More variety of meals
Most people revert to the same old foods if they don't plan their meals. Truth be told, it gets boring after a while. With meal planning, you'll be more conscious of including a variety of foods in your diet, because once you see the same foods on paper, something tells you to change things up a bit. Choose from a variety of recipes and you'll begin to see the benefits and joys of a more varied diet.
If planning multiple meals seems overwhelming, start with planning a variety of dinners, and see how that goes. If you like the results, plan your next lunch, and if you like the results, add in snacks. That means you can never become a spontaneous eater again, it's just that you'll become a more planned person. Planning a more varied meal is also a way to love yourself, giving yourself the opportunity to taste more delicious dishes.