Fasting Traditions and Longevity in Ikaria and Okinawa

The world's healthiest populations share one quiet habit: fasting. On a remote peninsula in Greece, Orthodox monks have restricted their eating habits for at least 1000 years by fasting for more than half of every year, and the health benefits are astounding.

The Ritual of the Fast

Fasting has been a spiritual practice — a ritual of self-denial — for thousands of years, and cultures have carried it on to this day. Orthodox monks in Greece follow a rigorous fasting calendar with only 180 days available for eating. Their diets are heart healthy — cholesterol levels have been measured at 183, 50% less than the Western average, as have triglyceride levels, at 72. Even more impressive, most monks surpass 90 years of age; this is not a fluke, but an established pattern. Ikaria, a Greek island neighboring the peninsula, shares the same fasting calendar and also reports high longevity, with one in three citizens living past 90 years of age and a reported dementia rate near zero, according to researchers. In Okinawa, Japan, the practice of hara hachi bu, eating to 80% full, has been passed down for generations. Okinawa is considered one of the world's top five regions for longevity. Theravada Buddhist monks across Southeast Asia have also adopted fasting, with a 14 to 18 hour fast every day since 500 BCE. The Hadza of Tanzania are another group known for fasting, with a natural 15-hour fast every day due to their hunter-gatherer lifestyle, resulting in a near-absence of metabolic disease. Muslims around the world practice 20-hour fasts during Ramadan, which has been shown to activate the body's cellular repair mechanism.

The Blue Zones

For years, longevity researchers have tracked down the keys to a long life. That search led them to the so-called Blue Zones, where people live the longest. The habits that help them live so long, consistently across these locations, highlight the role of community, the importance of food and exercise, and — crucially — the role of fasting. Whether the fasting is motivated by religion (as in Orthodoxy or Islam), community (as among the Hadza and the Okinawans), or life purpose (such as in Okinawa where the practice has been passed down through generations), the benefits are the same: a healthier, longer life.

The Evidence

The first clue that fasting promotes health is the common inclusion in traditions around the world. Analogous to the biomedical need to conduct rigorous testing, cultural practices endure only when they serve practical purposes — such as helping people live longer. Multiple scientific studies suggest, at the very least, that fasting is strong medicine. A 2024 study of Ramadan participants showed that during the month of fasting, the body undergoes cellular repair, which is itself a treatment for multiple illnesses. Studies on Okinawa, Japan demonstrate benefits of eating less: researching the population’s practice of hara hachi bu, the Okinawans have one of the lowest rates of diabetes and heart disease in the world. When applied to their lifestyle, the diet restrictions and the longer fast lead to better cardiovascular health.

The Natural Effects of Caloric Restriction

The Hadza of Tanzania have no concept of breakfast and naturally fast for 15 hours every day. This has led to a near-complete absence of metabolic disease. In addition, the Hadza have a diet that is about 70% plant based, which includes a lot of fatty red meat. One might say that food restrictions in traditional diets may contradict modern day wisdom, which largely advises a diet high in vegetables and fruit and low in meat, but the Hadza provide an exception. Their lifestyle and diet prove that having a caloric restriction, or fast, is more important than what is eaten in order to promote health.

Fasting: The New Science

A large body of research supports the findings that fasting promotes health. A meta-analysis of 108 studies suggests that fasting improves morbidities, including obesity, type 2 diabetes, cardiovascular disease and stroke, according to the 2024 report "Effects of Ramadan Fasting on Metabolic Health." This is not a phenomenon limited to a study of one country: the research includes participants from Asia, Africa, and Europe. Ramsay Zaoud, a nutritionist from the University of Manitoba, confirms that studies show that fasting can help prevent and even reverse diseases.

Adopting the Fast

Practical guidance for someone wishing to adopt the fast from these traditions would depend upon their lifestyle and spiritual beliefs. However, anyone who wants to adopt the fast could incorporate the following practices.

• Start Small: Aim to introduce small changes to your diet, such as intermittent fasting with a 12-hour eating window and a 12-hour fast, which is significantly less than a monk’s schedule. Then, increase the fast duration gradually, for example by an hour every week, until you can comfortably fulfill an 18 hour fast. Make sure to consult a doctor to ensure this is safe, especially for those with any medical conditions.
• Stay Active: It goes without saying that fasting is not an easy practice. Make sure to increase your water intake to make sure you can keep fasting safely, and unless you are fasting during the recommended times, do not skip meals or think you can make up the food through snacks. Monitor your energy levels, swelling, and physical reactions. Make sure to consult with a doctor if you experience any physical or mental discomfort.
• Monitor Caloric Intake: For those who are not comfortable fasting or who feel they cannot stick to a fasting schedule, start by limiting your calories and have a smaller portion of food. For example, eat until you are 80% full, as the Okinawans do by practicing hara hachi bu. This is as effective as fasting in promoting better health, according to various studies. This will help you stay on track and keep your physical condition healthy.