Mediterranean Diet And Obesity- The Scientific Truth

Mediterranean diet has received a lot of attention from researchers and nutritionists due to low prevalence of diseases in people consuming it.

Mediterranean diet is considered as a nutritional model or rather a pattern of eating than a just a literal ‘diet’.

This is because Mediterranean diet refers to a number of different diets followed by people living in countries bordering the Mediterranean Sea. For example Italians consume a higher proportion of pasta, the Greek consume fish in larger proportions.

Even in the same country, diet patterns differ like in South Italy average consumption of fruits, cereals and grains whereas in North Italy milk and dairy products are higher.

The diet in Crete is similar to what scientists refer to as Mediterranean diet. Crete diet is rich in high quality foods like vegetables, fruits and low in meat and dairy products. Two other essential components are olive oil and red wine.

Among the different populations in Mediterranean region, the Cretans have the best health status and lower incidence of cancer, heart attacks and other metabolic diseases which is why their diet is now the focus of scientific research.

For convenience sake Mediterranean diet is referred to as MeDiet in this article.

What is a Mediterranean diet?

Roughly you could say a Mediterranean diet comprises of whole and fresh food and lacks processed food. Also Mediterranean diet is a lifestyle change rather than just a diet because it is a healthy way of eating and is incomplete without physical activity.

This is what you can expect in a typical Mediterranean diet:

  • Large amounts of fruits, vegetables, cereals, breads, nuts and seeds
  • Olive oil as the principle source of fat
  • Moderate amounts of dairy products, fish, poultry and very little use of red meat
  • Eggs no more than 4 times a week
  • Wine- 2 glasses a day for men, 1 for women

mediterranean diet image 1

Adapted from:  http://oldwayspt.org/resources/heritage-pyramids/mediterranean-pyramid/overview

Mediterranean Diet pyramid was used as a visual tool to represent the classic Mediterranean diet in a conference at Cambridge,MA by Oldways, the Harvard School of Public Health, and the European Office of the World Health Organization.

The base of the pyramid is marked by ‘physical activity’ making it a daily essential while red meat lies on the top of pyramid making it an occasional food item (350-450g per month).

This is what a Cretan version of Mediterranean diet would be:

  • 40% calories from fat mainly olive oil
  • Low level of carbohydrate (45% of daily calories) from fruits (2-3) and vegetables (2-3 cups a day)
  • 8 slices of whole grain bread and their bread has a low glycemic index in comparison to conventional bread
  • Moderate intake of fish rich in omega fatty acids (40g per day)
  • Higher intake of meat
  • Higher intake of alpha linoleic acid from nuts, seeds and greens

What does this mean?
Mediterranean diet consists mainly of greens, fruits, dairy, fish, olive oil and wine. It lacks processed food and incorporates very little red meat. Physical activity is also a core element of Mediterranean diet.

What does science have to say about role of Mediterranean diet in obesity?

Mediterranean diet has been studied mainly because of the favourable health status of people following this diet traditionally. It is not exactly focussed on the aim of inducing weight loss however those following this diet have lower incidence of obesity and other risk factors for obesity.

MeDiet has an anti-obesity effect

The Seven Countries study was perhaps the first study to tout the health benefits of the MeDiet.  The results showed reduced mortality from heart diseases in countries following this diet and also addressed the link of this observation with obesity.

Observational studies report that those following Mediterranean diet are less likely to be overweight or obese.   A review of 21 epidemiological studies was conducted where 13 studies showed that following Mediterranean diet was significantly related to lower incidence of obesity and more towards weight loss.

A 2 year study was conducted wherein 322 obese individuals were assigned to either low fat, low carb or Mediterranean diet.  Weight loss was highest (4.7kg) in low carb group followed by MeDiet (4.4kg) and (2.9kg) low fat group. The MeDiet group consumed maximum fibre and had a healthy ratio of monounsaturated fat and saturated fat and also improvement in diabetes related parameters.

Another comparative study between MeDiet and low fat diet reported an average weight loss of 4.1kg and decrease in waist circumference of 6.9cm in 18 months with MeDiet.

