I don't know how many people who have dealt with this but I am sure there are those who have.
My mother has always had badly/inconsistently treated mental illness. Doctors can't really agree on if she has dementia or not. But in the past year, she has gotten really strange about food. When it comes to leftovers, she goes through periods of wanting us to eat leftovers then periods of not wanting us to eat them and then she gets mad when food has to be thrown out.
She just recently gotten nasty in the past hour and had me clean out the fridge. I had no issues with cleaning out the fridge, it was her tone and body language that really got to me.
For context, I have problems with textures and smells with a lot of foods due to autism and ADHD. Peri-menopause and PCOS makes it harder for me. She said it doesn't matter if I use weight loss medication, I will always be fat. She jumps on me on when I eat anything. The portions are "too big" or "too little" and it makes me feels bad and it's no wonder I turn to junk food and eat mass quantities of that or my GI system gets upset and stays upset with her behaviors. This is not making my depression any easier to contend with.
Things won't get better for you until you live many many miles away from your mom(like maybe 1000).
Until then make sure you're seeking a good therapist to help you get on the right track with your mental health and the choices you're making.
In the meantime, eat what you want and let her eat what she wants. If she makes a comment about what you eat, say nothing but take your plate and move elsewhere.
If she's not capable of ordering her own groceries or preparing her own food, set her up for Meals on Wheels and she can just eat what they deliver. The meals are planned to be healthy for an average elderly person's needs.
If you're in perimenopause that means you're well into adulthood and don't have to live with your mother and tolerate her abuse. You deserve so much better than this. Chart your path for independence and peace of mind. Let us know how things go.
My mother helped me create SUCH bad food issues from childhood, it's was ridiculous. The only way for me was to get out of her toxic environment.
Wishing you the best of luck. I get it.