Fighting the feeling of "I deserve it"

This was my first abstinent Erev Tisha B'av. In many ways I found it harder then Erev Yom Tov. Even though the house was not full of yummy treats my mind was playing tricks on me. It kept saying "you are not eating tomorrow you deserve more food". My sponsor told me that my davening will make a bigger difference to how I feel then my eating. Daven to Hashem to give you an easy fast and it will make a bigger difference then how much you eat.
Baruch Hashem she was right. I made it through Erev Tisha B'av abstinent and I am feeling better then other years even though I did not binge yesterday.
On a rational level I can say that my body is used to getting by with less but I know that it is a gift from Hashem.