As far as I can see, dieting has two dueling principles. (This is something I realized last night after pouring 3 c. of uncooked pasta into a pot of boiling water–whoops!) And in order to diet successfully, you must to buy into these equally important but seemingly contradictory principles.
Principle 1: If you set dieting rules for yourself–no carbs, low sugar, no processed foods, etc.–then you should believe that every successive day you follows these rules, the more likely you are to continue following them and eventually reach your goal. For example, if I am faced with a decision of whether to eat a bowl of cereal at 11 o’clock at night, I can choose to follow my rules and fight the craving, or I can be a weakling and give in. In an effort to resist, I must make myself believe that this one decision is not irrelevant and will contribute directly to my weight loss. Because if I don’t, then I will start eating junk food left and right, telling myself, “Hey, it’s just this once.” I need to believe that no, it’s not just this once, and in fact will be twice and three and four times if you give in. This is how you build a new lifestyle, not just fad diet.
Principle 2: To prevent complete implosion of the dieting, you must also believe that one lapse, one late-night order of French fries, one binge–that’s not the end of the world, and should definitely not spell the end of your diet. If last night was a fat night, then you must convince yourself that it’s a unique incident and can be undone with other, better decisions. That rhetoric you tried to use to convince yourself out of eating like a porker–it will begin a death spiral, this spells the end of any future weight loss ever–yes, rhetoric failed. And now you need to pretend that those threats aren’t actually true and you need to rebound.
If you can figure out how to manage those 2 branches of dieting and apply each when where appropriate, then I trust you can be a good dieter. As far as I am concerned, some days are better than others.