Ugh, or the 'mistaken' belief that if they go for e.g. some fad diet (raw til 4, keto, whatever) that they can eat how much they desire without a single fuck given. Yeah, keto will help shed some water weight if you were originally on a carb heavy diet, but that doesn't mean eat 3000 calories a day in meat while you're at a desk.  Could you elaborate on the cardio not being important? I've always thought that if trying to lose weight, cardio was the thing to do (on top of reducing intake ofc), unless they're assuming you need to run a 5 min mile to gain muscle