How to set boundaries with your parents
A boundary is something you will do, not something they must stop doing. Stated that way it does not need their agreement — which is the whole reason it holds.
What to actually weigh
Say what you will do, not what they must stop
"I will not discuss my weight" is a boundary. "You need to stop commenting on my weight" is a request they can decline.
Expect the escalation, plan for it
Boundaries with long-standing dynamics almost always get tested once, loudly. Deciding in advance what you do then is most of the work.
Separate the boundary from the relationship
You are not ending anything. You are changing one term of it. Saying so out loud usually lowers the temperature considerably.
Frequently asked
How do I set boundaries with my parents without hurting them?
You often cannot avoid hurt entirely — but you can avoid blame. Describe what you will do and why it matters to you, without a list of what they did wrong.
What if my parents ignore my boundaries?
Then the boundary becomes the thing you do, not the thing you said. Leaving the room, ending the call, or shortening the visit is the boundary actually working.