kencc wrote: I think it probable that a major reason for subject1 becoming obese is that NEAT was too low; if subject1 had increased NEAT to subject2's level at the beginning then subject1 would have stayed at normal weight? Simplistic reasoning but I can't find an answer ... however maybe I'm too slow understanding stuff these days.
They got obese by eating too much
It remains a mystery to me too - the reduction in NEAT isn't matched to a reduction in physical activity so they call it "improved efficiency". They may as well call it "improved efficiency, errors and things we didn't measure" although to be fair there are references where they have measured the efficiency effect:-
http://www.ncbi.nlm.nih.gov/pubmed/12609816 " At reduced weight, muscle work efficiency was increased in both cycle ergometry [mean (SD) change = +26.5 (26.7)%, P < 0.001] "
https://www.jci.org/articles/view/25977 "At Wt–10%, the gross mechanical efficiency (GME) of skeletal muscle while bicycling to generate 10 W of power was approximately 23% higher than at Wtinitial and was fully reversed during leptin administration at Wt–10%lep."
So if they used some accelerometers and such to monitor activity it may have been clearer what actually changed, rather than calculating an energy deficiency as NREE and explaining it away as more efficient NREE.
In the end our only option is to do more stuff if we want to compensate, or just eat less to match our actual TDEE.