Carb cycling isn't necessary on keto. Protein, especially whey, triggers an insulin surge similar to carbs without spiking blood glucose, while also raising glucagon to promote fat burning. You get the metabolic benefits without the carbs.
Do you need to carb cycle if you're keto? Do you need to carb cycle to be metabolically optimal? In my opinion, the answer is no. No, you don't. And that's not contradictory with what I've said thus far. Let me explain. I believe you can, for lack of a better term, hack the cyclic metabolic switch. Remember, refeeding refers to giving your body a growth stimulus. And while growth pathways are complex, one could argue that insulin is the most relevant growth hormone. And you don't need carbs to spike insulin. Protein also spikes insulin. In fact, some proteins like dairy protein and especially whey protein can spike insulin so much that in some people it spikes more than bread. But don't expect to see the same jump in blood sugar when eating whey protein as compared to eating, say, bread. Because protein doesn't have sugar. No duh, right? And protein also increases other hormones like glucagon which have distinct metabolic effects like promoting fat release. So while protein won't burn fat off your body just by itself, the hormonal profile and impact is distinct from eating protein versus eating carbs. Kind of obviously. Hopefully. And yet you do get the growth signal and the insulin spike from protein, especially whey protein. And this is why I don't think you need to carb cycle to activate this cyclic metabolic switch.
