Sure, these probably aren't necessary for people whose parents taught them proper portion size and diet control. But some of us grew up with parents who <i>still</i> fight eating disorders. Two tools were instrumental in teaching myself how much to eat:<p>1. Calorie counting app. I use MyFitness daily and record everything in it. The app gives me one number -- how many calories are remaining for today -- on which I can focus and remember. Other apps are probably as good, I've never tried. This really helped me learn how to control my portions and stay honest with myself.<p>2. Calorie counts on menus. When looking at fast food, I'll remember how many calories are remaining for today, and I'll often change my choices. I've chosen the 300-calorie cheeseburger over the 600-calorie double cheeseburger many times, mostly because the difference was listed on the menu.<p>One of my goals was to change how I thought about food -- instead of being a magic elixir, it became a game: I have 2000 calories to spend today, but if I spend 600 calories on this burger, I won't be able to afford the 400 calories of beer I want to drink tonight. This is because I've already budgeted 1600 calories across my other meals. I've lost 80 lbs this way and maintained this lower weight for months.