Oprah Winfrey has revealed she turned to a controversial weight-loss drug after realising obesity was a “disease” and not about having a lack of willpower.

The former TV talk show host spoke about her years-long struggle with weight in an exclusive interview with People.

“It was public sport to make fun of me for 25 years,” Winfrey told the magazine for its cover story.

“I have been blamed and shamed, and I blamed and shamed myself.”

Winfrey, who turns 70 next month, said she is now using a holistic approach to diet that includes regular exercise, such as hiking, and other lifestyle tweaks.

“I eat my last meal at 4 o’clock, drink a gallon of water a day, and use the WeightWatchers principles of counting points,” she said.

She confirmed she had also added a weight-loss medication to her regimen.

The turning point came in July during a taped panel conversation with weight loss experts and clinicians for Oprah Daily’s Life You Want series.

“I had the biggest aha along with many people in that audience,” she said.

“I realised I’d been blaming myself all these years for being overweight, and I have a predisposition that no amount of willpower is going to control.

“Obesity is a disease. It’s not about willpower — it’s about the brain.”

Winfrey told People she “released my own shame about it” and consulted her doctor, who prescribed a weight-loss medication.

“I now use it as I feel I need it, as a tool to manage not yo-yoing,” she said, not naming the specific drug.

“The fact that there’s a medically approved prescription for managing weight and staying healthier, in my lifetime, feels like relief, like redemption, like a gift, and not something to hide behind and once again be ridiculed for.

I’m absolutely done with the shaming from other people and particularly myself.”

Drugs such as Ozempic and Wegovy shot into public consciousness as an effective weight-loss medication last year, thanks to spruiking from social media influencers and people such as Elon Musk.

The unexpected increase in demand for the drug for weight loss caused a world-wide shortage.

Semaglutide (in the form of Ozempic) is an effective medication in managing type 2 diabetes – and the shortage has left some people with diabetes struggling to find pharmacies with their treatment in stock.

For many people with diabetes, Ozempic has controlled their blood sugar (and often also helped them lose weight) more effectively than other medications.

Due to the shortage of Ozempic, Australian GPs have been advised against prescribing it to treat obesity.

-with AAP