I don't routinely cycle, but intermittently cheat, preceded and followed by intermittent fasting. Excess carb intake isn't good but insulin response is what's key. I pretty much stay in the guidelines of the keto diet, but I often do 24 hour fasts, which is having just one meal a day....a big fatty meal that is, and from time to time I do a 40 to 42 hour fast which is just picking a day to not eat. Keeping insulin responses to a low that way gets you deep into some fat burning especially if you are keto going in and coming out of it. An example of a 40+ hour fast is; Eat dinner at 6pm, wake up and not eat that whole day, go to bed, wake up and try to push eating out to 11 or 12. For perspective, I'm pretty lean and stay extremely active. Once fat adapted, it's easy to fast and stay active at the same time, and when I'm not fasting I'll eat 3 to 4 meals a day, watching my carbs.