These days, they're still rocking as hard as ever - in part because Ann is in the best shape she's been in almost 20 years.
"My knees no longer hurt. My low back no longer hurts. I can move around," says Ann, 53. "I'm a physical singer, so it's starting to really make a difference."
Over the years, she had tried numerous diets without success.
Her solution was weight loss surgery - not the gastric bypass made famous by singer Carnie Wilson and weatherman Al Roker - but a new, much less drastic procedure called lap band surgery. Correspondent Troy Roberts reports.
Ann's struggle with her weight began as a child. She was 10 pounds at birth, and became an overweight teenager.
She says she was lucky because she found music, which, she says, allowed her to escape the pain of being overweight.
"That was my best survival world to get into," she says. "A place to go where things were beautiful for you."
But being an overweight as a rock star wasn't easy either. When Heart shot to stardom in the mid-1970s, Ann struggled to fit into the role.
"All through the years, when people thought that I was not a thin, but a normal looking person, I was fasting. A lot - and getting a lot of positive reinforcement for it. How screwed up is that," says Ann, who started eating more and putting on weight.
Ann's struggle with her weight couldn't have happened at a worse time. Appearance has always mattered in show business, but with the advent of MTV and music videos, the emphasis on a band's look became just as important as the music itself. A heavy female rock star wasn't just bad for the band's image, it was also bad for business.
She says she was under constant pressure to lose weight. Many people also told her that her career depended on her losing weight.
To disguise her size, stylists dressed Ann in ways that hid her weight. In some videos, only her face was seen, in tight close ups. Other times, she was obscured in shadow, or hidden behind a barely clothed Nancy. They even used a compression process that stretches the picture to make Ann appear slimmer.
"I was surrounded by all of these people who had undermined my confidence," says Ann. "And who had said, 'Believe you, me, you really don't wannna be seen full body, OK?'"
"I think there was pressure to be more perfect than she felt like she could be," says Ann's sister Nancy, 49. "I think she got paralyzed inside the fear of dealing with it."
As Heart was selling millions of records, Ann was battling severe stage fright and panic attacks caused by the focus on her weight.
In January 2001, after years of failed attempts at losing weight, Wilson finally took the ultimate step that changed her life: weight-loss surgery.
According to lap manufacturer INAMED Corporation, as of July 2003, more than 12,000 lap band procedures have been performed in the U.S. - 110,000 worldwide.
Unlike gastric bypass surgery, there's no cutting out part of the stomach or rerouting of the intestines. Instead, it all happens through five tiny incisions, and a silicon band which is wrapped around the stomach like a belt - restricting the amount of food a patient can eat.
"It turns the stomach into an hourglass shape. So when you eat, the top part of the hourglass receives the food. And of course it's much smaller than before. So you receive the 'I'm full' signal way sooner," says Ann, who found gastric bypass surgery a bit too radical. In fact, statistics show that 1 out of 200 people die as a result of gastric bypass.
"I've seen a lot of early success in my patients," says Dr. Brian Quebbeman, Ann's surgeon. Most doctors, like Quebbeman, say the minimally invasive lap band is the safest weight-loss procedure available - and unlike the gastric bypass, it's easily reversible.
Quebbeman thinks Ann can lose up to 70 percent of her excess body weight with the lap band: "Very few people will lose all their excess body weight. It's just not realistic. So 50, 60, 70 percent – that's a reasonable goal."
Ann's surgery was paid for by Spotlight Health, a marketing company that hired her to bring attention to the lap band. She knows that some will question how honest she can be about her experience, but she says "they just have to look into my eyes and they have to see what I'm saying it true, that's all."
Not everyone, however, is so happy with the results. Faye King, 37, an office administrator in Greenville, N.C., weighed 296 pounds before having lap band surgery in 1999. She says it was her last resort.
Faye was part of the clinical trials and initially she was a success story, losing almost 100 pounds. But two years after the surgery, Faye began suffering from debilitating heartburn and digestive problems.
"I never even had reflux or heartburn until I had the surgery," she says. "Never even knew what it was." Now, she is up several times a night getting ill.
Dr. Ken Macdonald, Faye's surgeon, and one of the first doctors to test the lap band, thought the band had promise. But now, he's concerned about potential complications such as infections and digestive problems.
Even lap band advocates acknowledge that patients with the band lose significantly less weight than those who have the gastric bypass. In fact,
Macdonald no longer recommends the procedure for morbidly obese people.
Macdonald removed the saline out of the band, in hopes that it would eliminate Faye's problem. Since 48 Hours first aired this broadcast last November, Faye decided to get the lap band removed and have the more invasive gastric bypass surgery.
But for Ann and many other severely overweight people who wouldn't consider more radical surgery and have not had any complications, the lap band has dramatically changed their lives.
"This is a work in progress. I feel successful, but I don't feel finished by any means. I have a ways to go," says Ann, who's confident she'll reach her goal of losing 100 pounds.
"I've reclaimed some physical freedom that I lost there for awhile," she says. "It's a wonderful feeling."