Ketogenic diet or keto diet is a nutrition management system characterized by a high-fat, adequate-protein, and low-carbohydrate diet. The primary goal of this diet is to induce ketosis or a metabolic state in which the body burns fat rather than carbohydrates for energy.
Understanding the science behind keto diet requires understanding the fact that carbohydrates, proteins, and fats are three primary macronutrients. By definition, macronutrients are energy-providing chemical substances that are essential in day-to-day functions of humans and other animals. The underlying principle behind keto diet is managing behaviors related to macronutrient consumption and the way the body use a particular macronutrient as a source of energy.
Mechanisms of ketogenic diet
The abundance of carbohydrates across different food groups means that they are readily consumed in regular and unmediated diet patterns. When consumed, the body converts the carbohydrates into glucose and insulin. Glucose is the easiest molecule the body can use as energy. This is the reason why carb-rich diet is very common. On the other hand, insulin is a hormone used for promoting the absorption of glucose from the bloodstream to the cells.
A regular medium to high-carb diet compels the body to depend on carbohydrates as the primary source of energy. Excess calories from carbohydrates and dietary fat are stored as adipose or fat tissue for use as an emergency source of energy. Fat storage is a fail-safe mechanism the body employs in case of low-food intake.
Central to the ketogenic diet is the use of fat as the primary source of energy instead of carbohydrates. Through the regular consumption of food or meals that are high in fat with moderate amounts of protein but very low in carbohydrates, ketogenic diet mimics food deprivation and compels the body to undergo a metabolic state known as ketosis.
Note that during low food intake or food deprivation, the body undergoes ketosis in which the liver converts fat into fatty acids and ketone bodies. The ketone bodies serve as the actual primary source of energy in absence of carbohydrates. The fail-safe mechanism of the body works by using fats in the adipose tissue as energy sources.
Keto diet imitates a state of food deprivation. However, instead of actually starving the body from energy source, the diet merely deprives the body from carbohydrate while exposing it to high amounts of dietary fat, thus accustoming it to ketosis. The body subsequently becomes efficient in using stored fat as an energy source.
Applications of ketogenic diet
Dr. Russell Wilder was the first to coin and introduce the term “ketogenic diet” in 1921 while working on a research that investigated the positive health implications of diet-induced ketosis at the Mayo Clinic. He was also the first to initiate trials that used keto diet as a treatment for epilepsy.
Controlling refractory or difficult-to-control epilepsy in children is the original and primary application of keto diet as a metabolic therapy. Studies revealed that an elevated level of ketone bodies in the blood lessens the frequency of epileptic seizure in pediatric patients. The exact mechanism is still unknown but some theories suggest that ketone bodies have anticonvulsant properties that suppress the excessive and rapid firing of neurons during seizures.
The effects of fasting in reducing epileptic seizure have been observed for thousands of years already. Fasting induces the body to undergo a state of ketosis. However, prolonged fasting is not recommended for children with epilepsy. Keto diet provides an alternative approach nonetheless.
Other studies have also been exploring other medical applications of ketogenic diet. The diet is essentially a metabolic therapy that addresses related problems by targeting energy production and utilization within cells. One notable application involves examining the effects of the diet in cell protection to prevent or control neurodegenerative disorders such as Parkinson’s disease and Alzheimer’s disease and psychiatric disorders such as clinical depression and autism.
Managing metabolic disorders such as diabetes mellitus and obesity is another emerging medical application of ketogenic diet. In fact, because this diet discourages the consumption of food high in carbohydrates, it has increasingly become popular as a standalone weight-loss regimen and as a component of physical fitness programs aimed at reducing body fat.
The exact underlying mechanisms explaining how the ketogenic diet induces weight loss remain unclear. There are several assumptions from studies nonetheless. Some of these studies collectively suggest that the diet induces metabolic and biological activities that require expending large amounts of calories. Other studies suggest that this diet suppresses appetites due to the food composition of ketogenic-related meals, the stimulation of appetite control hormones, and the direct appetite-suppressing effects of ketone bodies.
Different types of ketogenic diet
Several iterations to the ketogenic diet have been designed to cater to the specific needs of different individuals, especially those who are following a weight-loss program or physical fitness program. Below are the different types of ketogenic diet:
1. Standard ketogenic diet or SKD: A standard high-fat, adequate-protein, and low-carb diet comprising of 75 percent fat intake, 20 percent protein intake, and 5 percent carbs.
2. Cyclical ketogenic diet or CKD: A cyclic diet characterized by alterations between a period of standard ketogenic diet and a shorter period of high-carb diet, such as a 5-day ketogenic diet period followed by a 2-day high-carb period.
3. Targeted ketogenic diet or TKD: A modified ketogenic diet that has provisions for consuming carbohydrates for the purpose of performing physical activities, especially sports or a fitness program.
4. High-protein ketogenic diet: A modified ketogenic diet that is similar with the standard ketogenic diet but requires more protein intake, thus comprising of 60 percent fat intake, 35 percent protein intake, and 5 percent carbs.
Takeaway: The science behind ketogenic diet
What is ketogenic diet? How does ketogenic diet work? Is it effective? The science behind keto diet is fairly straightforward: It is a nutrition management system designed to force the body to enter a metabolic state that will allow it to use fats as the primary source of energy by starving it from carbohydrates.
The diet certainly has several health-related benefits or advantages. It is an established metabolic therapeutic approach for managing hard-to-control epilepsy and possibly, other diseases. A large and growing literature supports the science behind ketogenic diet. However, it is important to take note the ketogenic diet also has its own fair share of health-related and non-health-related disadvantages.
FURTHER READINGS AND REFERENCES
- Freeman, J. M., Kossoff, E. H., & Hartman, A. L. 2007. The ketogenic diet: One decade later. Pediatrics. 119(3). DOI: 10.1542/peds.2006-2447
- Kossoff, E. H. 2016. Overview: Ketogenic diets and pediatric epilepsy: An update. In ed. S. A. Masino, Ketogenic diet and metabolic therapies: Expanded roles in health and disease. Oxford: Oxford University Press
- Paoli, A. 2014. Ketogenic diet for obesity: Friend or foe? International Journal of Environmental Research and Public Health. 11(2): 2092-2107. DOI: 10.3390/ijerph110202092
- Wilder, Russel, M. 1921. The effect of ketonemia on the course of epilepsy. Mayo Clinic Bulletin. 2: 301.