"I'm eating most of it" --> this isn't natural because your meaning is not clear; it kind of sounds like you have most of the food in your mouth right now.
"I'm going to eat most of it" --> this is natural but doesn't refer to you liking most food in general, it just means that you are going to eat a high percentage of your food that you are eating right now.
If you want to refer to liking most food, you could perhaps use some of the following examples:
"I'm not a picky/fussy eater"
"I'm a huge foodie"
And if you want to refer to something other than food, you could say:
"I have an eclectic taste in (movies)"
"I'll (read) anything"