When we restrict a food out of fear that it will cause weight gain, that food gains power, or "charm" as I like to call it. The brain's perceived scarcity of the food makes it more appealing.  Think of it as the "eat it all when you can because you don't know when you're going to get it again" effect.  

So to decharm the food we must systematically habituate it, meaning eat it repeatedly until it no longer has charm.  Literally eating it at every meal and snack for as many days as it takes.  

This process tends to freak people out.  So let me reassure you, it's not a license to overeat.  We're actually training you to experience what it's like to eat this food in smaller amounts.  

The neurobiological effect is that the brain gets less excited in the presence of this food and there's no longer that drive to keep eating it past the point of satisfaction.   There's a lot of research on this topic in areas additional to food.  For example, when you get a new shirt it's really exciting at first to wear it, and then after you've worn it a few times it's no longer as exciting.  

So if you're ready to try this experiment here's how:

• Pick a food that has charm.  Be specific.  Just saying "cereal" won't work.  It needs to be the exact same food repeatedly.  
• Determine how much of that food to have at meals vs snacks.  Simply replace something else that you would have eaten with the charmed food (e.g. eat the cereal with your dinner instead of rice).  Eat the other foods with your meal as you normally would.  You will need these for satiety.
• Eat the charmed food at every meal and snack until it is no longer appealing.  This may take just a few days, or even a few weeks.  Be patient.  Don't stop until you're sure.  If you stop and then realize it's still charmed, start over. 
• Continue to listen to your body's signals for hunger and fullness.  This is not a prescription for overeating.  
• Once you've decharmed the food plan to continue having it consistently for a while to reassure yourself it will always be available. 

If you're trying this and struggling call a dietitian who specializes in intuitive eating and s/he can guide you.  It's a challenging and difficult process to do on your own and having some expert guidance tends to be helpful.