What Is the Longevity Diet?

The longevity diet is a set of guidelines for healthy eating developed by biochemist Valter Longo, Ph.D., director of the USC Longevity Institute at the USC Leonard Davis School of Gerontology. It is meant to help people live longer, healthier lives. The longevity diet recommends following a plant-based diet that includes little-to-no meat and poultry and periodic fasting.

Although there are known benefits to eating a diet rich in vegetables and whole grains, there has been limited research into how diet can affect longevity in human beings. Because the diet also involves periods of fasting, it may not be right for people who have a history of disordered eating. More research is needed before this diet can be recommended as a way to increase your lifespan.

This article discusses the longevity diet, its purported benefits, and whether or not the research shows that it can increase human lifespan.

How to Follow the Longevity Diet

The longevity diet resembles a modified vegan diet in which certain seafood and small amounts of meat and dairy are allowed. It is as much a lifestyle as an eating plan and can be followed for an indefinite amount of time. The guidelines include following a five-day fasting-mimicking diet periodically throughout the year.

What to Eat

The majority of foods comprising the longevity diet food list are plant-based, including:

• Leafy greens like chard, spinach
• Fiber-rich vegetables
• Fresh fruits of all kinds
• Beans and legumes (chickpeas and lentils)
• Nuts

The diet also allows small amounts of low-mercury seafood, including shrimp, salmon, and tilapia.

Olive oil, which is used liberally in the Mediterranean countries where many of the tenets of the longevity diet originate, is a staple in the longevity diet. High in omega-3s, it's also a versatile cooking oil that works well as a dressing, marinade, and even in some baked goods.

There are no hard-and-fast rules regarding food preparation on the longevity diet, although it's best to use low-fat cooking methods such as steaming, grilling, and sauteeing rather than frying.

What to Avoid

The longevity diet advises avoiding meat, poultry, and dairy products, as these foods are high in saturated fat. If completely cutting out meat and poultry isn't doable, the recommendation is to limit them as much as possible by including them in small quantities to add flavor to plant-based dishes rather making them the centerpiece of meals.

The longevity diet recommends avoiding dairy products. For those who must have milk and cheese, however, it suggests switching from cow's milk and cheeses to goat's milk, cheeses, and yogurt, which are rich in minerals and have anti-inflammatory benefits.

Intermittent Fasting

All meals and snacks should be taken within a 10-to-12 hour time frame—for example, between 8 a.m. and 6 p.m. to 8 p.m. The guidelines also suggest not eating during the three to four hours before bedtime.

For purposes of meal planning, people who are overweight or tend to put on pounds easily are advised to eat two meals—breakfast and either lunch or dinner—and two low-sugar snacks per day. Those who are at a healthy weight or who lose weight easily are advised to eat three meals a day and one low-sugar snack.

Fasting-Mimicking Diet

People who adhere to the longevity diet also follow an eating plan that mimics fasting several times a year. This involves consuming limited amounts of foods, mainly vegetables, nuts, and seeds, for five days. Total calories for each day range from 800 to 1100, with 60% of calories from fats, 10% from protein, and 30% from carbohydrates.

Claimed Benefits

The main tenets of the longevity diet—eating more plants, less protein, and fasting—are based on Dr. Longo's research of long-lived populations around the world, including in Greece, Italy, and Japan, as well as studies he was involved in in the United States.

One of these, published in October 2016 in JAMA Internal Medicine, assessed the dietary habits and health of more than 130,000 healthcare professionals.

It found that "high animal protein intake was positively associated with cardiovascular mortality and high plant protein intake was inversely associated with all-cause and cardiovascular mortality, especially among individuals with at least one lifestyle risk factor. Substitution of plant protein for animal protein, especially that from processed red meat, was associated with lower mortality, suggesting the importance of protein source."

Dr. Longo has also researched the benefits of fasting-mimicking diets. His research found that such diets improve factors that have a significant impact on health, particularly as people age, including body weight, blood pressure, and levels of glucose (sugar) in the blood.

Can the Longevity Diet Help With Weight Loss?

Any diet that includes mostly vegetables, fruits, and whole grains is likely to help you lose weight. This is true of the longevity diet as well as other plant-based diets.

What the Research Says

There has been very little research into whether this specific diet can help people live longer. Much of the research into this diet's health benefits has been done by the diet's founder and not by unaffiliated researchers.

There has also been very little research done into the effects of diet on human longevity in general. Such studies would need to span many decades, and so far there just aren't enough good long-term studies that can tell us how much of an impact a plant-based diet or intermittent fasting might have on human lifespan. 

Meat and Dairy

Certain elements of the longevity diet may not be necessary to promote a long and healthy life. For example, it is not known whether avoiding meat and dairy altogether can help lower your risk factors for age-related diseases. Many studies have found that it may be enough to simply choose lean meat and low-fat dairy products. 

Fasting-Mimicking

It is also unclear whether a fasting-mimicking diet can help increase longevity. One 2022 study did find that a diet similar to the longevity diet could help mice live longer, but animal studies don't always translate well to human populations.

A 2017 study found that fasting-mimicking reduces body weight and body fat and may help reduce risk factors for age-related diseases. However, it's important to note that this study was co-authored by Valter Longo, the diet's founder.

Intermittent Fasting

There has been more research into the effects of intermittent fasting on health and longevity, with some studies concluding that intermittent fasting can reduce risk factors for age-related diseases. However, it is important to note that not all intermittent fasting interventions are the same and the benefits can vary from program to program.

Most studies, including a review study published in 2021, note that more research is needed to determine what the negative effects of these eating plans might be. For example, intermittent fasting may be harmful for people who have a history of disordered eating. 

Summary

The longevity diet is an eating plan that combines a plant-based diet with intermittent fasting and occasional periods of fasting-mimicking. The goal of the diet is to help you live longer.

People following the longevity diet should eat plenty of fruits, vegetables, and whole grains. Meat and dairy should be avoided, though the diet does allow for small amounts of low-mercury seafood and occasional dairy products made from goat's milk. All food must be eaten within a certain time frame, and participants are advised to follow a five-day fasting-mimicking plan several times a year.

The research into whether or not this diet can help you live longer is limited. Always discuss any new diet with your healthcare provider before deciding if it's right for you.