Mediterranean diet: A complete guide
Search for tips on adopting the Mediterranean diet, and you’ll come across a slew of books, articles, and blogs published within the past two decades. But the diet’s origins date back to biblical times when scripture cited some of the Meditterranean Diet’s basic components—wheat, barley, grapes, figs, pomegranates, olives, and fish.
The American physiologist and researcher Ancel Keys shaped our modern understanding of the Mediterranean diet—especially its health claims. After studying the way Greeks, Italians, Spaniards, and other inhabitants of the Mediterranean basin ate—and finding fewer instances of cancer, heart disease, and all-cause mortality among them—Keys and his wife Margaret linked local eating habits to health and longevity in their 1960 bestseller, How to Eat Well and Stay Well the Mediterranean Way.
Subsequent research by Antonia and Dimitrios Trichopoulou and Walter Willett underscoring the Mediterranean diet’s benefits led physicians, dietitians, and laypeople to recommend and adopt the eating style. So what exactly does the diet entail? And does the hype hold up under a rigorous scientific lens? Below, a look at the research on what the Mediterranean diet can actually do for you.
What is the Mediterranean diet?
Roughly speaking, the Mediterranean diet seeks to recreate the average nutritional intake of someone living in the Mediterranean region. Namely: 1960s-era Greece (especially Crete, Greece’s largest island), Southern Italy, France, and Spain, whose inhabitants were found to have better heart health and longer life spans relative to their counterparts in the United States and Northern Europe, explains Dr. William Li, M.D., author of Eat to Beat Disease: The New Science of How Your Body Can Heal Itself. Although weight loss wasn’t the original aim of the Mediterranean diet (as coined by Keys), shedding pounds was seen as a byproduct of adopting a healthier eating pattern that lowered cardiovascular disease and all-cause mortality risk.
What did this allegedly healthier eating pattern entail? “Fresh produce, fish, healthy fats like olive oil and nuts; small amounts of dairy, eggs, and poultry, and limited red and processed meats,” explains dietitian and health coach Jessica Cording, MS, RD, CDN, Kettlebell Kitchen’s nutrition consultant and author of The Little Book Of Game-Changers: 50 Healthy Habits For Managing Stress & Anxiety. This typically breaks down to a distribution of macronutrients (i.e., fat, protein, and carbohydrates) that’s very different from traditional Western diets. Whereas Americans typically eat more saturated fats and simple carbohydrates thanks to our higher consumption of red meat and processed foods, the Mediterranean Diet relies more heavily on unsaturated fats and complex carbohydrates.
“Whole grains and legumes are recommended over refined grains, and concentrated sweets are kept to a minimum,” Cording explains of the Mediterranean diet. “Moderate amounts of wine may also be included in this diet pattern—up to one glass per day for women and up to two per day for men.”
As for the greasy pizza pies and mounds of pasta some of us associate with Mediterranean (especially Italian) cuisines? Alas, these aren’t included in the Mediterranean diet, says Dr. Li.
But the Mediterranean diet is more than just a series of nutritional calculations. Embedded within it is a philosophy on eating and health that stretches beyond food intake alone. Integral to the Mediterranean diet are five key concepts: Moderation, conviviality (cooking and eating as a communal activity), savouring the process of food preparation and cooking, designing meals according to foods’ seasonality, and engaging in regular physical activity (not necessarily planned or forced but integrated into daily life—think: walking, taking the stairs, engaging in leisure activities outdoors, or doing housework).
