Why all the food issues?!

So Granny is soooooo crazy weird about her food.  She likes to snack ALL day, but won't sit down and eat a meal.  If, by some miracle, we actually get her to eat a meal, she freaks out EVERY TIME because there is too much on her plate and she "can't possibly eat that much."  Yet, after that meal she is snacking again.  I just don't get it.

And she seems to be ashamed when she eats or snacks.  She takes teeny tiny bites during a meal and always hides her snacks in the cup of her hands or under the table.  It's so weird, but I guess she doesn't want us to know she's eating.

Take just now, for example.  We were gone from 11:00 am to 1:30 pm to run errands that included a grocery store trip and we didn't eat or drink a thing.  I told her that we didn't have time to stop at IHOP when she wanted to go there just to get a cup of coffee immediately after we left the house.  (She will also tell you that she drinks several glasses of water everyday in addition to her million cups of coffee, but we all know how untrue that is)  We got home and I heated up 2 regular Sonic burgers that we got last night for the express purpose of having them for lunch.  I heated hers up and she cut it in half.  Then, sat down and ate half and started walking around scrounging!!  I told her that she couldn't have any chocolate or snacks until she had eaten the other half of this hamburger or the other half of her hamburger from last night that was still in the fridge.  

She kinda got mad at me, but looked in the fridge and added pickles to her hamburger and got a large handful of grapes at the same time.  She finished the grapes as she was taking bites of her burger and then opened a brand new box of granola bars we had just bought at the store.  (This is the same box of granola bars that she picked out and then griped about when we got home saying that she didn't like that kind and why didn't anyone ask her what kind she would like to have)  She proceeded to finish her burger and granola bar.  I was satisfied. 

Then, I see her eating ANOTHER granola bar!!!!!!  See why I don't understand it?!?!?!?!

She is always so concerned with food and fixing food, but she usually wants nothing to do with food other than snacking on sweets.  Grrrrrrr....it can be so frustrating.  I don't know if she's getting the vitamins and minerals she needs.  I can guarantee she gets enough chocolate and sugar, though!!