Everyone has been in carb burning mode all the time for so long. It's not healthy. Fasting for 24 hrs/ 2 meals puts you into ketosis. Doing it once a month is incredibly good for our bodies. Truly divine inspiration if you ask me.
It needs to be cyclical. Burn carbs, burn fat, burn carbs, burn fat.
There's more to it than just going into ketosis though. Avoiding inflammatory foods is just as important. Another reason people see such huge improvements with keto, they're all of a sudden eliminating so many carb based inflammatory foods.