Foods to eat on the Mediterranean diet
To achieve the “ideal” balance of unsaturated fats, veggies, fruits, legumes, and whole grains, Mediterranean diet adherents incorporate the following foods into each meal:
- Vegetables: Amaranth (often misidentified as a grain), artichokes, arugula, beet greens, beets, broccoli, brussels sprouts, cabbage (red or green), carrots, cauliflower, celery root and celery, chicory, collard greens, cucumber, dandelion greens, eggplant, fennel, garlic, horta, hot chili peppers, kale, leeks, lettuce, mushrooms, mustard greens, nettles, okra, onions (white, red, and sweet), pear greens, peas, peppers (red, green orange, yellow), purslane, radicchio, radish, scallions, shallots, spinach, sprouts, squash and squash blossoms, sweet peppers, and zucchini
- Tubers: Potatoes (especially purple and sweet potatoes, Dr. Li says), rutabaga, sweet potatoes, turnips, and yams
- Fruits: Apples, apricots, bananas, bergamot (a citrus fruit), blackberries, cherries, clementines, dates, figs, grapefruit, grapes, lemons, melons, nectarines, oranges, peaches, pears, pomegranates, pumpkins, strawberries, tangerines, and tomatoes
- Nuts and seeds: Almonds, cashews, chia seeds, hazelnuts, macadamia nuts, pine nuts, pistachios, pumpkin seeds, sesame seeds (tahini, when blended), sunflower seeds, and walnuts
- Legumes: Beans (chickpeas, cannellini beans, fava beans, kidney beans, black beans), lentils, peas, peanuts, and pulses (i.e., lima beans, butter beans, etc.)
- Whole grains: All-bran cereal, barley and paximadi (barley rusks), buckwheat, bulgur, brown rice, corn, couscous, oats, polenta, rye, whole grain bread, and pasta
- Fish and seafood: Abalone (sea snails), anchovies, anchovy juice (colatura di alici), bottarga (grey mullet fish roe), calamari, cockles (a kind of saltwater clam), cod, clams, crab, eel, langostines, mackerel, mullet, mussels, octopus, oysters, salmon, sardines, sea bass, scallops, shrimp, spiny lobster, squid, tilapia, trout, tuna, whelk (a kind of sea snail), and yellowtail
- Meat and poultry: Chicken (breast or thighs with fat trimmed), duck, goat, guinea fowl, lamb, mutton, quail, turkey
- Eggs: Chicken, duck, and quail eggs
- Dairy: Brie, chevre, corvo, feta, graviera, Greek (a.k.a. strained) yogurt (aim for whole, unsweetened, Dr. Li recommends), halloumi, manchego, mozzarella (fresh), mitzithra (a fresh cheese similar to ricotta), ricotta, parmesan cheese, pecorino, and sheep’s milk yogurt
- Herbs and spices: Allspice, anise, basil, bay leaf, chamomile, chiles, cinnamon, clove, cumin, dill, fennel, garlic, lavender, marjoram, mint, nutmeg, oregano, parsley, pepper, pul biber (Aleppo pepper), rosemary, sage, sea salt, sumac, tarragon, thyme, and za’atar
- Healthy fats: Extra virgin olive oil (especially from Koroneiki, Moraiolo, and Picual, recommends Li), olives, avocados and avocado oil, fish oil, nut butters and oils, and tahini (a paste made from sesame seeds)
- Sauces, dressings, and other add-ons: Aioli, balsamic vinegar, honey, pesto, red wine vinegar, tomato sauce, and tzatziki
- Beverages: Coffee, red wine, tea, and water
- Desserts: Sweets are not recommended for daily consumption on the Mediterranean diet; however, moderate consumption of traditional treats, which tend to be made with fruit, nuts, whole grains, and little sugar, are permitted, including baklava, biscotti, crème caramel, chocolate, gelato, kunefe, mousse au chocolat, sorbet, and Turkish delight (a.k.a. lokum).
The bulk of protein in a typical Mediterranean diet, which places less emphasis on red meat and poultry compared to what most of us are used to in the U.S., comes from beans, lentils, chickpeas, and nuts as well as fish and other seafood, Cording explains. Dairy products, nuts, and seeds (as well as some whole grain products) also contribute to many Mediterranean dieters’ protein intakes.
