If you have small children, you know that you can't give them their drink at a meal until after they've eaten a substantial part of their meal. This is to prevent them from getting full on water and milk before getting the nutrients they need from their actual food.
This rule does not apply to adults! I find that I often forget to drink while I eat. When I don't drink something, I typically do not feel as satisfied from a meal and then want more. That is one of our body's tricks. It sometimes makes us feel hungry when really we need hydration.
By adding a glass of water to my meal, I feel full faster and am less likely to overeat. So make sure you are drinking while you eat. If not, add some water and see if it helps you stay on track with your healthy eating.