Well I don't really have any science to back it up, but they way I did it was keto on off days, and then on training days I would carb up at night with whatever I wanted (pizza, ice cream, pasta, whatever - assuming you've stuck strictly to keto on your off days and during the first half of your training days). I always train in the morning though, so this "carb up" would never be directly post workout. Surprisingly, I would often wake up leaner on days that I carb load at night. Idk it worked pretty well for me, but i only did it for like a month. When I go to lean out for the summer, I plan to use this dieting approach as well.