Mediterranean diet, first long-term preclinical study


La Mediterranean diet protects against diabetes And fatty liver syndrome. And for the same number of calories – compared with the ‘Western diet‘, high in sugar and saturated fat-satisfies the appetite without making you fat. This is shown by the first preclinical study conducted over the long term.

A long-term study

The Wake Forest School of Medicine research is peculiar in the method adopted. Most studies on the benefits of the Mediterranean diet are indeed based on self-administration. Namely, on the food consumption reported by the subjects participating in the experiment and the monitoring of the functions it is intended to measure. By means of blood tests, ultrasound scans, and other diagnostic tests.

Macaques, which share about 99 percent of the genetic makeup with humans, are the protagonists of this study. (1) Thirty-eight middle-aged female primates (average age 9 years) participated in a trial that lasted a total of 38 months. Identical diet for the first 7 months in order to align the health status of participants in terms of body mass index and blood levels of triglycerides. In the following period (31 months, which is equivalent to 8-12 years of life for a human being), the primates were then put on a differentiated diet.

It is the first preclinical study, according to the researchers, in which the long-term effects of the Mediterranean diet on obesity and related diseases are measured under controlled experimental conditions. With only one limitation, represented by the smallness of the sample.

‘Med’ beats ‘

The two experimental diets were designed by the researchers with the aim of replicating human consumption patterns, offering each group the same energy intake (kcal/day) and identical amounts of macronutrients (protein, fat and carbohydrates).

The Western diet, ‘
, followed the ‘American style,’ in line with the average consumption indicated by the U.S. Department of Agriculture for women aged 40-49. A style essentially based on protein and animal fats, with saturated fat predominating over monounsaturated fatty acids and Omega-3.

The Mediterranean diet, ‘Med, was instead composed so as to ‘imitate key aspects of the Mediterranean diet‘. Predominantly plant-based proteins and fats, protein from fish and dairy products, good amounts of monounsaturated fatty acids and Omega-3, lots of complex carbohydrates and fiber, low amounts of sodium and simple sugars.

Mediterranean diet against fatty liver

At the end of the trial, primates fed the ‘West‘ diet accumulated more body fat, worsened triglyceride levels and liver condition, compared with those subjected to the ‘Med‘ diet. Such evidence, according to the researchers, attests to the effectiveness of the Mediterranean diet-which, it should be noted, should be supplemented with exercise-also in protecting againstNon-alcoholic Fatty LiverDisease ( NAFLD), also known as ‘fatty liver syndrome. A serious and widespread condition, which is often associated with obesity and can lead to serious diseases such as cirrhosis of the liver and liver cancer, needs transplantation.

The Western diet

, rich in sugars and saturated fats, promotes the occurrence of liver alterations, Among the major suspects, according to recent scientific publications, added sugars andpalmitic acid from palm oil

. As well as, in more general terms, ultra-processed foods and dietary fiber deficiencies.

The study‘Mediterranean versus Western Diet Effects on Caloric Intake, Obesity, Metabolism, and Hepatosteatosis in Nonhuman Primates,’ published on 4/23/19 in the journal ‘Obesity,’ is available free of charge in its full text. (2)

Marta Strinati


(1) Derek E. Wildman et al. (2003). ‘

Implications of natural selection in shaping 99.4% nonsynonymous DNA identity between humans and chimpanzees: enlarging genus Homo.

‘ Proc Natl Acad Sci U S A. 2003 Jun 10; 100(12):


. doi:

(2) Carol A. Shively et al. (2019). ‘Mediterranean versus Western Diet Effects on Caloric Intake, Obesity, Metabolism, and Hepatosteatosis in Nonhuman Primates’.,

Marta Strinati

Professional journalist since January 1995, he has worked for newspapers (Il Messaggero, Paese Sera, La Stampa) and periodicals (NumeroUno, Il Salvagente). She is the author of journalistic surveys on food, she has published the book "Reading labels to know what we eat".