As a recovering fast food junkie, I feel qualified to offer some advice
Because I was, until very recently, realllllly a fast food junkie. I decided when I first started this process to cut it out, and that I would reward myself once a month or so with some of my favorites. What I was surprised to realize was that once I cut it out, after only a couple of weeks, the desire for it did too. I know former me would have rolled my eyes at that and said "impossible." But I have read that there is actually something in the fast food that has the same addictive properties as nicotine- it's designed to make you crave more. So if you reward yourself after say, 2 weeks, with 1 burger and fries, you will then crave another fix far far far more than you craved the original "reward."
I don't know if this may be true for you, but for me, I had to decide to absolutely 100% cut out fast food. Now having said that, if I go to a real restaurant, I may order fries and eat a small portion of them. But I had to ditch the drive through mentality. I make a conscious effort to only eat "real" food that is more of a found in nature quality than a diluted, 3% actual food product, type thing. If I do have some fries, they may have plenty of salt and fat, but (I imagine) fewer chemicals, additives, etc. More importantly, I have stopped looking at a speaker and a window as a source of food. My advice is to use other food things for rewards. I don't mean all the carrots you want- but maybe a larger serving of something in your plan that you really love, but is still decently healthy. For me, a big part of this process has been re-educating my taste buds as to what constitutes food.