Even that would be nonsense since muscles weigh more than fat tissue and people that properly exercise are likely to gain muscles and thus weight. For that reason, weight loss is not a meaningful indication of anything except for people that have the physique of a big sea mammal and thus are mostly fat anyway. Proper research should include diet and body fat percentage. Also, in general exercising more without losing much weight is already a big win for the health of most people. Stupid research like this only demotivates them because it fails to include all factors that are relevant to their health.