Green Mediterranean Diet Study

Visceral adipose tissue is a type of fat around internal organs that is much more dangerous than the extra "tire" around the waist. Therefore, reducing visceral fat is considered the true goal of weight loss as it is a more important indicator than a person's weight or the circumference of their waist.

Researchers have found in a new study that the green Mediterranean diet (MED) significantly reduces visceral adipose tissue. The Green-Mediterranean diet (MED) is twice fortified in dietary polyphenols and lower in red/processed meat.

The green Mediterranean diet was pitted against the Mediterranean diet and a healthy diet in a large-scale clinical interventional trial - the DIRECT PLUS. Subsequent analysis found that the green Med diet reduced visceral fat by 14%, the Med diet by 7%, and the healthy diet by 4.5%.

The study has been published in BMC Medicine. Reducing visceral fat is considered the true goal of weight loss as it is a more important indicator than a person's weight or the circumference of their waist. Visceral fat aggregates over time between organs and produces hormones and poisons linked to heart disease, diabetes, dementia, and premature death.

The research was led by Prof. Iris Shai of Ben-Gurion University of the Negev, Israel, an adjunct Professor from the Harvard School of Public Health, and an Honorary Professor, University of Leipzig, Germany, together with her doctoral student Dr. Hila Zelicha and Italian, German, and American colleagues.

The DIRECT-PLUS trial research team was the first to introduce the concept of the green-Mediterranean diet. This modified MED diet is further enriched with dietary polyphenols and lower in red/processed meat than the traditional healthy MED diet. On top of a daily intake of walnuts (28 grams), the participants consumed 3-4 cups of green tea/day and 100 grams (frozen cubes) of duckweed green shake/day. The aquatic green plant duckweed is high in bioavailable protein, iron, B12, vitamins, minerals, and polyphenols and substituted meat intake.

The team has shown in previous studies that the green MED diet has a variety of salutary effects ranging from the microbiome to age-related degenerative diseases.

Two hundred and ninety-four participants took part in the 18-month long trial.

"A healthy lifestyle is a strong basis for any weight loss program. We learned from the results of our experiment that the quality of food is no less important than the number of calories consumed and the goal today is to understand the mechanisms of various nutrients, for example, positive ones such as the polyphenols, and negative ones such as empty carbohydrates and processed red meat, on the pace of fat cell differentiation and their aggregation in the viscera," says Prof. Shai.

"A 14% reduction in visceral fat is a dramatic achievement for making simple changes to your diet and lifestyle. Weight loss is an important goal only if it is accompanied by impressive results in reducing adipose tissue," notes Dr. Hila Zelicha.

None of the funding providers was involved in any stage of the design, conduct, or analysis of the study and they had no access to the study results before publication.

Reference

Zelicha, H., Kloting, N., Kaplan, A. et al. The effect of high-polyphenol Mediterranean diet on visceral adiposity: the DIRECT PLUS randomized controlled trial. BMC Med 20, 327 (2022). https://doi.org/10.1186/s12916-022-02525-8