The Ketogenic diet has been a trend in the fad diets industry because of its results in the famous body transformations (fat to fit). However, please don't get fooled about it as its efficacy stems in primarily two areas: calorie restriction due to reduced food variety and the fact that most of these people actually started training and eating more veggies than before.
For an in-depth review of the topic and whether it is effective in sports performance or not refer to the following review:
Margolis, L. M., & O'Fallon, K. S. (2020). Utility of Ketone Supplementation to Enhance Physical Performance: A Systematic Review.Advances in nutrition (Bethesda, Md.),11(2), 412–419. https://doi.org/10.1093/advances/nmz104