A new large-scale clinical intervention trial found that a modified Mediterranean diet — called the green Mediterranean diet — is more effective at reducing visceral fat that can surround and damage organs than the standard Mediterranean diet or a generally healthy diet.
All three diets resulted in a reduction of visceral fat, but the green Mediterranean diet doubled the benefit of the “traditional” Mediterranean diet.
The study was conducted by the DIRECT-PLUS trial research team. It was led by Prof. Iris Shai of Ben-Gurion University of the Negev, Israel, and Dr. Hila Zelicha, now at the University of California, Los Angeles, aided by colleagues from Italy, Germany, and the United States.
The study appears in BMC Medicine.
The green Mediterranean diet
The green Mediterranean diet differs from the original Mediterranean diet in its emphasis on polyphenols.
Polyphenols are plant compounds that have been linked to protection from type 2 diabetes, some cancers, and heart disease. They also appear to support brain health and digestion.
Polyphenols are found in dark chocolate, berries, red wine, and tea, as well as some nuts, such as walnuts.
On the green Mediterranean diet, as envisaged in this study, a person consumes 28 grams of walnuts — about seven nuts — 3 to 4 cups of green tea, and 100 milligrams of the aquatic plant Wolffia globosa (Mankai) — also known as “duckweed” — in a smoothie or shake each day. All are rich in polyphenols.
Otherwise, the diet is the same as the original Mediterranean diet, but without the consumption of red and processed meats.
For the 18-month randomized controlled trial, researchers divided the 294 participants into three groups:
- one group followed a standard Mediterranean (MED) diet
- one followed a green Mediterranean (green-MED) diet
- a final group one strictly followed healthy dietary guidelines (HDG).
All groups were offered lifestyle educational sessions and physical activity recommendations, along with a free gym membership.
Researchers supplied the walnuts, tea, and Mankai, along with recipes for green smoothies.