Yeah, this study seems pretty shallow and fails to take into account other indirect factors which might influence obesity rates (so it's not necessarily A->B, but possibly A->B->C->...->Z).
Human culture and gender differences is overwhelmingly complex subject. This research is trying to establish direct relationship between estrogen and obesity, but hormones might have subtle but signficiant effects on human culture.
It is even bigger than all of the Web browsers, which can perform all the tasks as Tex and many other once.