Jump to: What is the Mediterranean diet? | Why has it become so revered by nutrition experts? | Weight management | Risk of chronic disease | Mental health | Are there any drawbacks? | The bigger picture
The Mediterranean diet has become the poster child of healthy eating over the past 50 years, with countries worldwide incorporating the Mediterranean diet into their public health guidelines.
Is the Mediterranean diet healthy? Absolutely.
There’s now enough research showing it can positively affect our health, reduce our risk of chronic diseases such as type-2 diabetes, and potentially improve our mental health.
However, that doesn’t mean we should all rush to change our eating habits to eat an exact match of the Mediterranean diet. We all come from different cultures with our traditions and food preferences.
The key insight from the Mediterranean diet is to generally eat more real food, more healthy fats, and lower your intake of highly-processed carbohydrates.
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Otherwise, keep reading for more information about the Mediterranean diet and its scientific evidence.
What is the Mediterranean diet?
Its origins lie in the countries from the Mediterranean region in southern Europe and the East, such as Italy, Spain, and Greece, where there was often a convergence of culture, trade, and agricultural processes.
Whilst there’s no official definition of the Mediterranean diet, as all regions will have unique cuisines and their intakes of different foods and ingredients will vary, a few critical elements of the diets remain consistent across the region: high intakes of extra virgin olive oil, fruits, vegetables, and whole grains, and moderate amounts of fish, dairy, and meat.
Traditional Mediterranean cultures also tended to have strong social bonds and communities. They’d eat meals with close friends or family while incorporating physical activity and movement into their daily routines.
- As the name suggests, the Mediterranean diet’s origins lie in the countries in the Mediterranean region.
- There’s no official definition of the Mediterranean diet.
- A few key elements are consistent across the region, such as high intakes of fruits and vegetables, extra virgin olive oil, and whole grains, with moderate amounts of fish, seafood, dairy and meat.
- Historically, the region has a culture of strong social bonds and communities.
Why has it become so revered by nutrition experts?
While its history is rooted in Mediterranean cultures dating back centuries, it first came to the attention of Western nutrition scientists in the 1950s through the work of Ancel Keys.
Keys was a scientist revered for his work in metabolism and developing rations for the U.S. army during the Second World War. Post-1945, heart disease in the U.S. started to increase and soon became the country’s number one cause of death.
Keys’ attention soon turned to the Mediterranean when an Italian colleague informed him that countries from the region had a very low incidence of heart disease.
Keys spent the preceding years analysing the diets and health of individuals across the Mediterranean regions and the U.S., Japan, and Finland, which became the now famous Seven Countries Study.
Keys’ findings supported his hypothesis as the Mediterranean countries showed lower rates of heart disease compared to countries such as Finland and the U.S.
In contrast, despite a very different diet to those in the Mediterranean, Japan showed similarly low rates of heart disease.
Key’s then developed the ‘diet-heart’ hypothesis, which suggested that a diet higher in unsaturated fats, such as those found in olive oil, nuts, and fish, and lower in saturated fats, such as those found in butter and cream, would lower your risk of heart disease.
The diet-heart hypothesis has since been a subject of intense debate between nutrition and health scientists.
This had a global impact on public health guidelines on nutrition. The U.S., the UK, Canada, Australia, and New Zealand adopted low-fat guidelines which advise people to eat diets rich in carbohydrates and low in fat.
- The Mediterranean diet was made famous in Western cultures through the work of Ancel Keys.
- While heart disease rates in the U.S. were high, rates in the Mediterranean were reportedly lower.
- Key’s seven countries’ study showed that Mediterranean countries had lower heart disease rates than the U.S. and Finland.
- Key’s then developed the diet-heart hypothesis, which influenced global public health guidelines on nutrition.
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A key measure of our health is maintaining a healthy weight. Being overweight or obese is associated with developing chronic diseases such as type-2 diabetes, heart disease, and some forms of cancer.
Multiple cross-sectional studies (a study that analyses data from a subset of the population) have shown that people who adhere to a Mediterranean diet are less likely to be obese.
One study showed that participants with high adherence to a Mediterranean diet were 51% less likely to be obese than those with low adherence.
Similarly, randomised controlled trials have consistently shown that a Mediterranean diet can aid weight loss.
One study compared a low-fat, low-carbohydrate, and Mediterranean diet and found that, after two years, people following a low-fat diet lost an average of 3.3kg, while those following a Mediterranean diet lost 4.6kg. Comparatively, those following a low-carbohydrate diet lost 5.5kg.
Recent research suggests that restricting fat may hinder your ability to lose weight as it may change the reward signalling in your brain, resulting in a desire to consume more energy-dense, ultra-processed foods, such as crisps, pastries, and sugary cereals.
Lower-carbohydrate and Mediterranean diets are naturally higher in fat from whole foods compared to low-fat diets and may support sustainable weight loss in the long term.
- Large cross-sectional, observational, and clinical trials have shown that the Mediterranean diet is an effectiove approach to support weight loss.
- Mediterranean diets are naturally higher in fat than the traditionally recommended low-fat diets, which may support sustainable weight loss.
