I initially lost about 45 lbs (217 – 172) in about 10 months, but have since leveled out between 170-175. Beyond the weight loss, I noticed marked improvements in general energy levels, sleep quality, and chronic issues such as heartburn. More importantly though, I think the biggest adjustment that IF enabled me to make was transitioning into _wanting_ to eat healthy/whole foods and cut out foods with processed carbs and added sugar.
But I totally agree, there definitely is a psychological aspect of it, whether the improvements are quantifiable or not. Maybe the results are placebo, maybe it's confirmation bias, but I definitely think that IF allowed me to reframe the way I approach my diet, and eat in a way that is more attuned to being healthy.
It hasn't been life changing in itself, but I found it to be beneficial for keeping my body weight stable, which in turn improves a bunch of other health outcomes. It could just be placebo, but I feel much better with IF.
Does it really work? I don't know, the scientific evidence isn't that strong at the moment.
But it has convex outcomes: if it works, the upside is tangible... and if it doesn't, the downside is negligible.