The hallmarks of an addiction in question here include things like compulsion (where a person wants to stop partaking of something, but finds they just can't stop) and dependency, where a person wants to stop partaking of something, and when they attempt to do so, they find themselves experiencing physical and psychological discomfort (the so called 'feeling out of sorts') which 'magically' disappears upon getting their usual 'fix' of what they are addicted to.
Now the problem with 'socially sanctioned addictions' like food addictions (in this case fast food addiction), is that there tends to be no rehabilitation or social support programs aimed at helping people overcome them. A person trying to overcome a fast food addiction will therefore typically have to trudge on the arduous road towards overcoming an addiction on their ownand this can be a tricky affair.
Yet it is still possible, with the right mindset, to overcome a fast food addiction.The first step towards overcoming a fast food addiction, as indeed any other addiction, would be the acceptance of the reality of the addiction: accepting that you are actually addicted to fast food. The next step would be making up your mind that you actually want to quit, because unless you actually make up your mind that you want to quit, you will find yourself approaching the quitting halfheartedly, and often sabotaging your efforts. Having made up your mind that you want to overcome your fast food addiction, the next step would be developing a quitting strategy, where commonly given advice is to quit in graduated steps (like where you first quit for a day, then two days, then a week, then a monthtill you get to a point where you can't recall what fast food tasted like!). In this program, you have to be ready for tricks your mind is likely to attempt playing on you - like making you feel 'out of sorts' for not partaking of the fast food. The advice with regard to this is to simply ignore these feelings, which are the equivalent of your mind throwing tantrums, as they tend to go away on their own, when ignored. In the meantime, you will have to substitute the fast food for healthier - but equally tasty - alternatives to it, of which there is a great variety nowadays.