Vegetables and fruits—the fresher, the better, as per the Mediterranean diet—are consumed in abundance, and none are off limits, Cording says. Exceptions are made for items like tomato paste, sun-dried tomatoes, and olives. If you’re on a budget—or prefer to buy all your groceries in one fell swoop rather than replace perishable produce daily—frozen fruits and vegetables have been found to be just as—if not more—nutritious as fresh ones.
Foods to avoid on the Mediterranean diet
On the Mediterranean diet, cheeses, processed and red meats, and sweets are enjoyed regularly, but in small portions. By prioritizing quality over quantity, the eating style encourages you to be selective about where your calories are coming from. These nutrients are found in food products that are limited on the Mediterranean diet including:
- Added sugars: Organic tapioca syrup, cane sugar, corn sweetener, corn syrup/high fructose corn syrup, crystalline fructose, dextrose, evaporated cane juice, caramel, coconut sugar, agave, honey, date paste, and maple syrup.
- Note: The number one source of added sugar in the American diet is sugar-sweetened beverages, like soda, sports drinks, coffee and tea beverages, smoothies and fruit-drinks, and alcohol mixers. Soda, sweetened trail mixes and sugar-coated nuts, candy, and ice cream also tend to be chock full of these additives, as are yogurts with excess added sugars, Cording cautions. Aim to cap flavoured yogurts at 11g total sugar, or stick to plain versions and sweeten with other ingredients you love.
- Refined grains: Pastries, cakes, muffins, toaster strudel, frozen griddle cakes (waffles, pancakes), some crackers and breads, sugary cereals (including many hot cereals), and dried fruit with added sugars (i.e., in store-bought trail mix)
- Dairy desserts: Ice cream, and sugar-sweetened milks/plant-based milks (like chocolate and strawberry), milkshakes, cream, and whipped cream toppings.
- Red and processed meats: Bacon, beef, ham, hot dogs, processed meat products (chicken nuggets, fried meats or poultry, mechanically-separated meat or poultry), and processed sausages
- Condiments: Sauces, dressings, marinades, and concentrated sugar spreads like jelly
- Beverages: Bottled sweetened coffees, fruit juices, sodas, and sugary alcoholic mixers
Potential health benefits of the Mediterranean diet
Beyond long-term weight-management, the Mediterranean diet has been linked to reducing the risk of diseases like cardiometabolic disease, some cancers, type II diabetes, Alzheimer’s disease, and neurodegenerative diseases such as Parkinson’s and multiple sclerosis, and all-cause mortality
The Mediterranean diet may also improve the quality of sperm as well as the odds of getting pregnant naturally or when undergoing in vitro fertilization (IVF). These benefits, research suggests, likely derive from the Mediterranean diet’s ability to help regulate blood sugar; lower bad cholesterol; promote the activity of stem cells, which help rebuild damaged cells and tissues; reduce inflammation and oxidative stress from free radicals; and promote healthy gut bacteria which produce metabolites that lower inflammation and support immunity, Dr. Li says.
“Vegetables, fruits, legumes, herbs, and spices”—which the Mediterranean diet is full of—“contain bioactive compounds that can help protect DNA from damage and possibly slow cellular aging,” Dr. Li says.
In fact, one study of 4,676 healthy middle-aged women showed that those whose diets closely resembled the Mediterranean eating pattern had longer telomeres—the protective caps on the end of chromosomes that keep DNA from unraveling as we age. And a 2011 study by researchers at the University of Cordoba in Spain found a five-fold increase in stem cells in the blood of 20 elderly men and women after they consumed a Mediterranean diet for four weeks.
What’s more, because the Mediterranean diet champions veggies, fruit, 100-percent whole-grains, pulses (like beans, chickpeas, peas, and lentils); lean protein like seafood, eggs, and lean meat, and gently encourages you to enjoy sweets and higher-in-saturated-fat choices as indulgences to be savoured in smaller amounts, it encourages more wholesome food choices and naturally limits the amount of sodium, saturated fat, and added sugar in daily meals and snacks.
