What's the deal with the Keto diet?

What does the research say?

Weight loss - A ketogenic diet has become popular as a quick way to lose weight but there are few studies that have evaluated its long term safety and effectiveness. Most of the short term weight loss is due to water loss from decreased glycogen (carbohydrates) stores and not from the effect of increased metabolism and fat loss.

Appetite - Increased ketone bodies as a result of a ketogenic diet decrease the feeling of hunger and lead to a loss of appetite which contributes to the short-term weight loss.

Chronic disease - As per other weight loss diets, the improved metabolic profile for type 2 diabetes and cardiovascular disease is a direct result of the weight loss rather than from the ketogenic diet itself.

Performance - A ketogenic diet does allow the body to burn fat more efficiently during low or moderate intensity exercise. On the other hand, carbohydrates are important because they provide a key fuel for the brain and central nervous system and can support different intensity levels of exercise. At the highest level of exercise, carbohydrates offer advantages over fats as an energy source, since they provide more energy to the body and can increase your exercise capacity.

Side effects - Due to the restrictive, high fat/low fibre make-up of the ketogenic diet, it may result in side effects such as:

1. constipation, skin rash and muscle cramps due to nutritional deficiencies
2. diarrhea and impaired lipid levels due to high fat intake
3. general weakness and headache from the associated metabolic acidosis.

References:

1. Burke, L.M. (2015). Re-Examining High-Fat Diets for Sports Performance: Did we call the "Nail in the Coffin" too soon? Sports Medicine, 45(Suppl 1), S33-S49.
2. Chang, C.K., Borer, K., & Lin, P.J. (2017). Low-Carbohydrate-High-Fat Diet: Can it Help Exercise Performance? Journal of Human Kinetics, 12(56), 81-92.
3. Johnston, B.C., Kanters, S., Bandayrel, K., Wu, P., Naji, F., Siemieniuk, R.A., ... Mills, E.J. (2014). Comparison of weight loss among named diet programs in overweight and obese adults: a metaanalysis. Journal of the American Medical Association, 312(9), 923-33.
4. Naude, C.E., Schoonees, A., Senekal, M., Young, T., Garner, P. & Volmink, J. (2014). Low carbohydrate versus isoenergetic balanced diets for reducing weight and cardiovascular risk: a systematic
review and meta-analysis. PloS ONE, 9(7).
5. Institute of Medicine (IOM). (2002). Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein and Amino Acids, Washington. National Academies Press.
6. Scott, J.M., & Deuster, P.A. (2017). Ketones and Human Performance. Journal of Special Operations Medicine, 7(2),112-116.
7. Volek, J.S., Noakes, T., & Phinney, S.D. (2015). Rethinking Fat as a Fuel for Endurance Exercise. European Journal of Sport Science,15(1), 13–20.