What is the Ketogenic Diet?
A ketogenic diet consists of a diet that is composed of primarily of fat and protein, with very little carbohydrates. There are varying levels of ketogenic dieting with a typical diet consisting of daily carbohydrate intake around 5%, protein intake around 20%, and the remaining 75% intake consisting of fat.
Glucose vs. Fat as Energy
Your body primarily is fueled by glucose and inhibiting carbohydrates means that your body cannot rely on glucose as an effective energy source.
So, your body will rely on dietary ketosis instead of glucose metabolism as a resource for fuel. Ketone production increases and glucose production slows.
When the body is lacking carbohydrates, the mobilization of fatty acids from adipose tissue speeds up and the liver converts acetyl CoA into ketone bodies acetoacetate and 3-hydroxybutyrate. Since the liver lacks the mitochondrial enzymes to utilize the ketone bodies, they transfer to the extra hepatic tissues like the brain,1 thus replacing the need for glucose (carbs) as energy and allowing for ketone bodies to burn fat as energy instead.
Inducing starvation or a diet in low carbohydrates encourages ketone production. When an otherwise healthy individual consumes a diet consisting of mostly fat and protein and limited carbohydrates, they will tend to lose more body fat quickly and maintain lean body mass.1
Short Term Effects of Ketogenic Diet and Weight Loss
According to a meta-analysis of controlled random studies by Nordmann, Nordmann, Briel, et.al, the short-term effect of a ketogenic diet in an otherwise healthy individual supports the idea that the individual will lose more body fat and increase their lean body mass in a six-month period, however, when this length was extended to one year, there was no longer a noticeable effect,2 meaning that weight loss with this diet was not sustainable.
Long Term Effects Questionable
In another study published by the American Physiological Society published in 2014, mice that sustain a ketogenic diet long-term (over one year) have a higher likelihood of dyslipidemia and increased inflammation as well as glucose intolerance and insulin dependency, 3 further suggesting that a long-term ketogenic diet is not healthy and should be further evaluated with your physician.
Resistance Training and Building Muscle Mass
As suggested in the control trial conducted by Vargas, S., Romance R., Pedro J., et. al, there is an increased impact on weight loss when resistance training is incorporated into a ketogenic diet however would not be suggested for an individual looking to build more muscle mass.4
Summary
Several studies support1,2,3,4 a short term benefit for a faster weight loss prediction with the ketogenic diet, however, there is zero evidence that supports this method long-term and many suggestions that long term use of ketogenic diet could be detrimental to an individual’s overall health with potential negative impacts on LDL-C, glucose dependence, and insulin resistance, regardless of potential favorable outcome to HDL-C and triglyceride levels2
Other Considerations
A ketogenic diet has been proven to be very beneficial to specific groups of people with underlying conditions including epilepsy and diabetes. As with any change to your diet or lifestyle, be sure to speak with your health care practitioner regarding your all of your options and what is best for you, individually.
1. Manninen, A. Metabolic Effects of the Very-Low-Carbohydrate Diets: Misunderstood “Villians” if Human Metabolism. J. Int Soc Sports Nutr. 2004. Doi: 10.1186/1550-2783-1-2-7
2. Nordmann AJ, Nordmann A, Briel M, et al. Effects of Low-Carbohydrate vs Low-Fat Diets on Weight Loss and Cardiovascular Risk Factors- a Meta-analysis of Randomized Controlled Trials. Arch Intern Med.2006;166(3):285–293. doi:10.1001/archinte.166.3.285
3. Vargas, S., Romance, R., Pedro, J. et. al. Efficacy of ketogenic diet on body composition during resistance training in trained men: a randomized controlled trial. J Inc. Soc Sports Nutrition. 2018. Doi: 10.1186/s12970-018-0236-9
4. Dashti, H., Thazhumpal, M., Husseinm ,T, et. al, Long-term effects of a ketogenic diet in obese patients .Exp Clin Cariodol. 2004. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2716748/ . Accessed October 6, 2018.
5. Ellenbroek, J., Djick, L, Tons, H., et. al. Long-term ketogenic diet causes glucose intolerance and reduced β- and α-cell mass but no weight loss in mice. American Physiological Society. 01 March 2014. Doi: https://doi.org/10.1152/ajpendo.00453.2013