Barbara Fedida, highest ranking woman at ABC News, referred Johnson to a stylist and said she did not look as good as she could. Never was the word "fat" used, but Johnson clearly "heard" her saying: Lose weight or lose your job.
"I loved my job. She spoke to me in the most gracious polite and respectful manner," Johnson said in an interview with AOL Jobs. "She didn't make a threat and there was no timetable. When you're asking someone to change, change takes time."
Since that conversation, Johnson has dropped more than 70 pounds and wrote a book about it: "The Shift, How I Finally Lost Weight and Discovered A Happier Life." She dedicates the book to Fedida.
How has being thinner changed the way you work?
"You know, it's definitely made me happier. More visible. More energetic. I give more of myself. I sort of hid behind my weight in a lot of ways. I'd turn down invitations to events. Instantly I'd think I don't have anything to wear to that."
What the story reveals is that difficult workplace conversations can have more impact than those with a friend, a spouse, a child, even a doctor. "It opened up an opportunity for me to be honest with myself," Johnson says.
"I had been the person who tried and failed for years and years and years to lose weight. It was the classic weight battle. Classic yoyo dieting. This conversation finally freed me to just realize I was fed up with being fed up and I was going to do something about it for once and for all."
Workplace conversations can have more impact than any others. But for this to work, Johnson maintains, you have to really love your job and value your job enough to hear what someone has to say. It requires some mutual respect for the person who delivers any kind of news about your appearance.
What made Fedida's message so receivable, Johnson says, was that "She never threatened my job. She never said, 'You're fat. Lose weight.' I do very much believe her that my job wasn't in jeopardy.
"Someone who hates their job would hear that and say, 'What, are you on crack?' "
What is relevant to anyone who has to have a difficult workplace conversation -– whether it's a nurse, a salesperson, a teacher, is that Fedida offered a solution.
"Instead of saying, 'You don't look your best, what are you going to do about it? she offered a solution. Send me to a stylist."
Johnson's book was an instant New York Times bestseller since its release in September.
"Why did this conversation work so well for me? There was never a part of me that was upset. I couldn't be upset. The way she did this was so perfect. So unbelievably gracious there was no opportunity for me to be upset. Only a chance to better my life. That's essential in a difficult workplace conversation."
Johnson, who is 43, has worked at "Good Morning America" for seven years and says the experience taught her the value of not just dumping a problem on someone to solve, but instead to suggest a solution and an offer to help.
What else has changed?
"I jog in Central Park. I'm the girl who was always picked last on teams in elementary school and middle school. Now I jog with my kids and husband. I do 30 to 45 minutes on a treadmill. I go to a gym every week. Exercise is a big thing. It's an overall feeling of happiness.
"When this conversation happened and opened the floodgates, I had to admit I didn't go to the doctor for more than 10 years because I didn't want a lecture about my weight. When I hit the one-year mark, I went to the doctor and got my first mammogram. After avoiding it for more than 10 years, that's a great moment to have a doctor say, 'You're doing great.' That is a really happy freeing moment I wouldn't have gotten to if not for Barbara's conversation."
Rather than try another diet, Johnson says she lost the weight by choosing behaviors that can last a lifetime: Eat less. Choose better. No cheat days. Move more. Hold herself accountable daily. Pause before binging. Keeping the priority on losing weight always allowed her to make the right choice.
Looking better on TV was the lesser benefit, Johnson says. So many GMA viewers started writing to her that it motivated her to write the book. "Talking about these things shouldn't be embarrassing," she said. "I'm not a doctor/trainer/nutritionist. I'm an ordinary person."
Have you earned more money since losing weight?
"Yes because I say Yes more often to things. I say Yes to speaking engagements that I might have said no to ordinarily. I network more. I'm more visible, so I've had a lot more opportunity come my way."