Are you familiar with my 15 minute rule? Today when you make a plate, make it your normal portion size. Now take a second plate and divide it in half. Eat the first smaller plate then wait 15 minutes...yes, you can hold out.
See how you feel 15 minutes later. If you're still hungry eat a bit more then wait....do this until you feel "physically" satisfied. Mental satisfaction is something entirely different. It can raise havoc with your eating plan. "Boy that looks good I want to eat it" is not the same as physically needing fuel for the machine.
Interestingly enough when I find my portion sizes growing I go through the same process. I ALWAYS find myself NOT touching the second plate. After 15 minutes I analyze how I feel and in 100% of the cases I've eaten enough food. Give it a try and you may find you're eating TWICE the food you need.