My wife almost cries sometimes when my girls refuse to eat the dinner
that she sweated for hours to cook. She was not a great cook before we
married, but when she was home with the babies she made a real effort
and now she is really pretty good. I think food represents love for a
lot of people. If you reject someone's food it is felt as a kind of
rejection of that person. Also if you (or your kids) eat the food she
gives you, she feels happy and accepted. Maybe she worked hard
learning to cook the foods she does, and does not feel confident with
unusual changes, though most paleo foods are very simple.

It is hard to change someone's lifetime food habits, if your mother is
truly concerned about you and honestly believes you are harming
yourself, of course she will try to "sabotage" you. Parents find it
hard to respect the opinions of even grown up children, and when you
are only in your twenties, you still seem like a child to them no
matter how you feel to yourself. The family is the basis of the whole
top-down socialist ideology, Mom and Dad know best. You have to
support your mother and find a way not to fight against her directly.
A kind of mental judo. Eat heartily anything proper she makes,
compliment her on it and look disappointed when it is all gone. Make
sure she has a clear, simple list of foods you do not want to eat, and
buy as much of the food yourself as you can. Make it easy for her.

All that said, people are strange, and Moms can be hard to change.
Practice forgiveness. Think happy thoughts and don't review negative
ones. It just isn't worth fighting over, life is too short to waste
fighting over food with your Mom.