Have you ever felt confused after you ate a meal but very quickly afterwards you were hungry again?
I have a simple solution for you.
You are thinking in terms of a 24-hour time period, and not reflecting about your food intake over the last few days.
By this I mean you haven't eaten enough over the past few days.
Or, maybe you exercised intensely during one day like you went on a 10 mi hike, but you didn't replenish your body with enough food afterwards.
Or, as what often happens, you are under a deadline. You have a project due at work or some other event coming up and it's very stressful on you. And while you are stressing about this project or deadline, your stomach is shutting down.
When you're stressed, the blood in your stomach goes to your extremities, or your limbs, and this makes hunger harder to feel. Stress makes your appetite go down.
So in any of these cases, whether you're not eating enough, not replenishing your body after a lot of exercise, or your under a deadline, these are all things that build up over a few days.
And then one day, you eat lunch, and it's a big lunch. It should fill you up.
But the problem is you are only thinking in terms of that day.
You aren't incorporating your eating habits into your mindset from the past few days.
So you feel very confused because on a regular day this type of lunch would fill you up.
But when you haven't been eating properly over the past few days, this lunch is not the same.
Your body is playing catch-up.