I eat 5 small meals a day, I don't think about it that way, 3 meals and 2 snacks. I am not sure what you are asking...
if you eat rice a part of one meal, you can't have rice with another meal that day. I often will add brown rice to a salad and then again to a chicken dinner to make it a complete protein.
I often have a difficult time reaching my intake also, but will make up the difference with popcorn at the end of the day (counted as a snack).
I will add cheese for calories if necessary.
I avoid all none whole grains, they usually has a few more calories with less sugars.
Also, when I am trying to add more veggies to a meal, I will opt for less starchy and add a grain or a bean to extend the calories.
It takes planning and working with the calorie counter to figure out what works with total calories.
I try to take most of my calories as a the main part of meals (snacks) and when I fall short I add extras, l like cheese, olive oil, etc.
be authentically you...
it's journey, not a one day hike.