What Is the Mediterranean Diet? A Clear, Evidence-Based Definition

The Mediterranean diet is a way of eating based on the traditional food patterns of countries bordering the Mediterranean Sea — especially Greece, southern Italy, and Spain — that emphasizes vegetables, fruits, whole grains, legumes, nuts, seeds, and olive oil, with moderate fish and poultry, limited red meat, and minimal processed foods. It is the most studied diet in nutrition research and has been ranked the #1 overall diet by U.S. News & World Report for seven consecutive years (2018–2024).

Where the Mediterranean Diet Comes From

The pattern was first described by American physiologist Ancel Keys after his Seven Countries Study (launched in 1958), which found that people in southern Europe had far lower rates of heart disease than those in the U.S. and northern Europe — a difference he attributed to their diet and lifestyle. The modern evidence base was built by two landmark trials:

• The Lyon Diet Heart Study (1999) — heart attack survivors who ate a Mediterranean-style diet had a 50–70% lower risk of a second cardiac event compared with a standard low-fat diet.
• PREDIMED (2013) — a large Spanish trial of roughly 7,400 adults that found a Mediterranean diet supplemented with extra-virgin olive oil or nuts reduced major cardiovascular events by about 30% versus a control diet.

The Core Principles

The Mediterranean diet is not a strict meal plan with rigid rules. It is a flexible eating pattern built on a few consistent principles:

1. Plant foods at the center — every meal is built around vegetables, fruit, whole grains, beans, lentils, and nuts.
2. Olive oil as the main fat — extra-virgin olive oil replaces butter and most other cooking fats.
3. Fish over meat — fish and seafood several times a week; poultry and dairy in moderation; red meat a few times a month.
4. Minimally processed foods — whole grains instead of refined; little added sugar; few packaged foods.
5. Shared meals and activity — the pattern includes eating with others and regular physical activity, not just the food on the plate.

What You Eat (and What You Limit)

Eat daily: vegetables, fruit, whole grains (oats, barley, whole-wheat, farro), legumes (beans, lentils, chickpeas), nuts and seeds, extra-virgin olive oil, herbs and spices.

Eat a few times a week: fish and seafood (especially oily fish like sardines, salmon, and mackerel), poultry, eggs, yogurt, and cheese.

Eat occasionally (a few times a month): red meat, sweets, and processed meats.

Limit or avoid: sugary drinks, refined grains (white bread, pastries), fried foods, and highly processed snacks.

For a full shopping list, see our Mediterranean Diet Food List: The Ultimate Shopping Guide.

Is the Mediterranean Diet the Same as a Low-Fat Diet?

No. The Mediterranean diet is moderate-to-high in fat — roughly 35–40% of calories from fat — but most of that fat is unsaturated, primarily from olive oil and nuts. Low-fat diets restrict total fat; the Mediterranean pattern restricts the type of fat (favoring unsaturated over saturated) rather than the total amount.

How Is It Different From Other Diets?

Unlike keto, paleo, or low-carb diets, the Mediterranean diet does not eliminate entire food groups. It includes bread, pasta, and rice — but in their whole-grain forms and in reasonable portions. It is also less restrictive and easier to sustain long-term, which is one reason it outperforms restrictive diets in adherence studies. (See our comparison: Mediterranean Diet vs Keto: Which Is Better for Weight Loss?.)

What the Evidence Says It's Good For

Decades of research link the Mediterranean diet to a lower risk of heart disease, type 2 diabetes, certain cancers, and cognitive decline, and to longer life expectancy. The details are in our companion piece: Mediterranean Diet Benefits: 9 Proven Benefits Backed by Research.

Frequently Asked Questions

Is the Mediterranean diet vegetarian?
No. It is plant-forward but not vegetarian — it includes fish, seafood, poultry, eggs, and dairy in moderation. It can easily be adapted to a vegetarian or vegan version.

Can you eat bread and pasta on the Mediterranean diet?
Yes — choose whole-grain versions and keep portions reasonable. Refined white bread and pastries are limited, not banned. (More in Can You Eat Pasta, Bread, or Rice?.)

Is the Mediterranean diet good for weight loss?
Yes. Studies show it produces weight loss comparable to or better than low-carb diets, with better long-term adherence. (See Is the Mediterranean Diet Good for Weight Loss?.)

Do you have to drink wine?
No. Wine in moderation (optional, with meals) is traditional, but it is not required, and health authorities do not recommend starting to drink for health.

Key Takeaways

• The Mediterranean diet is a flexible, plant-forward eating pattern from southern Europe, not a rigid meal plan.
• It is the most researched diet in nutrition, backed by the Seven Countries Study, the Lyon Diet Heart Study, and PREDIMED.
• Build meals around vegetables, whole grains, legumes, nuts, and olive oil; eat fish regularly; limit red and processed meat.
• It is linked to a lower risk of heart disease, diabetes, and cognitive decline, and to longer life.

Want a ready-made plan? Try our 7-day Mediterranean diet meal plan for beginners or read the full Mediterranean diet guide.