If you're wondering why most diets fail, this might be the reason. If you do too much, chances are good you'll give up. "A lot of people bite off more than they can chew without knowing it," said a Redditor. "If you can't stick to a diet for more than 3 weeks then the diet was too hard for you. Next time pick an easier diet. If you are constantly going over budget every week, then your budget is too tight. If the budget has to be tight and you are still over spending, then examine the emotional cause for the spending (assuming you aren't subsistence-level poverty)."