenge to the once common belief that consuming too much fat causes weight gain. Research also demonstrates that individuals on the ketogenic diet experience reductions in various biomarkers of heart disease such as BMI, blood glucose, total cholesterol, LDL (“bad”) cholesterol, and triglycerides. Additionally, the ketogenic diet’s limitation on protein may improve insulin sensitivity, which could decrease one’s risk of type 2 diabetes.
It may be possible to experience the benefits of a low-carb diet without going to the extreme of keto. In a study comparing low carbohydrate, non-ketogenic dieters to low carbohydrate, ketogenic dieters, Johnston et al. (2006) found that the two diets were equally effective in decreasing body mass and insulin resistance. However, the low carbohydrate, ketogenic group reported feeling less vigor than the low carbohydrate, non-ketogenic group. These findings indicate that the health benefits of following a low carbohydrate diet may be realized without necessarily going to the extreme of self-induced ketosis. Further, adherence to a low carbohydrate, non-ketogenic diet may be easier and result in higher energy levels than going fully keto.
In sum, the ketogenic diet boasts significant benefits such as symptom amelioration for a number of neurological conditions, weight loss, and decreased risk of heart disease. However, keto is not an easy diet to follow and could reduce feelings of vigor compared to other low carbohydrate diets. While keto is overall a great diet, it certainly isn’t for everyone.
Dashti, H. M., Mathew, T. C., Hussein, T., Asfar, S. K., Behbahani, A., Khoursheed, M. A., . . . Al-Zaid, N. S. (2004). Long-term effects of a ketogenic diet in obese patients. Experimental & Clinical Cardiology, 9(3), 200-205.
Dashti, H. M., Mathew, T. C., Khadada, M., Al-Mousawi, M., Talib, H., Asfar, S. K., . . . Al-Zaid, N. S. (2007). Beneficial effects of ketogenic diet in obese diabetic subjects. Molecular and Cellular Biochemistry, 302(1-2), 249-256.
Henderson, C. B., Filloux, F. M., Alder, S. C., Lyon, J. L., & Caplin, D. A. (2006). Efficacy of the ketogenic diet as a treatment option for epilepsy: meta-analysis. Journal of Child Neurology, 21(3), 193-198.
Johnston, C. S., Tjonn, S. L., Swan, P. D., White, A., Hutchins-Wiese, H. L., & Sears, B. (2006). Ketogenic low-carbohydrate diets have no metabolic advantage over nonketogenic low-carbohydrate diets. The American Journal of Clinical Nutrition, 83(5), 1055-1061.
Smith, G., Yoshino, J., Kelly, S., Reeds, D. N., Okunade, A., Patterson, B. W., . . . Mittendorfer, B. (2016). High-protein intake during weight loss therapy eliminates the weight-loss-induced improvement in insulin action in obese postmenopausal women. Cell Reports, 17(3), 849-861.
Veech, R. L. (2004). The therapeutic implications of ketone bodies: the effects of ketone bodies in pathological conditions: ketosis, ketogenic diet, redox states, insulin resistance, and mitochondrial metabolism. Prostaglandins, Leukotrienes and Essential Fatty Acids, 70, 309-319.