I don't understand...advice please?

I am SO new to eating healthy, and I honestly don't want to lose weight. I am just trying to be as healthy and happy as I can. However, I don't understand all of the macros for MFP...and I can never seem to eat enough. It says that I should eat at least 1600 calories a day to maintain my weight, but I barely ever eat over 1300. I try to follow the macros as much as possible but once I've gotten the amount of fat, sugar, protein, fiber, etc that I need, it normally says I am way under on calories. What am I supposed to eat? I don't understand..
I don't want to eat too little because I've been down that road and lost WAY too much weight and my body was going into starvation mode. But I am becoming frustrated because I don't know what to eat or how much, and I would like to understand the macros of MFP so that I have a solid backbone and understanding of everything I should be putting in my body.
Please help!