So far, after 20 years of competitive rowing and an office job, I've found the best advice for me is simply don't get injured, remain active (get out!), and cook more. All these fads might work (IF, keto, crossfit), but I think they mostly answer other questions than fitness or health. People want to feel like they are getting results fast... That is rarely sustainable in my experience and observation.
keto is the best way to lose weight, period. You lose weight while not even trying ... it really is the miracle diet, for most people anyway. Gives great mental energy as well. (yeah, sounds like bullshit, but turns out to be true for lots of people)
I agree that, for a given caloric deficit, a ketogenic diet produces less perceived hunger, so you "lose weight while not even trying". However, keto also keeps your glycogen stores low, which reduces cardiovascular performance while the diet persists. This makes keeping muscle harder, especially if you have a lifestyle with requisite cardio (e.g. bicycle commuting). I don't think high-intensity cardio + keto is a good idea because, in the absence of glycogen, the body can tap muscle protein as a peak-power energy source.