STYLETHREAD -- LET'S TALK SHOP!

It's hard to say without knowing your friend. Personally, I would react very badly, and would in fact probably eat more (it's a perverse reaction, but it has to do with binge eating problems and all that). Anyway, I find it hard to believe your friend isn't already aware of her weight gain, and probably feels self conscious about it. I think I would just bring up the subject of exercise/healthy eating in a general way (for example, "Hey, I just tried the best recipe the other day, and I was amazed it was so healthy, since it tasted so good. I've really been trying to eat better lately, and I have so much more energy." Something along those lines). That way she doesn't feel like it's attacking/directed at her, but it gives her an opening to discuss those things if she's been wanting to. My sister is overweight, and has been for many years, but needed to come to the decision and resolve on her own to lose the weight and make a lifestyle change. Now that she has, I'm 150% supporting her. But before she made that decision, she wasn't willing to discuss her weight/body issues.

You shouldn't say anything. It's her life, and you can't tell her what to do. She probably won't listen anyway and instead will be really offended you said anything. I don't think it's worth ruining the friendship. Also If she finds out you guys are talking about her weight behind her back, she'll probably be pretty upset/mad.