I don't know that Judy, and of course it seems quite likely that she is doing this to herself by what you wrote. However, putting on weight doesn't just happen overnight. And it doesn't happen to everyone. The main issue nowadays is that more than 70% of all people lack iodine in their bodies. And I am not talking about the nasty iodine that's added to table salt either. Some people have a healthy metabolism (or what some would call fast) and others (the majority) don't, because of this lack.
Again: eating habits have something to do with it of course, but there are also people (we all know at least one of those) who can eat pretty much anything and never gain as much as a gram.

The issue of weight gain is often coming from other underlying issues. Someone with a lot of weight, is often times depressed, unhappy with something or life in general, or other issues. By thinking that everyone responds the same to 'the truth' you could do more damage. It worked for you when someone said you had gotten fat, but not everyone is the same. Most people (if not all) who are overweight know that they are. They don't need anyone to tell them. In fact, I know many people who would do quite the opposite when someone would tell them they're fat.
A lot of people use food as an escape. It makes them feel good.
So if someone would tell them they're fat, they might just nod, go home and indulge in some ice-cream to make them feel better. Of course, only to feel worse after...

My personal story: I always thought I was fat when I wasn't. When I look at pictures of myself, or when I found some old clothes from that time, I would always think: 'What the hell was I thinking? I fit in those?' When I fell pregnant with my eldest, my relationship with my husband went from 'not perfect' to downright bad. I left him when I was three months pregnant. I only gained about 10 kg. of weight throughout my pregnancy and this was pretty much all gone right after the birth. But then there I was: alone with my child, and this was so much different from how I would have expected it or wanted it. I fell into a deep depression and to be honest, she saved my life. I felt abandoned and alone, even though I had her, and it all began when I would buy snacks for visitors that didn't come as frequently as I would have hoped. I used food as an escape. Within a year I gained 35 kg.
I was going to the gym, but the eating habits only slowly changed. Then one day, I weighed myself, and saw that the scales went over 100 kg.! That, to me, was my rock bottom. I told myself: this is it, I'm done, I have to change. It wasn't anyone else who pushed me. It was me.
I started going to the gym 3 to 5 times a week, and if I didn't go, I felt rotten. Addicted to the gym is still better than addicted to food though.

Then one day, I was going a really intensive group training that I loved and had been doing for months, twice a week. An old 'friend' and colleague from my college years walked in with his colleague. They were both cops. He greeted me, and then turned to his friend and said something and laughed. He thought I hadn't seen it, but I knew he had made a remark about me and how much weight I had gained. Now, not long before this, this would have sent me home nearly in tears and binge eating. But this time, I knew he was an ignorant ass and I turned to start the training.
And guess what? Within 10 minutes, this guy had his tongue on his knees and his face was bright red. He couldn't keep up!
That made me feel a bit better about myself since I had no issues.
Halfway in the hour, the two of them left, exhausted. Now, that made me laugh. I might have still been overweight, but I sure as hell was a lot fitter than two police officers who should be fit as a standard.
So yes, diet is important, but personally I believe that once someone starts a workout routine, the food will follow. When I look at myself: when I am very active, I tend to slowly start eating healthier. If I work out more, I even start to dislike fatty foods and sugar. Somehow the body regulates this. I mean, people can eat a healthy salad and do a work-out an hour later. But if you shove down a big bowl of spaghetti bolognese it's a completely different story, isn't it?
Now, with that ex-colleague, if all people would react like you, they would all have that wake-up call and go do something about their weight. In my case, it would have been the opposite.

It's like telling a smoker that it's an unhealthy habit to smoke. I believe we all know this without being told. In fact: tell a smoker he has a bad habit, and he will nod and light another cigarette...

And if Judy has good friends, or at least one, I'd say it would do more good if they would try to find out what's really bothering her. Maybe spend time with her. Or even suggest finding help outside of her friends. But telling her she's fat, could possibly do more harm than good. If she's like me, it definitely will.