Is this from "Thinking, Fast and Slow"? If so, how do you know it's not actually the break/rest that helps, rather than the food? I don't see any controls in that experiment take a break of equal length but not eating, and others who ate without a break.
Anecdote: I discovered when quitting nicotine that first thing in the morning and after lunch were the times when my willpower was weakest. Your mileage may vary.
