For years, health experts have urged that the key to living a long and happy life is following a healthy diet. They've studied the food secrets of the longest-living people and have even identified the "world's healthiest breakfast" for you to copy. But, following a healthy diet also includes what you don't eat.

In a major interview with The New York Times in March 2024, Valter Longo, PhD, a professor of gerontology and biological sciences and the director of the USC Longevity Institute in California, shared the remarkable findings he's learned about longevity by studying his home country of Italy. Here's what Dr. Longo dubs the 5 "poisonous Ps" in your diet, how they could be wrecking your overall health, and what you should be eating instead if you'd like to live to 100 or beyond.

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Dr. Longo believes there's a reason so many people in Italy live to 100. Shutterstock

Italy is known for having one of the world's oldest populations. In fact, the city of Sardinia, Italy, was the first of the five Blue Zones (parts of the world with the most centenarians) to be discovered.

"For studying aging, Italy is just incredible," Dr. Longo, who runs a lab at a cancer institute in Milan, told The New York Times. "It's nirvana."

He grew up in the city of Genoa but often visited his grandparents in Molochio, another part of Italy known for its high number of centenarians. He's dedicated his career to learning how people can age well into the future—and he's personally looking to make it to at least 120 or 130.

"It really makes you paranoid now because everybody’s like, 'Yeah, of course you got to at least to get to 100,'" he said. "You don’t realize how hard it is to get to 100."

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He believes the original Mediterranean diet helps boost longevity. Shutterstock

Hard as it may be to live to 100, Dr. Longo advocates for longer and healthier living by eating a plant- and nut-based diet that he created called "Lite Italian."

"It’s very similar to the original Mediterranean diet, not the present one," Romina Cervigni, PhD, a resident nutritionist at Dr. Longo's private foundation based in Milan, told the NYT.

The original Mediterranean diet consists of plant-based foods, healthy fats (like olive oil), and moderate amounts of fish, dairy, and poultry, with very limited red meat. Whole grains, legumes, fruits, vegetables, and nuts are also staples in the diet.

"Lite Italian" is very similar, Dr. Longo claims. He goes into more detail about his longevity diet on his website.

"Eat mostly vegan, plus a little fish, limiting meals with fish to a maximum of two or three per week," he writes. "Consume beans, chickpeas, green peas, and other legumes as your main source of protein."

He suggests avoiding the 5 "Poisonous Ps." Yulia Grigoryeva / Shutterstock

Unfortunately, the original Mediterranean diet has been lost in recent years, according to Dr. Longo.

"Almost nobody in Italy eats the Mediterranean diet," he told the NYT. Instead, daily meals consist of cured meats, layers of lasagna, and fried vegetables, which Dr. Longo considers to be "horrendous and a source of disease."

He's particularly worried about what Italian children are eating these days—noting that many are battling obesity due to the five "poisonous Ps."

These are:

- Pizza

- Pasta

- Protein

- Potatoes

- Pane (Italian for bread)

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Dr. Longo encourages faux-fasting to get your diet back on track. Shutterstock

To get Italians and other people throughout the world eating healthier, Dr. Longo has released The Longevity Diet, which he describes as a "clinically tested diet program, based on decades of research, to fight disease, maintain an ideal weight, and live a longer and healthier life."

The program focuses on his Lite Italian diet, which you should eat most days, along with four sessions a year that involve a five-day, fasting-like diet with supplements and kale crackers.

The combination of this plant- and nut-based diet with "faux fasting" allows your body's cells to shed harmful baggage and rejuvenate without being starved, Dr. Longo told the NYT.

He encourages adults to also practice intermittent fasting. "Confine all eating to within a twelve-hour period; for example, start after 8 a.m. and end before 8 p.m.," he states on his website. "Don’t eat anything within three to four hours of bedtime."