I've been fortunate to keep my weight within a reasonable range for most of my adult life.  I grew up in a family that didn't have the best easting habits and my mother was very heavy and some of my sisters also went down that path.  Early-on I figured that food could be my ally or my enemy, and so I chose to make friends with food.  If I want something I eat it and enjoy every bite.  But if it's high in calories, I don't repeat that behavior every day.  I also use my plates and bowls differently.  I fill my dinner plates with a big bunch of salad greens, then I make a pyramid of ingredients.  Those that are lowest in calories get the next layer on the plate, but a smaller quantity than the greens.  For instance, I might want to add black beans or bell peppers, and various vegetables.  Next layer up but less quantity than the vegetable layer will be some sort of lean protein like roasted turkey breast.  Next layer up but less quantity than the protein is some sort of low-fat dairy product such as fat-free feta cheese.  By now, you should be seeing a sort of pyramid with the heaviest calorie item on the top and the lowest on the bottom.  I top this off with some diet dressing and go to town enjoying it.  I use my salad plate to have my dinner.  One-half is filled with any kind of vegetable I want.  The other half is divided so one-fourth of the plate has some type of starch (sweet potato, pasta with tomato sauce, etc).  And the other one-fourth has some type of lean protein such as skinless, broiled chicken breast.  This has been an easy way to keep calories within a reasonable range without getting out my calculator for every meal.  I'm refining this a bit and will figure out which of my bowls represent one-half cup and I will use those for calorie-rich items such as low fat frozen yogurt.  And which of my bowls represent one cup which I'll use for fresh fruit.  I find when I do this, I am able to re-train my eye to understand what a "portion" really means.  My plate is full and that also helps my brain and stomach to not feel deprived or on a diet!