You seem to be missing the point; the best thing to "do" is leave her alone. Give her some space. Stop trying to talk to her about it. While not all women will react the same way, I can tell you that many women would want to be left alone after being insulted like that. They're not looking for an apology or to make up. They need time and space for the hurt to go away. Right now, your presence may feel like a knife to her. Insulting a woman's body is not a small, silly, or little thing. Depending on her life history, this may be the biggest mine field you could have walked into. If you want any chance of her coming around in the future, leave her alone and wait for HER to contact you. Moreover, she is not taking space from you to "get back at you." She is not trying to punish you. She is most likely protecting herself. The absolute last thing most women would want is to be reminded of the hurtful comment by having you continue to bring it up or even apologize for it. That is like inflicting the wound all over again. If she values your friendship, she may come back in time after the pain isn't so fresh. If you were just a casual friend, she may not. But this isn't on her; she didn't do something to you. You insulted her in a way that would be excruciatingly painful to most women. Learn a lesson from it. NEVER comment on a woman's weight. Ever. That is a sure fire way to inflict horrible pain, because it triggers decades of other such memories and insecurity and self-esteem issues.