The oldest woman to compete in Miss Texas USA is 72. She avoids cheese and processed meat — but loves a good steak.

The retired teacher and grandmother also lifts weights three times a week, and does cardio on the other days.

• Marissa Teijo, 72, made history last month for being the oldest woman to compete in Miss Texas USA.
• Teijo told People she lifts weights three times a week and doesn't eat cheese, processed meats, or white bread.
• Her best advice for keeping healthy? Don't stop moving, she says.

With her youthful looks and toned abs, it's hard to tell that Marissa Teijo, 72, made history last month as the oldest woman to compete in the Miss Texas USA competition.

The key to her ageless beauty? A clean diet and regular exercise.

In an interview with People published on Tuesday, Teijo, a retired teacher and grandmother, spoke about her eating habits and fitness routine.

"I eat very, very clean and healthy. My nutrition is mostly a lot of vegetables and a lot of fruits, oatmeal," Teijo told People. "I don't eat cheeses. I don't eat processed meats. I do not eat white bread; I only drink non-dairy milk."

She also said she occasionally eats meat, such as chicken and fish, and loves a good steak, she said.

"But I do indulge every once in a while. I try to eat cookies that are made with almond flour and very little sugar," she added.

While training for the Miss Texas USA pageant — which took place in Houston on June 21 and 22 — Teijo said she kept to a very strict diet because she "wanted to be as fit as possible."

"On my training days, I would eat sweet potato and jasmine rice or brown rice and oatmeal, and then lots of vegetables at every meal, lots and lots of vegetables and fruits too," Teijo said, adding that she even cut sugar from her diet.

On days when she wasn't training or weightlifting, she wouldn't eat any carbs at all, she said.

"I would just eat protein, fruits and almonds. That was a little bit more stringent, but it wasn't for a long time," Teijo said. "I did that for about two and a half months; I don't recommend that long term."

As for her workouts, Teijo says she does weightlifting three times a week and does cardio on the other days.

"I either go spinning or walk my dog up and down the hills here where I live," she said.

Teijo says she started weightlifting when she was 40 and used to do it five or six days a week before cutting it down as she got older.

"I was always a runner, and I would do step aerobics classes. But when I started weightlifting, that's when my body evolution started," Teijo said. "Weightlifting will give you the best shape; it looked like I had a very small waist, because you gain muscles in your upper body, so you get that hourglass look."

But what matters most is keeping active, she said.

"I don't stop. And that's one of the things that I would highly recommend to anybody: Just don't stop. Because no matter how old you are, you can still move. And if you keep on moving, you'll be able to move the older you get," she said.

Although Aarieanna Ware, 26 — last year's Miss Dallas winner — won the Miss Texas USA title, Teijo told ABC News El Paso affiliate KVIA that she hopes she can inspire others to be confident.

"I hope that people will look at us as older women as still being beautiful in our own way," Teijo said.

Research has shown that a combination of weightlifting and cardio can improve longevity.

And there's no need to spend hours at the gym: Just 30 minutes of muscle-building workouts a week can lead to a 10% to 20% lower risk of dying from illnesses like cancer or heart disease.

Blue Zones — a term popularized by Dan Buettner, a journalist and researcher — are regions in the world where people live longer and healthier lives. In these places, people tend to consume a diet that's high in fiber, including foods such as beans, nuts, and whole grains.

Loma Linda, California, was the only US destination to make it on Buettner's original Blue Zone list in the early 2000s. Since then, projects encouraging similar lifestyles have been launched across the country, including one in Fort Worth, Texas.

Representatives for Teijo and Miss Texas USA did not immediately respond to a request for comment sent outside regular business hours.