Creature of Habit??

I have been working out with a trainer once a week for the past few months and attending a pilates reformer class up to three times a week on some weeks. These are GREAT except, I totally still over eat. it's a deadly combination my too-big portion sizes and lack of planning (and tracking). Why can't I seem to get a permanent grip on this aspect of my life?
I would really love to hear from you if you have mastered portion control, planning, and honest tracking.
Thanks!!