Why eat less and move more is useless advice

We all know it: to lose weight we all need to eat less and/or excercise more. Even Stephen Hawkings said so : "We eat too much and move too little". Givin the fact that Hawkings cannot move at all, while he seems to be almost anorexic, this comment is more than just a little ironic. Because the thing is this: while you indeed need to be in a caloric deficit to become smaller the idea that you can ONLY do this by moving more and eating less is overly simplistic and woefully incomplete.