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What is the Mediterranean Diet?

Mary Flynn Sun Jan 25 2026
What is the Mediterranean Diet?

The “Mediterranean diet” refers to the diet consumed by people who live in countries, or parts of countries, that border the Mediterranean Sea. For example, it is the diet of southern Italy, not northern Italy. The traditional Mediterranean diet is plant-based and includes generous daily servings of extra virgin olive oil as part of meals. I purposely use the word “traditional” as the definition of the Mediterranean has grown over time to include foods that were not part of the original diet such as canola oil, and frequent fish and poultry consumption. The traditional Mediterranean diet was composed of foods that could be grown locally in the climate so it was a diet of necessity and the foods consumed varied by the seasons. It was the diet of peasants, not the wealthy, and moderation of intake was common. The health benefits of the Mediterranean diet were initially realized in the 1950’s by studying people who ate this diet for generations.

Health officials in the US acknowledged the health benefits of a Mediterranean diet by the 1970’s. When it was first defined the total fat content of the diet was slightly higher than the typical American diet, but the fat in the Mediterranean diet was primarily from olive oil, while it was beef (and seed oils) in the US. Despite the strong evidence that this high fat diet was related to great health in the Greeks and southern Italians, health officials in the US unfortunately decided in the 1980’s to recommend a low-fat diet for all Americans. I remember reading editorials in the 1980’s that discussed the health benefits of extra virgin olive oil, but the editorials mistakenly concluded that Americans would not accept an oil that has a taste so it was thought that Americans would not embrace olive oil. In addition, health officials in the US also mistakenly concluded that the health benefits of olive oil were due to the high monounsaturated fat content. Hence the development of canola oil, made from the rapeseed plant with the name “canola” coming from the trademark name of the “Rapeseed Association of Canada”. Canola oil has minimal taste and it is reasonably high in monounsaturated fat (62%), but not as high as olive oil (77%).

The idea that the monounsaturated fat content is responsible for the health benefits lead to the development of the Med diet score.1 The Med diet score gives points to foods that have been shown to have health benefits like vegetables, fruits, legumes, olive oil, nuts, and cereals and subtracts points for foods that are unhealthy, like meat and meat products and full-fat dairy. The Med diet score uses the ratio of monounsaturated fat to saturated fat in the diet being examined. If the populations that are being studied is in one of the Mediterranean countries, the MFA: SFA would likely be assessing at least some extra virgin olive oil. However, when the Med diet score is used to assess health outside Mediterranean countries, the data should be examined with caution as you would need to know what foods are supplying the MFA. For example in the US, the major source of MFA until about 2004 was meat.2

Starting in 2005, “salad cooking oils” caught up with meat, supplying 23.9 % of the monounsaturated fat in the US diet to 21.4% from meat. While olive oil consumption has increased in the US, in 2005 soybean oil represented close to 80% of the salad oils consumed in the US. 3 Since that time the soybean oil contribution has decreased with increases mainly in canola and palm oil.3 However, in 2010 (the last year data is available from the USDA) meat still supplied 21.5% of the MFA content of the US diet to 32.3% from salad cooking oils. Thus, a study using the Med diet score to assess health in the US has a better chance of finding no health benefit, and possibly harm, due to a large proportion of the food source of MFA could be meat or canola oil.

The expansion of the definition of the Mediterranean diet has contributed to much confusion when discussing the health benefits, which is concerning to many scientists. I was part of an international group who decided that there was a need to establish an accurate definition of the diet and we published a paper from our work.4 There were fascinating Zoom meetings as we hashed out how to bring some sensibility to the definition so it would be correctly defined and could be used to study health. Early on, it was decided we should call it the “traditional Mediterranean Lifestyle” as the word “diet” is from the Greek “diaita,” or way of life. A very important part of the diet for populations who consumed a Mediterranean diet was how the meal was consumed. One did not eat by themselves, but shared communal meals. This way of eating was part of a culture that was built on seasonality, sustainability, and was environmentally respectful.

Extra virgin olive oil is a critical component of the Mediterranean diet and is critical to the health benefits. Studies that test olive oil consumption have shown it to be related to decreasing the risk of a range of chronic diseases and improving numerous risk factors for chronic diseases. Some of the risk factors extra virgin olive oil has been shown to improve are blood pressure 5 6 7 insulin sensitivity, 8 blood levels of glucose and insulin, 9 10 11 levels of HDL 12 13 14 15 16 17 and HDL function.18 19 No other food has the range and magnitude of the health benefits of extra virgin olive oil. If the health benefits of extra virgin olive oil were due to the monounsaturated fat content, all studies using any type of olive oil would have the same health benefits and they do not. In addition, canola oil would show health benefits, and it does not.20 The health benefits of extra virgin olive oil are clearly due to the phenols found in extra virgin olive oil as studies assessing the benefits for varying amounts of total phenols show better benefits with higher phenol content (approximately greater than 200 mg/kg) and no benefit with low (< 50 mg/kg) phenol content, a level that would not qualify as extra virgin.21

The traditional Mediterranean diet included extra virgin olive oil out of necessity – it was the only oil option in the area. The fact that it is delicious and has numerous health benefits is indeed a fortuitous bonus. It is possible to see some health benefits from the Med diet score due to the foods receiving a positive score -vegetables, fruits, nuts, legumes- that could contribute to health. However, if the MFA: SFA value is used to assess the contribution from dietary fat outside of the Mediterranean countries, the results should be interpreted with caution.

