What does the Mediterranean diet consist of? Why is it important? Is it the diet or is it the climate? Are there any adverse side effects?

  • The Mediterranean diet ‘pyramid’
  • Why is the Mediterranean diet important?
  • Is it the diet or is it the climate?
  • Are there any adverse side effects?
  • Changes in the Mediterranean diet and lifestyle
  • Conclusions 

The Mediterranean diet ‘pyramid’

The Mediterranean diet is a diet traditionally adopted by populations bordering the Mediterranean Sea. The term diet is used in its original sense i.e., the kind of food a person or a community normally eats, rather than the restriction of food or calorie intake with the aim of losing weight.


The Mediterranean diet is largely plant-based and typically includes:

  • High consumption of:
    • fruit, vegetables, cereals (largely unrefined), legumes, pulses, nuts and seeds
    • olive oil, as the main source of dietary fat for cooking and dressing
  • Moderate consumption of 
  • fish (twice or more a week), cheese, poultry, eggs and red wine 
  • Low consumption of:
    • red and processed meats, sugar-sweetened beverages and other processed foods
    • butter, cream and animal fats.

Why is the Mediterranean diet important?

There is scientific evidence that shows the health benefits of adopting a Mediterranean diet, with links to disease prevention and a better quality of life. The link between the Mediterranean diet and protection against coronary heart disease (CHD) was first established in by Ancel Keys in the Seven Countries Study. This 50-year-long study, started in the 1950s, essentially defined a ‘Mediterranean diet’ and found that it was not only associated with lower incidence and mortality from CHD, but was also associated with the lower death rates and the greater survival rates

Since then, research has shown health benefits of the diet in:

The PREDIMED (Prevención con Dieta Mediterránea) trial, carried out in Spain and published in 2018, is the largest intervention study to date. This trial found a 30% lower risk of cardiovascular disease in participants who had followed either a Mediterranean diet enriched with extra-virgin olive oil or a Mediterranean diet enriched with nuts, compared with participants who followed a low-fat controlled diet.

You can find a fuller assessment of the evidence for the health benefits of a Mediterranean diet in a companion article on the Age Watch website.

Is it the diet or is it the climate?

The benefits of the Mediterranean diet are thought to be linked with the overall healthy traditional lifestyle of populations living around the Mediterranean. In these countries, there is a tendency to eat meals together and to participate in regular physical activity, as well as their higher exposure to sunshine and the benefit of a climate conducive to enjoying outdoor fresh air.

So how do we know it is the Mediterranean diet which is making the difference?

We know that regular, modest exposure to the sun provides the body with Vitamin D. Vitamin D is believed to have a range of health benefits, although quite how wide a range is still being debated. So, the sun by itself could be a health factor.

Vitamin D is important for normal growth, the development of bones and teeth and for boosting the normal immune system functions to improve resistance against certain diseases.

However, the value of the Mediterranean diet has been demonstrated by studies which show that people who follow the diet in countries many miles away from the Mediterranean. For instance, a study of 380,296 people in the USA, published in 2007, found that the Mediterranean diet was associated with reduced all-cause and cause-specific mortality, including deaths due to cardiovascular disease (CVD) and cancer.

A study of 23,902 people in East Anglia in the UK reported that the more people followed a Mediterranean diet, the lower the rate of CVD and death appeared to be.

Greater adherence to the Mediterranean diet is associated with a lower CVD incidence and a lower mortality in the UK.

Are there any adverse side effects?

Our review has found no adverse effects mentioned in the research, with one possible exception. It has been found that sufferers from Irritable Bowel Syndrome (IBS) often benefit from a low FODMAP* diet. (FODMAPs are a group of sugars that are not completely digested or absorbed in our intestines and can aggravate IBS symptoms.)

Unfortunately, some otherwise healthy fruit, vegetables and other food sources contain FODMAPs. This doesn’t mean that people with IBS should abandon a Mediterranean diet. However, they may need to be more selective about which fruits, vegetables and other foods they eat. The British Dietetic Association has some useful tips on how to manage IBS symptoms.

(*FODMAP = fermentable oligosaccharides, disaccharides, monosaccharides, and polyols)

Changes in the Mediterranean diet and lifestyle

As with many other countries, people in the Mediterranean are now consuming more western foods, including sugar-sweetened beverages and foods high in fat, salt and sugar. Given the evidence for the benefits of the Mediterranean diet, people in Mediterranean countries are likely to gain greater health benefits from maintaining their traditional, diverse diets that are rich in plants, wholegrains, nuts and fish. 

MD - F&F


  • The Mediterranean diet contains a balanced mix of healthy ingredients, based on the natural produce people have been eating for many years, rather than a short-term diet fad or fashion.
  • Most studies suggest a positive association between following a Mediterranean diet and significant health benefits, such as:Following the Mediterranean diet is likely to help us lead longer, healthier lives.
    • reducing the risk of cardiovascular disease
    • reducing some cancers
    • helping to manage type 2 diabetes
    • supporting weight management
    • slowing cognitive decline
    • reducing the risk of Alzheimer’s and Parkinson’s.
  • Aim to eat plenty of fruit, vegetables, cereals, pulses, nuts, seeds, herbs and olive oil. (Not to forget red wine in moderation!)
  • Consume moderate amounts of fish, cheese, poultry, eggs, with only small amounts of red meat and saturated fats. 

Reviewed and updated by Nicole Musuwo, December 2020. Next review date November 2024.


Other relevant articles on the Age Watch website: