Step 1: Re-connect it with something negative.
What happens is that your mind connects the food with a positive emotion. The short rush that Ulv explained above. So what youre basically after is the emotion the contents of the food gives you and not the food itself. You cant stop because you are addicted to these emotions.
Theres many ways of re-connecting food. One thing would be to find a video that really gross you out. Maggots or something like that. Watch it as you eat. If youre able to do that 2-3 times thats enough. I promise you, you wont desire that particular food/meal anymore
VERY IMPORTANT THOUGH: Food itself is great is for you. You should enjoy food in a natural way and NEVER get to the point where stop eating. So make sure to make step 1 the short term fix and step 2 the long term fix.
It is purely based on the suspicion that you eat unhealthy food. If youre eating vegetables all day, keep going
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Step 2: Get to the ROOTS of the real problem.
The eating is the symptom of the real issue/problem, but not the problem itself. Why would you crave for these short lasting emotions? What do you feel that is lacking in your life? Who or what is hurting you?