The so-called green Mediterranean diet was tested in a large-scale clinical intervention study with 294 participants. Analysis showed that the green Mediterranean diet reduced visceral fat by 14 per cent compared to classic diets. The results of the 18-month study have been published in the journal BMC Medicine.
What makes the green Mediterranean diet special is its focus on plant-based foods which are high in naturally occurring chemical compounds called polyphenols. In recent years, their healthy and anti-inflammatory properties have been widely studied. Natural polyphenols are found in plant-based foodstuffs, such as green tea and walnuts.
The study saw participants eat according to the traditional Mediterranean principle. Meals contained a high proportion of vegetable protein and polyphenols, and less red meat. Every day, the subjects also consumed walnuts (28 grams), three to four cups of green tea, and a shake containing 100 grams of a particular strain of duckweed. Duckweed is a green aquatic plant rich in protein, iron, vitamin B12, other vitamins, minerals and polyphenols, and substitutes meat intake in the diet.
Reducing visceral fat is the real goal of weight loss, as it is more important as an indicator than a person’s weight or waist circumference. Visceral fat accumulates around internal organs over time, producing hormones and toxins that are linked to heart disease, diabetes, dementia and premature death.
Understanding the mechanisms of nutrients
The research was led by Iris Shai, a professor at Ben-Gurion University of the Negev in Israel, adjunct professor at the Harvard School of Public Health, and visiting professor at Leipzig University’s Faculty of Medicine. “The goal is to understand the mechanisms of different nutrients. For example, of positive ones like polyphenols, and negative ones like empty carbohydrates and processed red meat, on the pace of fat cell differentiation and their accumulation in the viscera,” says Professor Shai.
The research team, consisting of Israeli, American, Italian and Leipzig scientists, was the first to introduce the concept of a green Mediterranean diet. The researchers have shown in previous studies that the green Mediterranean diet has a variety of beneficial effects, ranging from the microbiome to age-related degenerative diseases.
Original title of the publication: The effect of high-polyphenol Mediterranean diet on visceral adiposity: the DIRECT PLUS randomized controlled trial. Doi: 10.1186/s12916-022-02525-8
The expert Professor Iris Shai assumed her role as Visiting Professor of Nutritional Sciences at the Faculty of Medicine an 1 April 2022.