Basically, there was a theory that exercising self-control would "deplete" ones "self-control reserves". The idea was that exercising your self-control, to say avoid a junk food, would temporarily decrease your ability to resist that temptation again.
This paper reports that not only were they unable to verify any of the prior research into this so called "ego depletion" effect, but they found more persuasive evidence suggesting that the theory is false.
This paper reports that not only were they unable to verify any of the prior research into this so called "ego depletion" effect, but they found more persuasive evidence suggesting that the theory is false.