There is a keto adaptation [1] period of at least 6-8 weeks where you might take a hit, but there are several studies that show that it's generally not a concern.
Cipryan, Lukas, Daniel J. Plews, Alessandro Ferretti, Phil B. Maffetone, and Paul B. Laursen. “Effects of a 4-Week Very Low-Carbohydrate Diet on High-Intensity Interval Training Responses.” Journal of Sports Science & Medicine 17, no. 2 (May 14, 2018): 259–68.
Greene, David A., Benjamin J. Varley, Timothy B. Hartwig, Phillip Chapman, and Michael Rigney. “A Low-Carbohydrate Ketogenic Diet Reduces Body Weight Without Compromising Performance in Powerlifting and Olympic Weightlifting Athletes.” The Journal of Strength & Conditioning Research Publish Ahead of Print (October 17, 2018). https://doi.org/10.1519/JSC.0000000000002904.
Paoli, Antonio, Keith Grimaldi, Dominic D’Agostino, Lorenzo Cenci, Tatiana Moro, Antonino Bianco, and Antonio Palma. “Ketogenic Diet Does Not Affect Strength Performance in Elite Artistic Gymnasts.” Journal of the International Society of Sports Nutrition 9 (July 26, 2012): 34. https://doi.org/10.1186/1550-2783-9-34.
Kephart, Wesley C., Coree D. Pledge, Paul A. Roberson, Petey W. Mumford, Matthew A. Romero, Christopher B. Mobley, Jeffrey S. Martin, et al. “The Three-Month Effects of a Ketogenic Diet on Body Composition, Blood Parameters, and Performance Metrics in CrossFit Trainees: A Pilot Study.” Sports 6, no. 1 (January 9, 2018). https://doi.org/10.3390/sports6010001.
If you're interested in the topic of human performance and ketosis, I enjoy Volek's talks - here's one from a relatively recent Jumpstart event: https://www.youtube.com/watch?v=BeS_dhM8dsY
Anecdotally, I find my workout recovery to be much better on keto/fasting diet, but all my markers (and overall inflammation) has improved so much and I'm being mindful of other aspects like stress, sleep, etc that it's hard to necessarily pin down to one cause.
Cipryan, Lukas, Daniel J. Plews, Alessandro Ferretti, Phil B. Maffetone, and Paul B. Laursen. “Effects of a 4-Week Very Low-Carbohydrate Diet on High-Intensity Interval Training Responses.” Journal of Sports Science & Medicine 17, no. 2 (May 14, 2018): 259–68.
Greene, David A., Benjamin J. Varley, Timothy B. Hartwig, Phillip Chapman, and Michael Rigney. “A Low-Carbohydrate Ketogenic Diet Reduces Body Weight Without Compromising Performance in Powerlifting and Olympic Weightlifting Athletes.” The Journal of Strength & Conditioning Research Publish Ahead of Print (October 17, 2018). https://doi.org/10.1519/JSC.0000000000002904.
Paoli, Antonio, Keith Grimaldi, Dominic D’Agostino, Lorenzo Cenci, Tatiana Moro, Antonino Bianco, and Antonio Palma. “Ketogenic Diet Does Not Affect Strength Performance in Elite Artistic Gymnasts.” Journal of the International Society of Sports Nutrition 9 (July 26, 2012): 34. https://doi.org/10.1186/1550-2783-9-34.
Kephart, Wesley C., Coree D. Pledge, Paul A. Roberson, Petey W. Mumford, Matthew A. Romero, Christopher B. Mobley, Jeffrey S. Martin, et al. “The Three-Month Effects of a Ketogenic Diet on Body Composition, Blood Parameters, and Performance Metrics in CrossFit Trainees: A Pilot Study.” Sports 6, no. 1 (January 9, 2018). https://doi.org/10.3390/sports6010001.
If you're interested in the topic of human performance and ketosis, I enjoy Volek's talks - here's one from a relatively recent Jumpstart event: https://www.youtube.com/watch?v=BeS_dhM8dsY
Anecdotally, I find my workout recovery to be much better on keto/fasting diet, but all my markers (and overall inflammation) has improved so much and I'm being mindful of other aspects like stress, sleep, etc that it's hard to necessarily pin down to one cause.
[1] https://blog.virtahealth.com/keto-adapted/