Actor and director Rob Lowe decided to change his diet when he was in his 30s and swore to stuck with it for 20 years.

The 57-year-old recently told Insider, “Everyone comes to the point sooner or later where you realize you can’t eat like you’re in college anymore. I hadn’t realized it was a thing, but it changed my life.”

Lowe planned to give a low-carb diet a try and he has been following it for the last 20 years. He mainly focuses on having lean meats, fish, and tons of fruits and vegetables.

The diet has worked so well for him that he is now a spokesperson for the Atkins diet – the low-carb, high-protein, diet.

The Parks and Recreation actor explained, “This way of eating gives me way more energy during the day. I’m not tired after a meal, I’m more focused and it enables me to train harder. It also keeps my weight down even though I don’t use it as a diet.”

Lowe also said that he does cheat and loves his sweets, adding he will happily go off-plan to get in his favorite treats, according to PEOPLE.

“I love to cheat,” he said. “I love pizza and I love cheeseburgers, and ice cream and nachos. Life without that stuff isn’t worth living. It’s about moderating it and doing it in a healthy sustainable way.”

“When you have willpower, use it,” Lowe continued. “We all have willpower sometimes. And then there will be days when you say ‘gimme those nachos and put them in my body.’”

Overall, Lowe follows a simple mantra: sticking to the right foods and avoiding wrong foods. “I know enough to know if I stick to the right foods and avoid the wrong foods, I’m going to be fine,” he said.

In 2018, Lowe told PEOPLE that his diet and exercise routine has played a key role in maintaining his career.

At the time, he said, “I have to take care of myself and be disciplined. I have to get enough sleep, work out, eat right. I look at myself as no different than a professional athlete.” “If you go to sleep on it,” he added, “you can’t expect to have the energy to be diverse and have longevity.”