No actual science I can pull up or think of off the top of my head but my gut (heh) reaction is it’s no worse than just simply eating the carb heavy diet we’ve been forced all our lives (but the fasting would already improve on that). Sure you can eat healthier and maybe some day you’ll want to but if this is working for you, just listen to your body. It will tell you if things aren’t right
​
And people talk about low/no carb transitions for two big reasons:
First is your body is in a fat fuel using state and it takes literal days to get that back if you drop it - sometimes even inducing flu-like symptoms to get back in. It’s simply more effective to stay in that state
Second is that your fast will go a LOT easier if you’re already in ketosis. I’ve gone into fasts completely dirty (HEAVY carb eating right up to the fast), completely in ketosis through a low carb diet, and everything in between. Let me tell you - being in ketosis already makes the first 72 hours a BREEZE compared to other states. Not that you can’t otherwise - it’s fine to but it is a fair bit harder to get through the first 3 day hump
​
It all comes down to what works for you and what you’ll stick to, though. So unless someone has some reference to the damage the stress shifting is doing to your body (unlikely? That would probably have to be a pretty substantial and specific study?), don’t worry about it and just make changes as they feel important to you
I don’t know if it’s “bad” for you, but I also do this. I don’t have a crazy unhealthy diet (I don’t eat any fast food really, for instance), but I can’t imagine eating low carb long term. I will occasionally eat low carb or vegetarian, and often try to get a good amount of veg into any meal. I imagine, though, that fasting and continuing to eat as you normally do has to be healthier than not fasting.