Potential weight loss benefits of the Mediterranean diet
Studies show that adherents are less likely to overeat than people who eat Western-type diets. Researchers believe that the Mediterranean diet’s high volume of low-calorie, high-fiber, water-rich foods help people feel fuller for longer than the low-fiber, high-calorie, and high-sugar foods that comprise a typical Western diet.
The inclusion of healthy fats also contributes to feelings of satiety. Omega 3 fatty acid—an unsaturated fat found primarily in fish, walnuts, and soybeans—has been shown to improve cells’ ability to process blood sugar and lower harmful LDL cholesterol and triglyceride levels, Dr. Li points out. Some evidence also suggests that the unsaturated fats found in Mediterranean diets promote metabolism.
Potential health risks and disadvantages of the Mediterranean diet
While research suggests that the Mediterranean diet comes with a wealth of benefits, it does have a few drawbacks. For starters, if you prefer a more specific outline of what or how much to eat (and when), you won’t find that on this eating plan. This boundless flexibility could be misinterpreted as license to overdo it on “allowed” items because they are “healthy”—a psychological trap known as the “health halo effect”.
Eating large portion sizes—even of “good-for-you” items—can interfere with your weight, Li says. Overloading the body with calories also stresses the immune system and has been found to accelerate cellular aging—the opposite of what a Mediterranean diet based on moderate portion sizes aims to achieve.
What’s more, if you have food sensitivities to any of the diet’s staples, it may not be for you. The same goes for people with a history of substance misuse, or those who are pregnant, trying to become pregnant, or nursing, in which case the Mediterranean diet, which includes wine, isn’t advisable. Even beyond these demographics, the consumption of alcohol may not support your goals. While research has shown associations between drinking small-to-moderate amounts of red wine and improved cardiovascular health (as well as reduced risk for cancer, diabetes, and neurodegenerative diseases), more than the recommended one-to-two glasses a day isn’t encouraged. “It’s important to note that the benefits attributed to alcohol come from polyphenols found in fermented grape skins, not from the alcohol content itself,” Dr. Li says.
One very important consideration in weighing the Mediterranean diet’s benefits against its drawbacks is a recent retraction of one of the most scientifically valid studies of its heart health benefits: The PREDIMED (prevention of disease with the Mediterranean diet) study. After a skeptical researcher questioned the study’s methodology, the PREDIMED study was retracted from the New England Journal of Medicine, prompting many scientists to wonder whether the cardiovascular benefits attributed to the diet weren’t actually attributable to other factors—like lifestyle habits, lack of exposure to pollutants, socioeconomic status and education levels, or stress levels—all of which have been found to have an effect on our heart health independent of diet.
The upshot: Does the Mediterranean diet work?
The evidence in favour of the Mediterranean diet appears to be pretty favorable, though these benefits could be due to factors other than nutritional intake (as is the case with any diet’s purported health benefits). One component that’s often missed when examining the Mediterranean lifestyle is making lunch the largest meal of the day— a factor that may help to promote more physical activity in the afternoon hours, and help to limit sleep disturbances due to heavy meals before bed. But whether the Mediterranean diet "works" or not depends on a person’s goals and individual dietary needs or restrictions as well as their preferences for specific eating guidelines.
Because the Mediterranean diet doesn’t ban whole food groups like many other diets, adherents may find it less restrictive and, therefore, more sustainable over the long haul. But the same upside that makes some people consider the Mediterranean diet feasible can also be a drawback for those who need a more measured and specific approach to monitoring their food intake on a daily and weekly basis.
If your primary goal is weight loss and you prefer a semi-structured, but still flexible approach, combining a Mediterranean-style diet with a weight loss program like WW may lead to greater success.
Katherine Schreiber, MFA, MSW, co-author of The Truth About Exercise Addiction: Understanding the Dark Side of Thinspiration, is a social worker and freelance writer based in New York City. She specializes in working with adults with severe and persistent mental illnesses, like schizophrenia spectrum disorders. Her work has been featured by Psychology Today, Cosmopolitan, Shape, and TIME.
Reviewed by Jackie London, R.D., November 2019