Marie Osmond seems to be winning the battle of the bulge. The 57-year-old singer and entertainer says she’s lost 50 pounds using Nutrisystem and has been able to keep the weight off during her 10 years as a spokesperson for the weight-loss product company.

“Nutrisystem taught me how to eat, so my body loved me back,” Osmond tells me in the video above. She still eats foods she loves like pasta and chocolate, but says she’s learned portion control and eats smaller meals more often, about six times a day. “I’m not desperately running to have a candy bar,” she says.

Osmond admits she’s always struggled with her weight, even as a 14-year-old girl starring in a popular weekly variety show with her brother, Donny Osmond, in the late 1970s.

“It was the era of lollipop heads and twiggy bodies, and you just don’t treat your body right,” says Osmond, who just renewed her Las Vegas show with Donny for a ninth year at the Flamingo Hotel.

“When you’re overweight, you’re overwhelmed,” explains Osmond, who says she’s had success with Nutrisystem because she doesn’t have to weigh in, measure food or count points.

That seems to be a direct jab at Weight Watchers, the rival diet-plan company that Osmond’s friend Oprah Winfrey bought 10% of in 2015. Winfrey has been seen in advertisements flaunting her 42-pound weight loss on Weight Watchers, while toasting a glass of wine.

“Everybody’s trying to get into whatever works for whomever,” Osmond says of Winfrey’s Weight Watchers connection. But, she adds, “To me, toasting a glass of wine, there’s a lot of sugar in that glass.”

While Winfrey’s involvement with Weight Watchers has helped fatten the company’s flailing stock price, Nutrisystem continues to outperform its rival. Over the past 12 months, Weight Watchers stock is down more than 50%, while Nutrisystem’s stock is up more than 60% during the same period.

Osmond says she was a customer of Nutrisystem long before becoming a spokesperson for the brand. “I actually bought it and started losing my weight. Nutrisystem found out about it and asked if I would endorse [the product].”

Well, get ready to see a lot more of Osmond. She’s currently featured in Nutrisystem’s new ad campaign called Lean 13, which promises customers they’ll lose up to 7 inches and 13 pounds in their first month.

“The best predictor of long term weight loss is short term weight loss, so the program allows people to have fast success, and they tend to continue on,” Nutrisystem CEO Dawn Zier says.

Zier says the trend towards locally sourced, whole grain, unprocessed foods has resulted in changes at the company. “Over the past 18 months, we’ve eliminated artificial flavors, sweeteners and colors from our products, and most of our foods don’t have artificial preservatives.”

Nutrisystem is also re-launching the South Beach Diet, which it bought for 15 million dollars in 2015. “The first phase of that diet is gluten-free,” says Zier.

As for Osmond, she says she continues to work on maintaining her weight. For her New Year’s resolution, the mother of eight says she’s vowed to find time each day to take a walk with her husband, Stephen Craig. Osmond first married Craig in 1982, they divorced three years later, and remarried in 2007.