Considering this purely as a thought experiment ...
A concern for the participants would be severe suppression of basal metabolic rate through a chronic low-calorie diet, and significant loss of muscle mass.
After all, low-calorie dieting (with yoyo weight regain) is a major contributor to the obesity epidemic. What kind of follow-up support would be available to prevent or minimise weight regain?
I am sure that better outcomes on average would be achieved via calorie-cycling (ensuring an energy surplus at least 2 days a week) plus obligatory physical activities, as the muscles are a key endocrine organ in regulating blood sugar levels, BMR and the immune system.
The approach in the thought experiment is too reductionist and short-termist IMO.
F 5 ft 3. HW: 196 lbs. Primal SW (May 2011): 182 lbs (42% BF)... W June '12: 160 lbs (29% BF) (UK size 12, US size 8). GW: ~24% BF - have ditched the scales til I fit into a pair of UK size 10 bootcut jeans. Currently aligning towards 'The Perfect Health Diet' having swapped some fat for potatoes.