Has anyone noticed significant behavior changes when giving candy to those with dementia?

I have never liked Halloween, now even less so. I think mom has a sugar addiction and I try to keep her candy intake to a minimum. But this morning, at her hair appointment the stylist gave her a mini candy bar, then mom got another one, maybe two. When we first got in the car she wanted to go buy more candy. I told her we couldn't do that. She became quite angry, wanted me to take her to a place where she can take care of herself.

This is not the first time this has happened when she has candy. The problem is she wants more and more and more. She would eat a whole bag without realizing how much she has had. I really think she has a sugar addiction that causes this aggressive behavior. Anybody else ever see this?