first, define crappy junk food 'cause that means something different to different poeple.
for me crappy food is sugar and white flour, like cheeseburgers and soda. For someone else it's going to be french fries, cake...

i strive to the a day again when that kind of craving is rare.
what i figure is if you're in enough balance that you're getting this kind of craving, after checking it out and being clear on what it is you are craving - like do i want cookies or ice cream? - why not. it would be prefereable not to eat like pounds of anything but a small portion. That should take the craving away. Bingeing is what I think would lead to trouble.

and i'm also just not into denial of my senses. or letting fear drive. if it's what you want and you have it otherwise under control, there's no need to fear that your first cheeseburger in 6 months is going to kill you. Then you're likely to choose at least a healthier version of what you want, since the healthier you are the lower tolerance you're body's going to have to for empty food.

pick something. and eat it. i dare you.

what TYPE of junk food are you craving? a craving for sweets is related to spleen (earth) energy. are you vegetarian? do you eat fish? do you get enough omega 3's (healthy fats)? does your body temperature run hot, or cold? is your toungue red, or coated, or raw looking? do you wake up groggy and oversleep? how are your iron levels? are you fatigued and dizzy? it is almost impossible to discern why you would crave unhealthy foods if there is no profile on your normal habits.

i strongly suggest reading "healing with whole foods,' maybe even just go to your local health food store and browse through it (it's $35) and look up pertinent issues to you.

i would suggest this over going out and buying yourself a cheeseburger. it sounds to me like you are probably deficient in something.