I ballooned up (hah! ballooned.. I went from 150 to 164 lbs) which was visibly a lot of fat to have hanging around on my body. It was because I got insanely depressed. Hair started thinning out, really badly. It felt like it was useless to bother to get better, why bother, I'm depressed and food comforts me.

Then I realized, what comforts me more than food is confidence. So I sought help. Ironically, on my way to register at the gym, a herbalife guy caught me and offered me free samples. And holy shit. The way it made me feel after their three drink thing, it was energy I hadn't felt in ages. All the energy drinks and stimulants never did shit, but those drinks were healthy as fuck - soy shake, tea, and aloe water. It just hit me right then after I had them. I was bouncing off the walls, felt great. Within literally weeks I dropped the excess weight and felt amazing. For me, it was really easy. I like instant satisfaction as a lot of people do.

But in a more extreme case, a hundred pounds overweight, things like that, the instant satisfaction simply will not happen. OP had it right, nothing is going to happen if the person in need decides to change on their own. You can convince and push them to try, but it ultimately has to be their decision, just as with any addict. For this its something that hit me and I've seen works on others: You have to have a reason to do it. And that's the hard part. There has to be a goal, a light at the end of the tunnel. And until you stop pitying the fuck out of yourself and turning to your comfort tools, food - drugs - laziness - misery - anything non constructive, you will get nowhere. Honestly? I don't know why you even care about her condishun. But if it's really something you want to take care of, lie to her and tell her you were just like her once and you got out of it, tell her how you did it, give her food ideas that are awesome and timeframes of expected results, give her resources that sound appealing, not demeaning or depressing.

My secret tool when I dropped my excess weight was, go figure, Chipotle. God damn. Rice and beans are your fucking friend. And some exercise, and of course, dodging greasy garbage and foods with excess preservatives. It doesn't have to be all "Eat carrots!" to lose weight. But reduction in bad behaviors will show nearly instant results, and those results no matter how little are what you have to cling to and struggle for. This is why so many successful dieters take before and after pictures. They're fucking major in self motivation, and emphasis on it being okay to fall off the wagon from time to time is important. People like to fuck up and say "welp, I fucked up, guess it's over". Never quit trying, just keep going, even after a few weeks of dieting hard and cheating in a bucket of icecream? It was a mistake, but the struggle isn't over there.

Good luck, you're gonna need it. Odds are if you push too hard, she'll resent you, because as we're here on FPH to mock, these people don't want to accept they have a problem, they want to believe you not accepting them is the problem.