That’s a larger discussion but much of the economics of it gets cancelled out with the notion of “revealed preferences”. Economics doesn’t really account for whether an individual consumer is rational for buying junk food, scratch tickets, and liquor; it just sort of observes that you behave as though you want those things and models from there. The internal struggle of will between the “you” who binges on Oreos and store brand vodka and the “you” who wakes up on New Years morning with a hangover and a sincere desire to turn your life around isn’t necessarily within the scope of economics (unless the New Years Day “you” promptly purchases a gym membership that you never show up for!)