Overview: A modified version of the Mediterranean diet called the green Mediterranean diet, which consists of fortified dietary polyphenols such as green tea, walnuts, and duckweed, and less red meat, reduced more visceral fat than the traditional Mediterranean diet or a traditional diet plan.
Source: Ben-Gurion University of the Negev
The green Mediterranean diet (MED) significantly reduces visceral adipose tissue, a type of fat around internal organs that is much more dangerous than the extra “band” around your waist.
The green Mediterranean diet was pitted against the Mediterranean diet and a healthy diet in a large-scale clinical intervention trial – the DIRECT PLUS. Later analysis showed that the green Med diet reduced visceral fat by 14%, the Med diet by 7% and the healthy diet by 4.5%.
The study is 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 waist circumference. Visceral fat accumulates between organs over time, producing hormones and toxins linked to heart disease, diabetes, dementia and premature death.
The research was led by Prof. Iris Shai from 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, along 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 contains less red/processed meat than the traditional healthy MED diet. In addition to a daily intake of walnuts (28 grams), the participants consumed 3-4 cups of green tea/day and 100 grams (frozen cubes) of green duckweed shake/day. The duckweed of the aquatic green plant is high in bioavailable protein, iron, B12, vitamins, minerals and polyphenols and substitute meat intake.
The team has shown in previous studies that the green MED diet has a variety of beneficial effects ranging from the microbiome to age-related degenerative diseases.
Two hundred and ninety-four participants participated in the 18-month trial.
“A healthy lifestyle is a strong foundation for any weight loss program. We have 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 different nutrients, for example positive ones such as the polyphenols, and negative ones such as empty carbohydrates and processed red meat, on the rate of fat cell differentiation and their aggregation in the gut,” 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 only an important goal if it is accompanied by impressive results in reducing fat tissue,” notes Dr. Hila Zelicha.
financing: This work was funded by grants from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) – Project Number 209933838- SFB 1052; the Rosetrees trust (grant A2623); Israel Ministry of Health grant 87472511; Israel Ministry of Science and Technology grant 3-13604; and the California Walnuts Commission.
None of the funders were involved in any phase of the study’s design, conduct or analysis, and they had no access to the study results prior to publication.
About this news about nutrition and fat reduction research
Author: Ehud Zion Waldoks
Source: Ben-Gurion University of the Negev
Contact: Ehud Zion Waldoks – Ben-Gurion University of the Negev
Image: The image is in the public domain
Original research: Open access.
“The effect of a high polyphenol Mediterranean diet on visceral adiposity: the DIRECT PLUS randomized controlled trial” by Hila Zelicha et al. BMC medicine
The effect of a high polyphenol Mediterranean diet on visceral adiposity: the DIRECT PLUS randomized controlled trial
Mediterranean (MED) foods are a rich source of polyphenols, which benefit obesity in several ways. We investigated the effect of the green MED diet, twice enriched with dietary polyphenols and less red/processed meat, on visceral adipose tissue (VAT).
In the 18-month Dietary Intervention Randomized Controlled Trial PoLyphenols Unprocessed (DIRECT-PLUS) Weight Loss Study, 294 participants were randomized to (A) healthy eating guidelines (HDG), (B) MED, or (C) green-MED diets, all combined with fysical activity. Both isocaloric MED groups consumed 28 g/day of walnuts (+ 440 mg/day of polyphenols). The green-MED group also consumed green tea (3-4 cups/day) and Wolffia globosa (duckweed variety) plant green shake (100 g frozen cubes/day) (+ 800 mg/day polyphenols) and reduced intake of red meat. We used magnetic resonance imaging (MRI) to quantify the abdominal adipose tissues.
Participants (age = 51 years; 88% men; body mass index = 31.2 kg/m2; 29% VAT) had a retention rate of 89.8% and 79.3% completed eligible MRIs. While both MED diets achieved similar moderate weight loss (MED: -2.7%, Green-MED: -3.9%) and waist circumference (MED: -4.7%, Green-MED: -5.7%) , the green-MED dieters doubled their VAT loss (HDG: − 4.2%, MED: − 6.0%, green-MED: − 14.1%; p < 0.05, independent of age, gender, waist circumference or weight loss). Higher dietary consumption of green tea, walnuts and Wolffia globosa; lower intake of red meat; higher total plasma polyphenols (mainly hippuric acid), and increased urine urolithin A polyphenol were significantly related to greater VAT loss (p < 0.05, multivariate models).
A green MED diet, enriched with plant polyphenols and less red/processed meat, can be a powerful intervention to promote the regression of visceral adiposity.