Meditterean diet featured image

A meta-analysis of studies investigating the link of MeDiet and improved cardiovascular function revealed that a 2 year adherence to MeDiet resulted in weight loss and BMI change as well as improvement in metabolic parameters.  Calorie restricted MeDiet is proven to cause a significant drop in weight (>5%) in 4 months.

In the famous clinical trial focussed on Mediterranean study, PREDIMED study , participants were assigned to the following studies:

  • MeDiet with extra virgin olive oil
  • MeDiet with nuts
  • Low fat diet

A 14 item questionnaire was used to assess the prevalence and obesity (general and abdominal) and adherence of MeDiet ; an inverse association was reported between the two.

Anti-obesity effect of MeDiet has been proven to be effective even in childhood obesity.  The SUN study by Harvard School of Public Health reports that MeDiet is effective in reducing age related weight gain.

The dietary reasons why this diet may exert an anti-obesity effect:

  • Presence of large amount of dietary fibre, low energy density and low glycemic index foods
  • Low meat content
  • Presence of monounsaturated fats which increases fat oxidation and diet induced increase in metabolism
  • Omega 3 fatty acids
  • Resveratrol and other antioxidants in wine

What does this mean?
Mediterranean diet brings about modest effect on body weight in long term and is effective in reducing obesity in all age groups.

It is associated with lower abdominal fat

Observational studies report that higher adherence to MeDiet is strongly associated with lower waist circumference.    Inclusion of foods rich in antioxidants as well as nuts in this diet are said to help in reducing abdominal obesity.

The KEMPHY diet (ketogenic Mediterranean diet with phytoextracts) is proven to reduce waist circumference (by 9 cm) and weight (by 7 kg) in 6 weeks.

Research suggests that MeDiet can have beneficial effects on abdominal obesity which can in turn reduce the risk of cardiovascular diseases.

What does this mean?
Greater adherence to MeDiet means lower the waist circumference.

It reverses metabolic syndrome

Metabolic syndrome is a group of health conditions such as high blood sugar levels, high blood pressure, abdominal obesity, high cholesterol level which increases ones risk to developing heart diseases or diabetes.

The PREDIMED study focuses on the effect of MeDiet on various health aspects. Results of the this study  demonstrated that MeDiet supplemented with nuts or extra virgin olive oil do not lead to onset of metabolic syndrome but reverse this condition. Additionally it was also found to reduce central obesity and blood sugar levels.

MeDiet even in the absence of weight loss brings about favourable changes in cholesterol and blood sugar levels and also reduces blood pressure, all of which aids in reducing risk factors of metabolic syndrome.

What does this mean?
Foods included in MeDiet help reverse metabolic syndrome and also prevent its onset irrespective of its effect on weight loss.

MeDiet is an excellent option for weight loss maintenance

Most studies regarding MeDiet have been conducted for a period of 1 year or more and they all show better adherence to the diet in comparison to alternatives and this also results in weight loss and preventing chances of weight gain.

The EPIC-PANACEA study reported that individuals who strongly adhered to MeDiet for 5 years were 10% less likely to be obese or overweight.  A review study  reports that adherence to MeDiet increases intake of dietary fibre, reduces consumption of saturated fats and incorporates physical activity.

All of these components together form a healthy lifestyle which aids in successful weight management.

One of the PREDIMED studies involving a follow up of 3 years reported that a MeDiet supplemented with extra virgin olive oil reduces the risk of weight gain.

What does this mean?
MeDiet not only helps you shed the kilos but also helps in putting it off in the long term.

Modified MeDiets for weight loss

For those who have no experience with Mediterranean diet, at times find it difficult to adapt despite of the wide variety of foods and a good deal of healthy fat incorporated into it. So a group of German researchers decided to modify this diet and test its efficacy in weight loss.

mediterranean diet image 2They replaced olive oil with neutral or butter flavoured canola oil, walnuts or walnut oil and also included two portion controlled sweets per day.

