Mobility has a huge role I believe in long term fat loss, but probably not in the way you were thinking.
Behavior issues are full entwined into the reason for maintenance of fat loss, since nobody is putting food into your mouth other than yourself (in a vast majority of cases).
One thing that I think plays a HUGE role, although I don't see it talked about anywhere is how YOU (and your brain ) perceives your body.
Say I am overweight, I get my nutrition in order, hire a coach/trainer and drop 30 lbs of fat. Whoo ha!! Awesome work! Seriously that is an amazing job!!
The trick now is to no regain the fat! The issue I think is that most of the time, you still have a "fat person's maps." The brain integrates "movement maps" as I learned in Z Health R/I Phase taking inputs from the joints (proprioception), eyes (visual) and vestibular (inner ear/balance) to form my overall body map.
Now if I drop 30 lbs and I don't do any work (primarily mobility and some times visual/vestibular) to update my maps---at a base level my body is much thinner physically, but my brain still thinks I am 30 lb overweight! Uh oh. Guess what happens next----I will tend to slip back to behaviors that match what my brain perceives. This concept is taken from the book "The body has a mind of its own"
Physiology is messy, completely non linear and has lots of "bad" engineering words (anisotropic, etc). See the post You Body as a Black Box for more info.
It is my biased belief that for most people following a good nutrition system (I use Precision Nutrition) and intelligent training that work to update your body maps is the best direction to go for 95% of people. Plus most want to move and be treated like athletes So if you were to stop in at my place, you will only see the basics--a power rack, bars, kettlebells, sandbags, big tires, sledge hammers, etc. No fancy shining equipment but it gets results and is "fun" in a weird, twisted way. I think trainers should spent their money on top of the line BASIC equipment and then keep spending on education.
Speaking of education, I am off to Charles Staley's Training Sumitt in AZ now. See Wed's post for info and hope to see some of you there in AZ.