This has been so true to me. At the beginning of the pandemic I started keto. The first six months the weight fell off then I just hit a wall right around the time I began exercising (a full season of skiing) and weight lifting. For the last month I've been combining keto with IF and I'm getting a tiny bit of headway. My body just seems to be fighting VERY hard to resist my best efforts. And while I'm not checking to see if my body is in ketosis, my diet is significantly more strict compared to when I started keto 1.5 yr ago. I keep doing keto (despite the plateau) because it has helped me in many other ways (sleep, asthma, chronic fatigue, mental health etc.) For reference I am 51 yo.