Weight loss after 12 weeks was 5.2kg and waist circumference decreased by 4.7 cm. Improvement in cholesterol levels was observed.

Average weight loss after 12 months was 4.2kg. Researchers concluded that fat modification does not deprive MeDiet of its weight loss effect.

Researchers have tested the efficacy of ‘biphasic ketogenic Mediterranean diet with phytoextracts’ on weight loss.  Ketogenic translates as very low carbohydrate while phytoextracts should be pharmacologically active plant based ingredients which aid in weight loss.

In this trial participants were given alternating phases of Mediterranean diet and low carb diet.

Average weight loss was around 10kg and fat loss was about 10% in 12 months. Successful weight maintenance and reduction in health risk factors was observed in majority of the participants.

A Mediterranean type of breakfast can control appetite for more than 4 hours and reduce energy intake at subsequent meal.

What does this mean?
Some people find it difficult to adapt to the generous use of olive oil in Mediterranean diet. Replacing it with canola or walnut oil is not going to affect the health outcomes of this diet.

Alternating MeDiet with a low carb diet is also a great technique for successful weight loss and weight maintenance.

It reduces the risk of developing a number of diseases

Results of the PREDIMED study indicate that a vegetable based diet that is rich in saturated fat and polyphenols is an excellent means of reducing heart and metabolic diseases.  The Lyon Diet Heart Study which recruited people from Lyon, France reported that Mediterranean diet reduced the mortality rate due to heart diseases.

Additional research has proven that MeDiet prevents the following conditions:

What does this mean?
The Mediterranean diet is a nutritionally recommended eating pattern and incorporation of foods rich in antioxidants, healthy fats as well as minimal use of processed foods makes this diet therapeutic in a number of health conditions.

What would it mean to follow a Mediterranean diet?

I would have to research a little bit more before giving you an appropriate answer to this. But till then here is a chart that gives you some basic guidelines on the Mediterranean diet.

Frequency Food Tips
Monthly Red meats No more than few times a month
Weekly Sweets Opt instead for natural fresh fruits
Eggs Less than 4 per week including those in processed foods
Poultry Few times a week. Remove the skin and choose white meat for low fat intake
Fish Few times a week
Daily Cheese and yogurt Good sources of calcium. Choose low fat varieties
Olive oil Good source of antioxidants and MUFAs. High in calories so consume in moderation
Fruits At least 1 serving at every meal
Vegetables At least 1 serving every meal
Beans, legumes and nuts Beans are a healthy source of protein and fibre that lowers cholesterol. Nuts are rich in MUFAs and can serve as snacks
Whole grains Substitute whole wheat for white bread, brown rice for white rice and use whole wheat flour for baking
Water At least 6 glasses daily
Wine 1 5 ounce glass daily for women and 2 (10 ounces) for men
Physical activity 30 minutes of exercise

Adapted from: The Gale Encyclopaedia of Diets, 2008 The Gale Group.

Precautions

Before making any drastic changes in your diet please consult your doctor. Those taking monoamine oxidase inhibitors to treat depression should be aware of their interaction with the compound named tyramine present in red wine.

It is advisable to keep a check on the portion size while using olive oil, cheese and yogurt or you could go for low fat version of dairy products. Make sure you buy organic virgin olive oil from reliable sources.

Conclusion

Among the different diets that I have read about till date, I am highly convinced that the Mediterranean diet is the utmost healthy pattern of eating. It would be great if you could follow this on a regular basis or perhaps with intermittent breaks of low carb diets.

The best part about this ‘diet’ is that it calls upon a lifestyle change and focuses on a whole diet approach where you don’t just modify one particular macronutrient. Also the Mediterranean diet is incomplete without physical activity.

So if you are looking for rejuvenation via a diet, Mediterranean diet assures you that.

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2 Comments

    1. If the plant based diet meets your daily nutrition requirements for proteins, fats and carbs..if its a balanced diet then there is no problem. Even Mediterranean diet focuses more on vegetables, fruits and cereals rather than animal protein.