What factor did researchers miss when praising the Mediterranean diet of Crete?
The Short Answer
Fasting. When researchers studied the famously healthy Cretans in the 1950s and 60s, they documented the olive oil, fish, vegetables, and wine, but largely overlooked that these Greek Orthodox Christians fasted for significant portions of the year. The traditional pattern included fasting periods totaling roughly 180 days annually, most of them partial fasts restricting animal products. The Mediterranean “diet” was also a calendar: stricter periods alternating with ordinary ones, and on Sarri’s evidence the stricter periods did measurable work through what was eaten.
Something to Sit With
If the Cretans’ remarkable health came from both what they ate and when they didn’t eat, what does that suggest for your own approach?
Are you focused entirely on food composition while ignoring eating patterns?
Learn More
The Seven Countries Study.
The famous Seven Countries Study, led by Ancel Keys beginning in 1958, documented remarkable cardiovascular health among people in Crete. Researchers cataloged their dietary patterns (high in olive oil, vegetables, legumes, fish, moderate wine) and attributed the health benefits to these foods.
This research launched decades of Mediterranean diet enthusiasm. Olive oil became a health food. Wine got positioned as cardioprotective. The Mediterranean diet became synonymous with healthy eating.
But the research focused on food composition while largely ignoring eating patterns.
What the Researchers Missed.
The Cretan population followed Greek Orthodox religious traditions, which include extensive fasting practices:
Great Lent: 48 days before Easter, with strict fasting (no meat, dairy, eggs, fish, oil, or wine on most days).
Assumption Fast: Two weeks in August before the Assumption of Mary.
Christmas Fast: 40 days before Christmas.
Apostles’ Fast: Variable length before the Feast of Saints Peter and Paul.
Weekly fasting: Wednesdays and Fridays throughout the year.
Add these together, and traditional Greek Orthodox practitioners were fasting or eating restrictively for approximately 180-200 days per year, roughly half the time.[1]
The Confounded Variable.
When you observe a population and note their good health alongside their diet, you attribute the health to the diet. But if that population also fasts regularly, how do you know which factor matters more?
Sarri and colleagues measured it. At the end of fasting periods: total cholesterol 12.5% lower, LDL 15.9% lower, BMI 1.5% lower.[2]
And then the finding that complicates the story this page was telling. The same study records why: during the fasts, dietary fat fell from 38% to 32% of energy and fiber rose 43%, and that dietary shift is what explains the lipid improvements, which partially rebound between fasting periods when the normal diet resumes.[2]
So the fasting periods were not a pure timing intervention with the food held constant. They were periods of eating differently, and the measured benefit tracks the difference in what was eaten.
The Modern Mediterranean Diet.
When the Mediterranean diet was exported to the rest of the world, the fasting component was stripped out. What remained was:
- Lots of olive oil
- Wine with meals
- Fish and vegetables
- Legumes and whole grains
People adopted the foods without the eating pattern. Many added olive oil to their existing meals without removing meals, and wine without subtracting other calories, and ate Mediterranean foods on an ordinary schedule every day of the year.
The modern “Mediterranean diet” is a food list, not a lifestyle pattern. It captures what the Cretans ate while ignoring when they ate and when they didn’t.
The Implication.
This doesn’t mean the Mediterranean food choices are bad: olive oil, vegetables, and fish are excellent foods. But the export took a steady-state food list from a population whose eating was cyclical, and on Sarri’s evidence the cycle was doing measurable work.
The honest version of this page’s claim, then. It is not that timing beats composition. It is that the traditional pattern alternated between two ways of eating, and the benefit that was measured attached to the stricter half, and faded when it ended. A food list averaged across both halves is not either of them.
What is not supported is the wider version: that the healthiest populations throughout history generally combined whole foods, limited eating windows, integrated activity, and strong community. That may well be true. It is not established.
Further reading:
- Sarri KO et al., “Effects of Greek Orthodox Christian Church fasting on serum lipids and obesity”[3] — BMC Public Health, 2003
- Trepanowski JF & Bloomer RJ, “The impact of religious fasting on human health”[4] — Nutrition Journal, 2010
- Keys A et al., “The diet and 15-year death rate in the Seven Countries Study”[5] — American Journal of Epidemiology, 1986
- Nestle M, “Mediterranean diets: historical and research overview”[6] — American Journal of Clinical Nutrition, 1995
Written by AI, directed and approved by me. How this is made →