Elaine LaLanne is spending the days since her 100th birthday with the same healthy habits she’s been cultivating for decades: exercising every day and eating a nutritious diet.

She starts each morning with abdominal exercises, leg lifts and and pushups, noting she’s “very strong in the core.”

The widow of famed fitness guru Jack LaLanne credits her husband for turning her life around. He hosted the first TV exercise show starting in the 1950s and has been called the “father of the modern fitness movement.”

She recalls initially dismissing him as “this muscle man” when they first met in 1951 — LaLanne booked him to perform pushups during a TV program she was producing — but becoming intrigued by his healthy lifestyle.

“I wouldn’t be here today if I hadn’t met Jack LaLanne. I was always eating chocolate donuts and smoking cigarettes and eating candy bars for lunch,” the centenarian, who lives in California, tells TODAY.com.

“He told me, ‘You should be eating apples and bananas and oranges.’ I said, ‘Are you kidding?’ Then I changed my tune, and I’ve been a convert ever since. I know that’s why I lived to be 100.”

She stopped smoking, started eating healthier and began exercising. The couple married in 1959. She says most women didn’t work out in those days, but the “The Jack LaLanne Show” got many female viewers interested in exercise.

Elaine LaLanne was a regular part of the program, and became an author and public speaker, touting the benefits of exercise and good nutrition and earning the nickname “The first lady of fitness.”

She was married to Jack LaLanne until his death at 96 in 2011.

The Health & Fitness Association inducted the couple into its Hall of Fame in March.

Here are Elaine LaLanne’s simple tips for living a long and healthy life:

Exercise Every Day

The centenarian has been exercising daily for most of her life.

At 100, before LaLanne gets out of bed, she still does 20 “jackknife” ab exercises every day, a routine she’s followed for years. The core workout involves starting in a lying position, then lifting the torso and legs at the same time, ending up in a V-shaped position.

She also does leg lifts and other leg exercises while lying down, then gets up to do pushups against a wall or sink.

When LaLanne was younger, she used to be able to do 50 full-body pushups. She also worked out with weights and used a treadmill. Her workout sessions usually lasted 30 minutes.

Swimming was another favorite form of exercise. “Jack said swimming is probably one of the best all over exercises one can do,” she notes. Swimming is one of the best sports for a long healthy life, studies confirm.

Eat a Healthy Diet

LaLanne doesn’t follow any particular eating plan, like the Mediterranean diet or a low-carb diet. She calls her approach “just plain old watching what you want to put in your mouth.”

When you eat, ask yourself: “What is this going to do for me?” she advises.

Her typical breakfast might be yogurt mixed with protein powder and topped with blueberries, strawberries and other fruit. She’s never been a coffee drinker, so she prefers to have a cup of cocoa. Cocoa has antioxidant properties, enhances cognition and boosts positive mood, studies have found.

For dinner, she loves to eat salmon or chicken, but otherwise doesn’t consume a lot of meat. The rest of her plate is filled with a lot of vegetables, plus rice or potatoes.

“I love potatoes. I grew up in the Midwest, and I’m still a potato lover,” she says. “It’s just simple, simple things. I eat like most people.”

She eats just enough so that her stomach is full without overindulging.

Live Life in Moderation

Her husband was extremely disciplined and didn’t eat dessert, opting for fruit and figs to satisfy any sugar cravings.

She followed suit and didn’t have any cake or ice cream for decades, but then rebelled.

“I said, ‘Jack, I’m 80 years old, and if I want a piece of cake, I want to have a piece of cake,’” she recalled.

“One candy bar is not going to kill you. … When you overindulge, that’s the downfall. And if you just have a little of this, a little of that, it’s not going to kill you. That’s what I believe.”

She has the same approach to alcohol, enjoying an occasional glass of wine.

Be Consistent

Jack LaLanne said, “It’s not what you do some of the time that counts. It’s what you do most of the time,” his wife points out.

She sums up her own philosophy as the acronym ARCH.

• A for attitude.
• R for resistance — “If you resist that muscle, it’s going to work for you. If you resist the food that’s undermining your health, you’re going to be healthier,” she says.
• C for consistency.
• H for harmony.

Think Positive

“I’m a very positive person, and I don’t let anything bother me,” LaLanne says.

“If people could get rid of negativity, they would be a lot happier.”

Her husband encouraged that mindset, always reminding the family, “We do not talk negative in this house,” she recalls. He was also a believer in visualizing a positive outcome before it happened.

Accept and Persevere

When LaLanne’s 21-year-old daughter died in a car accident, she got through the tragedy by telling herself she couldn’t change things, so she had to accept what had happened.

“Just before I turned 100, I was thinking, how can I sum this whole thing up in all my life? I thought about my acceptance,” LaLanne says.

“Through my life, I’ve accepted what I’m handed, and then I persevere. … Those two things are my mantra.”

She’s still applying that mantra today as she deals with macular degeneration that’s caused her to lose sight in one eye. LaLanne accepts her worsening vision but looks for ways to work around it. She can still see her computer screen and keep writing, so she perseveres.