Old peoples' eating capacity

I am closer to 90 years old than to 80.  As I grew up, I didn’t hear much about oldsters eating.  I am surprised by how much less I can eat at a meal than I used to eat.  We recently ate out.  We had a good meal and brought our leftovers home.  When we ate the leftovers, we didn’t finish them in one sitting.  Mind you, that was with meals said to be for one meal.