The Effects of a Ketogenic Diet on Anthropometric Parameters, Metabolic Adaptation, and Physical Fitness Performance in Amateur Endurance Athletes: A Systematic Review

Moreno-Villanueva, Adrián MD; Rico-González, Markel MD; Pino-Ortega, José PhD


Strength and Conditioning Journal: April 2022 - Volume 44 - Issue 2 - p 114-124 doi: 10.1519/SSC.0000000000000647


PURPOSE:

Reviewed systematically the effects of Keto Diets (KDs) on anthropometric, metabolic, and performance parameters in amateur endurance sport athletes, highlighting the recommendations about how they should be used. This review was performed under Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. It was also performed using 2 databases - PubMed and Web of Sciences. Of the 1,485 studies initially identified, 14 were fully reviewed, and their outcome measures were extracted and analyzed.


RESULTS:

Regarding anthropometrics:

KDs (daily caloric intake of carbs @ < 5%) can lead to a reduction of body weight and percentage fat mass, with a possible impact on maintenance of fat-free mass.


Regarding the metabolic adaptations:

KDs lead to glycogen storage and fat mobilization when using daily caloric intake of carbs was less than 8%.


Regarding endurance performance parameters:

No positive or negative physical fitness and conditioning effects were found when using KDs.


IN PLAIN ENGLISH:

Even though KDs could be used to induce anthropometric and metabolic changes, they are not suitable for improving amateur endurance athletes’ performance.