There isn't any convincing evidence showing fat loss causes metabolic damage; however, observations are more indicative of reversible adaptive thermogenesis.
In fact, those Friday and Saturday nights were false points of pride for myself, because I felt I was somehow morally superior for exercising rather than having fun.
An overly-simplistic relationship between calories in and calories out doesn't cut and the scientific realities of weight loss are not that hard to understand so, learn a better way.