Mom forgets she's eaten and wants to eat again.

It's very common! - and I think the first time must be memorable for everyone. In our case, it was while I was still finishing clearing the dining table when my mother said mournfully: "are we having supper today?"

What, you mean apart from the soup, the roast chicken and roast potatoes and sage and onion stuffing and vegetables, the apple crumble and custard that you've just put away..?

My MIL/GMIL is 80, has had 4 strokes, 100+TIA's diabetes, High and low BP, bed bound after last stroke and TBH if she wants cake or ice cream sandwiches so be it as long as she's eatting something. I have the meds to bring her sugar down and if it helps the evil twin from popping out so be it! She's been thru enough and survived if she wants foods bad for her ( within limit) so be it. It makes her happy.

When I have dementia, I want my family to feed me all sorts of bad for me foods that taste great and will take me out with a sudden heart attack! If you can't afford the food that's one thing, and if she has diabetes it would not be good, but if none of that applies to her situation, I say, "let them eat cake!"

We had a scale here hooked up to the telephone line. Hubby, with CHF and LBD, weighed himself daily. If he went up a few pounds suddenly (which would indicate water weight) the nurse would call. Here is one conversation we had:

Nurse: Coy's weight is up 3 pounds.

Me: Oh. That must be the pickle he had in a German restaurant yesterday. Should I increase his diuretic for today?

Nurse: A pickle! Don't you know how high in sodium those are? Why did you allow him to have a pickle?

Me: Dear Coy has a terminal condition. My goal in caring for him is to ensure the highest quality of life for as long as it lasts. I am not depriving him of any foods that make him happy. I am glad to see when he starts retaining fluid and to take steps to minimize that, but I am not going to enforce a very restricted diet. If you want the scale back just let me know.

Nurse: No, keep weighing Coy. Some monitoring is better than none.

In other words, my philosophy was like Surprise's. I might add that Coy was a dedicated foodie, as I am. It might be different for people who are not that interested in food to start with, but for me, if/when I have a terminal condition, for heaven's sakes folks, give me all the pastries and mashed potatoes I want!

And I'll also add that I had the encouragement of both Coy's geriatrician and his
neurologist. Coy had followed a heart-healthy diet for years. Now it was OK to let loose and eat what he wanted to.

BTW

It doesn't help to show them evidence of what they just ate either

Look there's your empty plate - response is usually
That's not mine

Mom's caregiver found her arguing with other residents yesterday claiming they took her dessert
They didn't but she ate hers and saw others still had theirs so ergo

That's what I'm thinking regarding my dad with bad diabetes and all the other problems that are starting to surface.
He loves my homemade macaroni and cheese made with Velveeta! And fried egg sandwiches with mayonnaise ! When he eats these things he looks like a little child in a candy shop and is so happy happy!!!!
I'm with you surprise ...... quit giving me all the Band-Aids to keep me going and give me some cake too!!!!!

: - ) in my Mom's early stages I was visiting every day and knew she was safe (in independent living of a secure continuing care community). So I brought groceries one day and the next day all 7 bananas were gone. Typically she would have one in the morning! Well, each time she went to the bathroom, apparently she thought it was morning! LOL It was a wake up call that my Mom needed more help!

Not a big deal, no, but could you perhaps try telling her what the next meal is and when it will be, instead?

And if she's really, really hungry - ? - then unless her weight is a serious problem give her a little something to tide her over.

My LO is the same way. She forgets that she ate 2 minutes ago and the thing in her tummy that says I'm full doesn't work anymore. So, we have to make sure that she doesn't make herself sick. She would eat nonstop if not managed.

If she doesn't have a weight issue, I'd likely give her a little more food. Does she normally ask for second servings? Is it possible that she's really still hungry? I might calculate how many calories she's getting and make sure she's getting enough all through the day. If she's getting enough, I might offer fruit or jello. Or put a couple of cookies in the package and say that's all that's left. Maybe, she'll see they are the last ones and that will convince her she's had enough.

You might also mention to her doctor. Sometimes diabetes can make you incredibly hungry and so can low blood sugar.

Give her a healthy snack. Apple and peanut butter. Cracker and cheese. Humus. Avocado toast. Something satiating. Cup of yogurt with walnuts or blueberries. Cottage cheese with peaches or pears or pineapple. Multiple small meals are healthier than three larger ones. If eating mostly carbs she will get hungry quicker. Add protein and healthy fats. Having said all that, I think it's fairly common for folks with dementia to forget if they have eaten. Telling them they have probably won't work.