Risk of chronic disease
A large randomised controlled trial involving over 7,000 participants investigated the effects of a Mediterranean diet supplemented with added extra virgin olive oil or nuts, compared to a low-fat diet, in individuals at risk of cardiovascular disease.
The study is a primary prevention trial, as they want to know whether the diets impact individuals before they experience a cardiovascular event, like a stroke or heart attack.
The study found that the individuals on the Mediterranean diet with added extra virgin olive oil had a 31% lower risk of experiencing a cardiovascular event than those on the low-fat diet. In contrast, the Mediterranean diet with added nuts had a 29% lower risk than those on the low-fat diet.
The Mediterranean diet with added extra virgin olive oil was also shown to lower the risk of death from all causes compared to the low-fat diet by 10%.
Another randomised controlled trial with over 1,000 participants with existing cardiovascular disease investigated the effect of the Mediterranean diet on the risk of experiencing future cardiovascular events.
This is known as a secondary prevention trial, as they’re looking into the impact of the diet on individuals who already have the disease.
The study showed that a Mediterranean diet reduced the risk of experiencing another cardiovascular event, such as heart attack or stroke, by 27% compared to a low-fat diet.
Interestingly, the researchers also analysed how well participants adhered to their diets. They found that those on the Mediterranean diet could meet their minimum target of eating at least 35% of their calories from fat and averaged around 40%.
In contrast, those on a low-fat diet struggled to adhere to their target of eating less than 30% of their calories from fat, averaging 32%. This suggests that strict low-fat diets may be difficult to maintain in the long term.
- The Mediterranean diet, particularly ones supplemented with high-quality extra virgin olive oil, seems to lower the risk of several chronic diseases compared to low-fat diets.
- The higher fat intake typically enjoyed in Mediterranean diets may make them a more sustainable option compared to low-fat diets.
The link between diet and mental health is a relatively new area. The emergence of our understanding of the gut and how it impacts our mental health has led to more research being conducted in this area.
Considering diet is likely the best way to improve our gut health, it’s logical to assume that a healthy diet may also improve our mental health. But is there any evidence for this?
The SMILES trial was one of the world’s first randomised controlled trials looking into the effect of diet on individuals living with clinical depression.
The study compared the Mediterranean diet to a social support programme and found that the individuals following the Mediterranean diet achieved significantly improved depressive scores and higher remission rates (32.3%) than those in the social support group (8%).
Another randomised controlled trial compared the impact of a Mediterranean diet supplemented with fish oil tablets and social support on individuals living with clinical depression.
The study supported the results of the SMILES trial and showed the Mediterranean diet was more effective at improving depression than attending a social support group. Participants adhering to the Mediterranean diet also reported higher quality of life scores.
It’s important to note that these trials aren’t suggesting that a healthy diet is the most effective way of treating depression and mental health.
It’s possible that the social support interventions within these studies aren’t very effective for people living with depression, which may exaggerate the impact of diet interventions.
Mental illness is a complex issue with multiple factors, such as sleep, stress, previous psychological traumas, and genetics.
But these studies suggest that improving our physical health through improved nutrition may have both direct (improved gut health) and indirect (stable energy levels) effects on our mental health.
- Two randomised controlled trials have shown that a Mediterranean diet is an effective way to improve depression compared to social support groups.
- Mental health illness is a complex issue, and diet alone can’t be relied upon to support the long-term treatment of mental health conditions for many people.
Are there any drawbacks?
The main criticism of the Mediterranean diet is that it’s not culturally appropriate for everyone. It’s difficult to advise individuals living in the Middle East to eat a Mediterranean diet, for example, as it might not reflect the foods typically enjoyed in their culture.
There’s also been confusion in the past about what precisely a Mediterranean diet is.
Public health guidelines have often promoted the use of a low-fat Mediterranean diet, despite traditional Mediterranean diets being rich in fat from whole foods, such as olive oil, dairy, meat, and fish, and randomised controlled trials showing Mediterranean diets higher in fat are more effective at improving health outcomes.
- It may not be culturally appropriate to recommend the Mediterranean diet to everyone.
- There’s often been confusion as to what a Mediterranean diet is, with many countries advocating for low-fat diets, despite higher-fat Mediterranean diets being shown to be more beneficial for health outcomes.
The bigger picture
A Mediterranean diet is a healthy way to eat. There’s enough research showing that it can positively affect our health and reduce our risk of chronic diseases such as type-2 diabetes and potentially improve our mental health.
But should we all eat a Mediterranean diet? No. We’re all from different cultures with our own traditions with food, and it’s inappropriate to suggest that everyone from every country and walk of life should eat a Mediterranean diet.
What we can do, however, is focus on the key elements of the traditional Mediterranean diet and lifestyle that seems to promote good health:
- A diet rich in whole foods such as fruits, vegetables, meat, fish, dairy, and legumes, and low in ultra-processed foods such as refined grains and sugars.
- Strong social connections and community.
- Physical activity and movement.
- Healthy sun exposure.
- Eat mindfully, and enjoy your meals with your loved ones.
It’s likely that, while the Mediterranean diet has been proven to be a healthy way to eat, the overarching benefits come from the lifestyle of the individuals living in these regions, as opposed to the diet alone.