Make sure you are consuming enough protein and fiber.
Hunger is no problem, if you eat the right things
Try nuts or chex mix its better for you than chips :)
You have probably sort comfort in junk food in the past and conditioned yourself to want it at certain times like stress, severe hunger, down days etc
Just like the Pavlov dog psychology experiment.
By knowing this you can retrain your mind by reconditioning the craving by reminding yourself of the conditioning and replacing it with something else.
My favourite is chicken bites .. A frozen bag of them...small handfull in the mirowave for a minute..if you want springle some flavorings on them.
The repetitive action of reminding yourself and replacing is like memorising your times table or lines in a play...it stays in your subconscious and you forget all about replacing but has now reconditioned your mind ..
We are not much different than 'other' animals despite how we are conditioned to think we are!
Maybe its not junk food cravings maybe its sugar.. try to replace your junk food with fresh, canned or dried, fruits and eat more vegetables too when i had junk food craving i would eat a stick of celery with peanut butter then after a while i just ate the celery alone
What I like to do is drink two full glasses of water when I feel like I have to snack, and wait 15 minutes to see if I still feel hungry. If I do I'll usually have a handful of nuts or some high fiber veggies, accompanied with another glass of water