Unless you are a child, eating more is no problem. But, if you are an adult, eating less is good to you in every point. It is because if you eat less, your stomach will have more space to digest your food, which you have eaten. If you make your stomach full, it will then have no space to digest your food thus causing many kinds of illness sooner or later. Besides, if food remains in your stomach too long, it will produce poison ingredient which will make your whole body uncomfortable and eventually you will be sick.
But, if you eat less, your stomach can digest food easily, making your whole body in high spirit in all day long.
Besides, if you eat less, your stomach will tell you what you will like to eat today. If today you like to eat meat which shows you lack of protein in your body. If you like vegetables, it is a sign that you need vitamin C. You do not need to eat expensive food, just to eat what you like today. That is good enough for your health.
Many old people die earlier than their nature death period, because they eat too much, especially the beef is the dangerous killer if old man eat at dinner time. Many middle aged men also die at their prime age because they, by their success in business, live a very crazy life by drinking and fooling around up to late night. As a result, they die before their sun-set age.