First, I was surprised to learn that I was eating way too many calories. I never would have limited myself to 1200-1550 calories if not for SparkPeople. I learned that a serving of Ritz crackers is 5 crackers (sometimes I'd eat most of a sleeve and really not even feel too guilty.)
I learned that 8 cups of water is kinda hard to drink unless water is your only beverage, and then it's pretty easy.
I learned that I tend to eat a bit too many carbohydrates and a little less protein than I could. And I learned that when you only have 1200-1550 calories to spend, NONE of it can be junky. To get your nutrients, every bite has to be wise and mindful, down to the last tsp.
I've also learned how to gauge how much food will get me under my limit. The first week, I only managed to stay under the limit twice, and I was quite hungry. This week, I feel like I can probably stay under the limit any time I want to, even though I'm still a bit hungry.