The times when I experienced the most drastically successful change when I realized that there really is nothing stopping me from entirely changing my identity and self if I so desired.
Obviously, this only works for things actually intrinsic (you cannot hit your target weight over night, but you very much can be a person who cares about their body starting right now and never go back) but holy shit, if you actually believe in your ability to do this, it is god damn effective.
Again there are shitty strategies for this (extrinsic goals, perfectionism, diet books, goals without systems) and it requires a healthy foundation of internal self-confidence that might take half a lifetime to build, but I still don't see the kind of defeatist attitude of the article helping anyone.