Mom is not eating normal. She says she doesn't know how she feels. Should I call the doctor?

Yes....even more critical if on meds.
if someone says they don't feel well
But don't know what's wrong we need
To do some checking.
why not....its paid for via Medicare.

Definitely, as a diabetic it is important to keep an eye on her blood sugar. My husband was a diabetic, type 2. I checked his numbers first thing in the morning, then 2 hours after eating. Glucerna is an excellent suggestion, when he did not want food, I always could entice him with his chocolate milkshake, as I called it. And the Glucerna bars. Putting the food on smaller plates with bite size pieces helped too. Do to his stroke he really couldn't taste very much - all seem to be the same to him, except his Glucerna. Do talk with your doctor as soon as possible to make sure there is nothing else going on.

Since she is diabetic are you regularly checking her blood sugars? Is she type 1 or 2? My 83 year old mom is type 2 and on medications...just had a discussion with her doctor about her changing eating habits. Some days she just doesn't want as much to eat...I check her numbers and if they are too low I just don't give her the meds (like I said, I checked this out with her doctor first as I am not one and certainly don't want to play at being one but I don't want mom going into a low sugar coma either!). I would definitely touch base with her doctor.

lMy mom rarely just eats a whole bowl or plate of food straight through. Usually she takes a few bites and then says, "I can't eat any more." If I say, ok, and leave it alone, sure enough, about five minutes later, she will look at the bowl, like, "oh, what's this?" and she'll eat some more. If she is determined that she doesn't want any more, I'll take it away and wait a few minutes. Then I'll say, "Mom, would you like some (soup, toast, whatever it is)? Most of the time, she'll say, "Oh, yes!" and happily eat some more. I've also begun putting her food in smaller bowls, maybe on a regular size plate or bowl, it looks like too much food and it's overwhelming to her. It also helps to serve everything in a bowl, because with low vision, she chases the food around on a plate and has trouble getting it on the fork or spoon. Also, she has trouble using a fork, she stabs at the food and it comes up empty, so I mostly cut everything up into small pieces and give her only a spoon. I think if it's too much trouble or too much work, they get tired of trying or lose interest and quit eating too soon. Also, they may have lost some of their sense of taste, like when you have a cold and everything tastes flat and like pulp. My mom enjoys her food more if I use one of those spice mixes and shake on extra. I even sprinkle on a little cayenne pepper, and she loves it and never has any stomach problems from it.

Are you saying that she's stopped eating or that her appetite isn't quite what it usually is. As she is diabetic, it's certainly important that she gets the right amount of calories; missing a meal isn't an option. Have you tried the Glucerna shakes or meal replacement bars? They also sell the shakes in powder form so you can mix them yourself at home. They're specifically for people with diabetes. They should be available at your local pharmacy or Wal-Mart. If you go to Glucerna's website there's a coupon available, too. ;-)
Do call her doctor if she continues to have issues. There could be something else going on that accounts for her lack of appetite, anything from constipation, a urinary tract infection, depression--any number of things.