How do I cope with her negativity in a way that will be healthy for our friendship and for me?
I think you have a good sense of where your friend’s comments are coming from, though I don’t think you have to “cope with her negativity.” You can (and should) address what’s going on between you, but before you do, it will help to go into this conversation with a healthy dose of compassion for her.
It turns out that your friend is having a common reaction—it can be surprisingly hard to see the people closest to us change, even (and especially) if that change is good. This happens all the time in families, where if one person starts to make healthy and positive changes, it’s not unusual for other family members to try to maintain the status quo. If an addict stops drinking, for instance, her husband might unconsciously sabotage his wife’s recovery because to regain homeostasis in the system, somebody has to fill the role of the troubled person. And who wants that role? Similarly, people can resist positive changes in their friends: Why are you going to the gym so much? Why can’t you stay out late—you don’t need more sleep! Why are you working so hard for that promotion? You’re no fun anymore!
This is likely what’s happening with your friend. All of a sudden the balance between you two is out of whack. The person who seemed more in control of her weight (her) now has to face how out of control she really is, because she can no longer focus on your problems as a distraction from hers. (And without that distraction, she must find another way to manage her anxiety, and it’s possible she’s using food to do that.)
But there’s another aspect to this role reversal, one that people often have a hard time talking about: envy. Think about how common it is in everyday situations to be jealous of a spouse or close friend, and how taboo that is to talk about. Aren’t we supposed to be happy for their good fortune? Isn’t that what love is about?
In one couple I saw for therapy, the wife got her dream job on the same day that her husband was let go from his, which made for extreme awkwardness at the dinner table. How much could she share about her days without inadvertently making her husband feel bad? How could he manage his envy without raining on her parade? How noble can we reasonably be expected to be when someone we love gets something we desperately want but can’t have?
Sometimes people aren’t even aware of their envy, because of the shame it tends to travel with. Most of us believe that because we love or care about someone close to us, we should be unconditionally happy for their success, and if we notice any ambivalence at all about it, it often quickly gets repressed. But our envy leaks out anyway—through sabotage, perhaps, or snide comments like the ones your friend has made. What we tend to forget is that envy can be a powerful force for change. During my training, a mentor told us interns to pay attention to our patients’ envy (and our own): Follow your envy—it tells you what you want.