i've read similar things and have experienced it first hand. when it comes to the business world, it absolutely counts. who would you hire: the fat dude with more experience but is self-conscious and comes off as being possibly lazy or dirty, or the clean-cut fit applicant with less experience but speaks with confidence and presents themselves more professionally?
obviously, the latter. by being in good shape you're naturally confident in your presentation, helping you feel more confident in your actions and words. ntm, in a world where fitness is a very big thing right now, people respect those that are in shape. it shows dedication and success, which clients love to see.