Summary:

  • A Mediterranean diet is the traditional diet of countries that surround the Mediterranean Sea.
  • The traditional Mediterranean diet is plant based with seasonal and local produce so by definition it contains a variety of plant products.
  • Extra virgin olive oil is critical to the health benefits.

Footnotes

  1. Trichopoulou A, et al. Diet and overall survival in elderly people. Bmj 1995;311(7018):1457-60 ↩

  2. Promotion UCfHPa. Nutrient Content of the U.S. Food Supply, 1909-2010. ↩

  3. Trends in U.S. Edible Oil Consumption and the High Oleic Soybean Oil Opportunity. United Soybean Board, 2017. ↩

  4. Siddossis L, Lawson R, Aprilakis E, et. al. Defining the Traditional Mediterranean Lifestyle: Joint International Consensus Statement. Lifestyle Medicine 2024;5(4):5:e115. ↩

  5. Ferrara LA, Raimondi AS, d’Episcopo L, Guida L, Dello Russo A, Marotta T. Olive oil and reduced need for antihypertensive medications. Arch Intern Med 2000;160(6):837-42. ↩

  6. Moreno-Luna R, Munoz-Hernandez R, Miranda ML, et al. Olive oil polyphenols decrease blood pressure and improve endothelial function in young women with mild hypertension. Am J Hypertens;25(12):1299-304. ↩

  7. Perona JS, Canizares J, Montero E, Sanchez-Dominguez JM, Catala A, Ruiz-Gutierrez V. Virgin olive oil reduces blood pressure in hypertensive elderly subjects. Clin Nutr 2004;23(5):1113-21. ↩

  8. Ryan M, McInerney D, Owens D, Collins P, Johnson A, Tomkin GH. Diabetes and the Mediterranean diet: a beneficial effect of oleic acid on insulin sensitivity, adipocyte glucose transport and endothelium-dependent vasoreactivity. Qjm 2000;93(2):85-91. ↩

  9. Farnetti S, Malandrino N, Luciani D, Gasbarrini G, Capristo E. Food fried in extra-virgin olive oil improves postprandial insulin response in obese, insulin-resistant women. J Med Food;14(3):316-21. ↩

  10. Loued S, Berrougui H, Componova P, Ikhlef S, Helal O, Khalil A. Extra-virgin olive oil consumption reduces the age-related decrease in HDL and paraoxonase 1 anti-inflammatory activities. Br J Nutr;110(7):1272-84. ↩

  11. Madigan C, Ryan M, Owens D, Collins P, Tomkin GH. Dietary unsaturated fatty acids in type 2 diabetes:higher levels of postprandial lipoprotein on a linoleic acid-rich sunflower oil diet compared with an oleicacid-rich olive oil diet. Diabetes Care 2000;23(10):1472-7. ↩

  12. Cicero AF, Nascetti S, Lopez-Sabater MC, et al. Changes in LDL fatty acid composition as a response to olive oil treatment are inversely related to lipid oxidative damage: The EUROLIVE study. J Am Coll Nutr 2008;27(2):314-20. ↩

  13. Covas MI, Nyyssonen K, Poulsen HE, et al. The effect of polyphenols in olive oil on heart disease riskfactors: a randomized trial. Ann Intern Med 2006;145(5):333-41. ↩

  14. Flynn MM, Reinert SE. Comparing an olive oil-enriched diet to a standard lower-fat diet for weight loss in breast cancer survivors: a pilotstudy. J Womens Health (Larchmt);19(6):1155-61. (In eng). DOI:10.1089/jwh.2009.1759. ↩

  15. Marrugat J, Covas MI, Fito M, et al. Effects of differing phenolic content in dietary olive oils on lipids and LDL oxidation—a randomized controlled trial. Eur J Nutr 2004;43(3):140-7. ↩

  16. Oliveras-Lopez MJ, Molina JJ, Mir MV, Rey EF, Martin F, de la Serrana HL. Extra virgin olive oil (EVOO) consumption and antioxidant status in healthy institutionalized elderly humans. Arch GerontolGeriatr;57(2):234-42.. ↩

  17. Weinbrenner T, Fito M, de la Torre R, et al. Olive oils high in phenolic compounds modulateoxidative/antioxidative status in men. J Nutr 2004;134(9):2314-21. ↩

  18. Hernaez A, Fernandez-Castillejo S, Farras M, et al. Olive oil polyphenols enhance high-density lipoprotein function in humans: a randomized controlled trial. Arterioscler Thromb Vasc Biol;34(9):2115-9. ↩

  19. Pedersen A, Baumstark MW, Marckmann P, Gylling H, Sandstrom B. An olive oil-rich diet results in higher concentrations of LDL cholesterol and a higher number of LDL subfraction particles than rapeseed oil and sunflower oil diets. J Lipid Res 2000;41(12):1901-11. ↩

  20. Hoffman R, Gerber M. Can rapeseed oil replace olive oil as part of a Mediterranean-style diet? Br J Nutr 2014;112(11):1882-95. DOI: 10.1017/S0007114514002888. ↩

  21. Castaner O, Covas MI, Khymenets O, et al. Protection of LDL from oxidation by olive oil polyphenols is associated with a down regulation of CD40-ligand expression and its downstream products in vivo in humans. Am J Clin Nutr;95(5):1238-44. ↩