Most people who live in lands where food is plentiful know the feeling of a “food hangover”. This is when you feel like crap the next day after overindulging. This feeling is often accompanied by a sense of wanting to have a really good day food-wise. You feel so sick from having had too much of what you love so you want to stay away from the source.
This feeling also plays a part in a lot of New Year’s resolutions where people eat every decadent treat in sight during the holidays and then vow to lay off of such foods in the coming year. One of the reasons that such resolutions start with a bang is that mentally people are saturated with food-based stimulation. If you’ve had chocolate, cookies, cakes, etc. for weeks on end, they start to lose their appeal and you find it much easier to face a bowl of oatmeal or salad. The novel was the norm so the norm now becomes novel.
Ultimately one of the reasons people either stop dieting after awhile or regain weight is that the hunger for tasty food will never go away. It’s part of your biology to want these things because energy dense and sweet foods helped your ancestors survive. What most people do not seem to strive for, but naturally thin people seem to do without a second thought, is how to not overdo one way of eating or another. That is, eat everything in moderation so that you feel neither deprived nor overwhelmed.
For me, one thing that helps when I have the impulse to overdo something that is not good for me or is densely caloric is to remember how unappealing treats and snacks became and how crappy I felt physically after holiday-induced stints of bad eating. If I remember that the ultimate consequence of such prolonged indulgence is that I don’t enjoy those foods for awhile, it’s helpful in moderating consumption such that I feel the experience remains novel and special. It also reminds me that eating junk isn't what my body really wants, but rather what my mind is telling me it wants.