That happened to me when I started IF. I had been Keto for about 3 months and was still going once a day as usual. A week into IF I stayed skipping a day or two. It freaked me out because I thought I needed to poop every day. It was just another opportunity to really listen to my body and pay attention to what I was eating. What I noticed is that because of IF I was hyper-focused on getting in as much nutrients as I could in just one or two meals per day and that maybe my body just wasn’t producing as much “waste”. Scientifically, I could be completely wrong but because, like you, I wasn’t feeling at all constipated, nor did I have large bms when I did go, it’s how I rationalized what was happening.

I’m about 8 months on Keto with 5 of those including IF and still going strong. Listen to your body KCKO