Primitive Brain Fears

My Primitive brain believes that if I lose weight, I will be seen, maybe found attractive, and then be attacked.

I know this comes from childhood trauma.
In the past I tried fighting this belief, which led to a tug of war. Then I tried accepting it, which led to me gaining 30 pounds.
I am really struggling to know how to manage this thought: When I was thinner I was attacked, therefore it is too dangerous to lose weight.