What is the secret to longevity? This question taunts all of humanity.

Although we have yet to discover a fountain of youth, centenarians – individuals who live to be over 100-years-old – can potentially give us clues on to how to live longer, healthier and happier lives. By taking a closer look at their lifestyles, genetics and social dynamics, some scientists are trying to find patterns that can show us their secrets.

At the same time, if you ask the centenarians themselves, they often give answers ranging from the seemingly logical to the downright bizarre.

Here are five unusual things centenarians have given credit for their long lives.

1. Sumo wrestling and hot springs

Just this week, Guinness World Records crowned Masazo Nonaka as the world's oldest living man. At 112, the elderly Japanese man was born all the way back in 1905. That means he would have turned nine the year that World War I began.

Although he moves around in a wheelchair, Nonaka reads the newspaper every morning and feeds himself breakfast. As to the secret to his long life? Well, the centenarian soaks regularly in northern Japan's hot springs and considers watching sumo wrestling to be one of his favorite pastimes.

2. Humor and chocolate

Jeanne Louise Calment of France still holds the Guinness record as the world's oldest living person. She died at the impressive age of 122 years and 164 days in 1997. Having definitely lived a full life, Calment sold painting canvasses to Vincent Van Gogh, smoked from the age of 21 to 117 and even became a recording artist at 120-years-old.

Calment accredited her longevity to her sense of humor. When she turned 120, journalists asked her what kind of future she expected. She replied quickly: "A very short one." Also an avid lover of chocolate, Calment reportedly consumed about 1 kilogram (2 pounds 3 ounces) of the stuff each week.

3. Eating less

Currently holding the record as the man to live the longest, Jiroemon Kimura of Japan lived to be 116 years and 54 days. He died in June of 2013.

Born in 1897, Kimura worked at the post office until he retired at the age of 65. He then went on to live more than another half a century.

And what was his secret? According to him, eating less was the key. He reportedly said that his personal motto was: "eat light to live long". Notably, Kimura's philosophy has increasing support among the scientific community.

Many scientists and nutritionists believe that a 30 percent reduction in daily calorie intake may significantly slow down the physical processes that make cells heal slower, which opens up the brain and body to disease. Studies have also shown that calorie restrictive diets in mice help combat the effects of aging on the brain.

If the scientists – and Kimura – are right, cutting down on your daily consumption can help you shed a few pounds while also keeping you young.

4. Eat everything ... except pork and chicken

In July of last year, Violet Moss-Brown of Jamaica became the oldest living woman and the oldest living person. She claimed both titles at the age 117 years and 139 days old. A few months later, she died, proud to know that she had claimed both world records.

When asked about her secrets to long life, Moss-Brown suggested there wasn't much to it. However, she did say she never ate pork or chicken.

"When people ask what I eat and drink to live so long, I say to them that I eat everything, except pork and chicken," she told Guinness.

5. Smoking cigarettes

Batuli Lamichhane, who was reportedly 112 in 2016, claimed that her secret to long life was smoking cigarettes.

Born in March 1903, Lamichhane started smoking when she was 17. The centenarian told The Mirror that she smoked some 30 cigarettes a day for the past 95 years.

"I have been smoking for over 95 years. There is nothing wrong with smoking," she said.

But before you rush out to buy a pack of cigarettes, remember that any doctor or scientist will explain to you that smoking significantly increases your risk of heart disease, cancer and a range of other health issues.