I won't go full Keto, mostly because I just don't have the motivation and/or time to strictly adhere to such a lifestyle change. I am on the intermittent fasting program though and am liking its benefits thus far. I do a FDF (Full Day Fast) one day per week, typically Monday which is my rest day from training.
Beginning Sunday evening about 9-10pm, I'll have nothing but high ph water with added drops of trace minerals per quart bottle. I'll go through 1-1.5 gals of water in that 24 hour period, then break the fast with some bone broth, 1/2 an avocado, and maybe some nuts or a boiled egg.
I still eat within healthy limits for the remainder of the week, but don't worry as much about ingesting carbs when desired or necessary. Lots of whole foods, brown rice, meats when desired, etc... I'm cognizant of how much alcohol I consume, and sweets as well. I've found a balance that works for me and I'll alter the density/quantity of my calories based on my training load and upcoming race(s).
Each person will react to certain foods and nutritonal shifts differently so anything new, such as Keto or Intermittent Fasting, needs to be done with patience, a log of perceived effects, and finding your own personal balance along the way. If you have a doctor monitoring blood work along the way, all the better.