By Dr. Asnat Raziel, bariatric surgeon specializing in obesity treatment, metabolic health and healthy longevity; Director of the Multidisciplinary Center for Obesity Treatment, Assia Medical, Assuta Ramat HaChayal, Tel Aviv
The Mediterranean diet: why it is the most studied eating pattern in the world
The Mediterranean diet is one of the most thoroughly researched eating patterns in medicine. It is built on vegetables, fruit, legumes, whole grains, nuts and olive oil. Large trials have found that it reduces cardiac events, and long-term follow-up studies have linked it to a longer life. On top of that, it is delicious, flexible and already familiar to anyone who knows Israeli home cooking.
In this article I explain what the Mediterranean diet includes, what the key studies have shown, and how to actually get started.
What the Mediterranean diet includes
There is no single fixed menu. This is the traditional way of eating in the countries around the Mediterranean basin, such as Greece, Italy and southern Spain. An overview of the diet’s origins and definitions shows that the core principles are similar across all of them:
- Vegetables and fruit at every meal, in season and in a wide range of colors.
- Extra-virgin olive oil as the main cooking fat.
- Legumes, whole grains, nuts and seeds.
- Fish two or three times a week, and poultry in moderate amounts.
- Little red meat, little processed food and little sugar.
It is also a way of life: shared meals, eating slowly and staying physically active every day.
The Mediterranean diet and heart health
The strongest evidence comes from the PREDIMED trial in Spain. It enrolled 7,447 people aged 55 to 80 at high cardiovascular risk. The researchers assigned participants to one of three groups: a Mediterranean diet supplemented with olive oil, the same diet supplemented with nuts, or a low-fat diet. After about 4.8 years, the trial results showed a roughly 30% reduction in the relative risk of a major cardiovascular event in both Mediterranean groups.
In absolute terms, a cardiovascular event occurred in 3.8% of the olive oil group and 3.4% of the nut group, compared with 4.4% of the control group. It is worth noting that the original 2013 publication was retracted because of problems with randomization; the figures given here are from the corrected results.
The CORDIOPREV trial, meanwhile, studied 1,002 patients with existing heart disease. According to the CORDIOPREV results, over 7 years this way of eating prevented recurrent events better than a low-fat diet. The benefit was seen mainly in men. I have also written about the link between everyday habits and the heart in an article on a healthy lifestyle.
The Mediterranean diet and longevity
A large US follow-up study tracked 25,315 women for almost 25 years. The study’s findings show that the women who adhered most closely to this eating pattern had a 23% lower risk of death from any cause. That said, this is an observational study, so it shows an association, not necessarily cause and effect.
The researchers also found a partial explanation for the link: less inflammation, better insulin sensitivity, lower body weight and healthier blood lipid levels. These mechanisms are a major focus of longevity medicine. In other articles I have reviewed research on diet and the biological clock of aging, and offered a practical menu for longevity.
Weight, blood sugar and metabolic health
This is not an extreme weight-loss diet, but it can help you lose weight. The Israeli DIRECT trial, carried out in Dimona and led by Ben-Gurion University, compared three diets over two years. In the DIRECT study, average weight loss was 4.4 kg in the Mediterranean group, 4.7 kg on the low-carbohydrate diet and 2.9 kg on the low-fat diet.
Among participants with diabetes, the Mediterranean diet also improved fasting blood sugar and insulin levels more than the low-fat diet did. My message to patients is simple: the best diet is the one you can stick with. For some people, diet alone is not enough, and then it is worth considering medication alongside nutrition.
Fiber, the gut and inflammation
This way of eating is rich in dietary fiber from legumes, vegetables and whole grains. Fiber feeds the bacteria in your gut and so supports a diverse microbiome. Readers interested in the subject can learn more about microbiome testing and what it can reveal.
Cutting back on red meat and sugary drinks is also relevant for people with high uric acid and gout. Finally, real food is usually better than pills. I have written separately about when a supplement such as a multivitamin does have a place.
How to start a Mediterranean diet at home
You don’t need a dramatic overhaul. Try changing one thing each week, starting with the easiest. A practical guide from Harvard suggests a few simple steps:
- Swap butter and margarine for extra-virgin olive oil.
- Snack on a handful of nuts instead of processed snacks.
- Eat legumes at least three times a week.
- Serve fruit for dessert, and save cakes for special occasions.
- Drink water instead of sweetened drinks and juices.
The biggest obstacle is a busy life. In a week full of work and errands, it is easy to skip cooking. So it helps to prepare a pot of legumes or a tray of roasted vegetables in advance to last a few days.
The bottom line
The Mediterranean diet is based on real, mostly plant-based food, with olive oil and nuts. Large trials have shown fewer cardiac events, and follow-up studies have linked it to a longer life. It is also flexible, tasty and a natural fit for the Israeli kitchen. If you have a chronic illness or obesity, it is a good idea to build a personalized eating plan with a physician or dietitian. You can find out more about me on the Dr. Asnat Raziel page.
The information in this article is general and does not replace personal medical advice.
Frequently asked questions
Is the Mediterranean diet good for weight loss?
Yes. In the DIRECT trial, participants in the Mediterranean group lost an average of 4.4 kg over two years. Portion sizes still matter, though, because olive oil and nuts are high in calories.
How much olive oil should I have a day?
There is no single number that suits everyone. The principle is to use olive oil instead of other fats, not on top of them. If you are trying to lose weight, keep an eye on the amount.
Can I eat meat on a Mediterranean diet?
Yes, in moderation. The recommendation is fish and poultry in moderate amounts, and red meat only occasionally. Much of the protein also comes from legumes, dairy products and eggs.
Is the Mediterranean diet suitable for people with diabetes?
In most cases, yes. It is rich in fiber and low in refined sugar. Even so, anyone taking diabetes medication should consult their doctor before making a major change to their diet.
Sources
Mediterranean Diet Adherence and Risk of All-Cause Mortality in Women
Weight loss with a low-carbohydrate, Mediterranean, or low-fat diet
