Shortly after her 27th birthday, Jess and Dan, her fiancé, came for a visit. A few days earlier, she had sent me a link to a video called A Fat Rant, by Joy Nash, a proponent of the fat acceptance movement. As we sat around the coffee table with wine and hummus, I mentioned having watched the video, and before I knew it, we were discussing the prejudice fat people deal with every day and how a person's weight is nobody's business but her own. It felt surreal to be able to talk to Jess about weight this way, and to hear her and Dan call themselves fat without flinching.

"Would you rather weigh less than you do?" I finally dared to ask. My husband stared at me wide-eyed, sure that this time I had really gone too far.

Jess thought about it. Dan thought about it. And their answer was, essentially, no.

A few months later, Jess and I went shopping at a plus-size store in Brooklyn— so much hipper than the store of my nightmare—to look for a wedding dress. After trying on a few, Jess decided she also needed a new bra and jeans. How many mothers and their daughters can go jeans shopping together without a dressing room meltdown? Amazingly, we could.

After seeing the Fat Rant video, I'd steeped myself in fat acceptance blogs and had finally become able to accept that Jess was not only fat but beautiful. Her weight was no longer the first thing I saw, or fretted about, or even thought about, when I was with my brilliant, funny, sexy, sensitive daughter. We seemed to have crossed some significant barrier.

But there's a catch: As much as I can embrace fat acceptance for Jess and Dan and their friends, I still can't embrace it for myself. The thought of letting go and just weighing whatever I'm destined to, no matter how much—well, it's scary. I think this bothers Jess. I think it interferes with our ability to be completely candid when talking about weight—but I can't help it. I'm just not there yet.

Oh, but Jess—she's there, emphatically so. That skilled, self-confident shimmy I watched at her belly dance recital did not come easily, but come it did, and it was a lovely thing to behold. That's the image that comes to me when I think about Jess's weight: her body in motion that evening, with a grace and a beauty I had never seen before. It didn't bother me that the midriff she exposed was fat. It didn't bother me because it so clearly didn't bother her.

Robin Marantz Henig is a freelance science writer based in New York.