I won’t say 100% of the time but most of the time it is effortless when you’re in ketosis. Saying that however the switch from high carb/sugar to keto in the week leading up to the fast would not be a comfortable one.
I find fasting is a muscle, I’ve been doing it for so long whethere its omad or anywhere up to five days it really doesn’t matter if I’m keto or not.
I just binge a lot less when I’m on keto and don’t put the weight back on.
I guess on another note when fasting you find out a lot about your body’s needs, I almost always crave fatty meats and salads, never anything sugary or carby