I can tell you on any given day how much I weighed that morning, as well as how much food (calories, and grams of fat, carbs, & protein) I consumed. The only exception are the days I ate at a restaurant.

I think the two key things to maintain a diet program is to (a) play very close attention to food labels, and (b) track everything you consume. I created Excel charts for both.

When food shopping for new food items, I look at it's protein & carb totals. If it's very heavy in carbs, I pass. If it's fairly balanced, I may add it to the diet. I don't give dietary fat a second thought. Fat is good...it keeps your feeling satiated.