hummusThe Mediterranean Diet offers a healthy, tasty, aromatic array of fruits, vegetables, whole grains, nuts, wild greens, fish, olive oil, and red wine while sharply reducing intake of milk products, meat, processed foods, and sweets. The MD prevents cardiovascular disorders, reduces the incidence of cancer and diabetes, and—it appears—curbs neurodegenerative processes. It is strange, therefore, that, in spite of the pressing need to confront the global obesity epidemic, the MD has received relatively little attention in regard to its potential for weight loss.

The MD is often ignored in discussions of approaches to weight loss, in part because there’s no profit in it for the diet and pharmaceutical industries. Besides, the MD is not really a diet at all in the sense of a way of reducing energy intake in order to reduce weight. It is rather a traditional cuisine—a mode of ordinary healthy eating. And it contains no agreed-upon prescriptions regarding portion size or the exact balance of various ingredients.

Nonetheless, the MD can perform splendidly at the very task that is the downfall of other diets: it possesses proven effectiveness as a way of maintaining weight. In almost every clinical trial of medical and commercial diets, the loss of some 2-14 kg over the first 6-12 months gradually gives way to regaining weight, so that after five years the dieter is often no better off than at the outset. In contrast, the palatability of the MD, its satiety-inducing ingredients, its natural appeal, its extensive network of suppliers and recipes, and its freedom from the calorie counting, weight worrying, extra expenses, and counseling typical of other diets make it much easier to pursue over the long term.

In addition, the MD has a low environmental footprint.  A Spanish study found that the MD in Spain could reduce greenhouse gas emissions by 72%, land use by 58%, energy consumption by 52%, and water consumption by 33%.  In contrast, adherence to an American dietary pattern would lead to major increases in all these key dimensions (Sáez-Almendros et al.  Envir Health 2013).

Scientific Evidence

We have solid evidence for the effectiveness of the MD in weight maintenance. For instance, high adherence to a MD was associated with lower risk of obesity over 3.3 years in a study of 17,238 women and 10,589 men from the Spanish cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC) (Giugliano D and Esposito K Curr Opin Lipidol 2008). In a recent three-pronged Israeli study (Shai I et al. NEJM 2008), a loosely defined Mediterranean Diet maintained weight loss of about 4.4 kg from Months 5 through 24 of a trial, whereas a low-fat diet group regained about 25% of weight lost in the first 5 months. The Atkins Diet (low carbohydrates) group actually outperformed the MD group, losing 4.7 kg. But it had initially lost more, then regained the lost weight. A 2001 study (McManus K et al., Int J Obes Relat Metab Disord) and other clinical trials found the same pattern of weight maintenance with the MD.

Most people naturally prefer the MD because it provides normal nutrition instead of reducing caloric intake (though that is also an option). In contrast, low-fat diets tend to fare relatively poorly in terms of palatability and the induction of satiety, so dieters often deviate from their prescriptions or abandon them entirely over time. Clearly, olive oil’s lipids and its gastronomic qualities enhance the taste of other components of the MD. In addition, there is intriguing evidence that moderate red wine consumption prevents body weight gain, at least in rats (Vadillo Bargallo et al. J Nutr Biochem 2006). Of course, olive oil and red wine in the MD also convey other health benefits not available in diets that radically reduce fat and eliminate alcohol. One conclusion could be that dieters who lose weight from any other diet should, as their weight loss slows down, switch over to the MD to maintain the weight reduction.  In other words, all dieters should eventually adhere to the MD!

What about the 14% saturated fat in olive oil?  One researcher, Caldwell Esselstyn, M.D. (www.dresselstyn.com) argues that this fat ultimately leads to somewhat poorer outcomes for heart patients versus those who follow his strict non-fat diet.  But he is the only researcher who says this.  The overwhelming majority of researchers think that the MD protects against heart disease and prevents sudden cardiac death and chronic heart failure even in patients at high risk of cardiac death (Michel de Lorgeril and Patricia Salen.  Publ Heath Nutr 2011).  Of all foods, olive oil appears to have the most reliable effect on lowering unhealthy low-density lipoprotein and boosting healthy high-density lipoprotein.  Still, some people with significant heart disease might wish to substitute canola, which has just half the saturated fat of olive oil.  But olive oil has excellent properties, including its high level of healthy polyphenols and its outstanding gustatory qualities, which turn eating vegetables (the healthiest food of all) from a chore into a highly desirable activity.  Consuming olive oil makes sense for anyone without a heart condition.  There is no evidence that a moderate amount of olive oil intake can do harm to a healthy person, and excellent reasons to believe that its monosaturated fatty acids and polyphenols protect against cardiovascular disease.

Some people argue for austere vegan diets that cut out milk products and eggs entirely.  Veganism is fine for the committed; but most people are not.  They fare much better with a tasty, satisfying, easily procured, and lovingly cooked Mediterranean Diet that they are delighted to eat and will stick with forever.   That diet can include fish and occasionally non-fatty meat, or it can be an ovo-lacto-vegetarian MD, which many people find captures double value:  the MD plus vegetarianism (with Vitamin B-12 supplements).

Evidence regarding weight loss with the MD is more fragmentary. It is hard to define a single standard MD; every study uses a different version. Also, the MD blends into the even less well-defined category of a moderate-fat diet. An Iranian study (Azadbakht L et al. Br J Nutr 2007), for instance, found that over 7 months a moderate-fat diet (like the MD) and a low-fat one performed equally well, but by 14 months the low-fat group had regained all but 1.1 kg whereas the moderate fat group kept its loss at 5.0 kg. But the study did not use olive oil, red wine, or other components of the MD. An Italian pilot study (De Lorenzo A et al. Diab Nutr Metab 2001) of a low-calorie, rather well-defined MD in 19 obese women found that they lost 6.6 kg on average over two months. So a low-calorie MD seems to work quite well for losing weight in the short run, and then it can be adjusted to normal MD intake for the long run. Of course, this conclusion requires large, high-quality trials to establish firmly.

A pilot study of a high-protein variant of the MD termed the Spanish Ketogenic Mediterranean Diet, relying heavily on fish and olive oil, reportedly led to an average 14 kg weight loss in obese subjects over 12 weeks (Perez-Guisado J et al. Nutr J 2008). Experimental approaches of this kind require further investigation and may lead to superior outcomes.

The Way Forward

None of the above studies focused on the contribution of daily activities and exercise to weight loss. But they clearly play a significant role. The rural Cretans of the 1950s who served as the original models of the MD lived lives of considerable physical activity, including a lot of walking.  After gaining weight when hobbled by a leg injury, this writer lost 10 pounds (4.5 kg) in 10 weeks down to his optimal weight simply by adhering to a filling, satisfying ovo-lacto-vegetarian MD and getting a great deal of low- and moderate-intensity exercise.

This suggests an even better solution for losing weight than a low-calorie MD, which might encounter problems of adherence (though there was not a single dropout in the Italian pilot study). Instead of trying to “diet” with the MD, one could just eat three square, fully satisfying meals (or four smaller ones) per day of the MD and undertake a moderate exercise program that would slowly reduce weight until finally one would reach one’s ideal weight. So it would become a question of getting into shape rather than of dieting. This approach would not appeal to those who seek quick results, but it would presumably make sense to many medical doctors and to millions of overweight and obese people who have sadly failed with other diets.


See also:   The Med Plus Diet (video) and Eat a Mediterranean Diet but Still Supplement?

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Kenneth J. Dillon is an historian who writes on science, medicine, and history.  See the biosketch at About Us.  Dillon eats an ovo-lacto-vegetarian Mediterranean Diet.

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