Is your loved one with dementia sleeping a lot (too much)?

My problem is eating everything in sight. If it is reachable, she wants to eat it. She can't remember that she just ate a cookie and wants another when she sees it. I'm not sure what to do. I try to stop her but then she gets upset as "Why are you keeping that from me?"

HI @goodold, my husband is the same.
He forgets he ate and looks for more food. He circles food like a shark and wants to eat what's on my plate as well. He hovers near me in the kitchen ready to take what I'm preparing before it's fully cooked or ready.
He doesn't feel full or satiated. I wonder if that involves damage to the brain.
He's put on about five pounds and I was told he was prediabetic (at the low end) so I monitor what he eats closely. I don't have cookies or candy in the house and I stopped making muffins as he can easily eat a few. I give him fruit as a snack, but limited, as it can be high in sugar.
I lock the refrigerator at night. Originally I did this because he was scheduled for surgery and couldn't eat anything from midnight the night before. I was worried I wouldn't hear him get up and be able to stop him eating. He didn't like it, but accepted it graciously enough. Since his surgery, about 10 weeks ago, I've continued to lock the fridge at night. It broke him from the habit of going into the fridge at four and five in the morning. He was eating about three small breakfasts before the locks. Now he doesn't even try to get into the fridge.
One suggestion I read about this is try to spread out meals over the day - so don't serve all the food at once. Maybe give the main meal, then salad and a dessert later.
Have healthy snacks available. I just made a high bulk salad - sauerkraut, green beans, apple, carrots, a few dried cranberries, and garbanzos that he can snack on without too much damage. Also, nuts, in moderation, are good.
Thrist is often misinterpreted as hunger. It's important to stay hydrated. I make weak iced teas, some herbal that taste like juice when sweetened with stevia, and give him fat free milk, sweetened with stevia and flavored with cocoa, which he loves. He has osteoporosis so needs calcium.
We also walk daily if possible for about 25 minutes.
This is a challenging aspect of this disease for sure. I wish you the best!