Green Mediterranean diets can significantly reduce body fat

Visceral fat, the dangerous fat surrounding your internal organs, is more harmful than excess weight on your waistline. Linked to heart disease, type 2 diabetes, dementia, and early death, this fat produces inflammatory chemicals and toxins that harm your health.

Researchers have now found a way to target it effectively: a modified version of the Mediterranean diet, enriched with plant-based polyphenols and low in red and processed meats.

A groundbreaking 18-month clinical trial, known as the DIRECT-PLUS study, tested how different diets reduce visceral fat.

Conducted by an international team led by Professor Iris Shai of Ben-Gurion University, the trial involved 294 participants, most of whom were middle-aged workers with abdominal obesity. The results showed that the "green Mediterranean diet" reduced visceral fat twice as effectively as the traditional Mediterranean diet.

The study divided participants into three groups. The first group followed a healthy diet with general nutritional guidelines and regular physical activity. The second group adhered to a classic Mediterranean diet with reduced carbohydrates. The third group followed the green Mediterranean diet, featuring high levels of polyphenols from green tea, walnuts, and duckweed shakes—a nutrient-dense aquatic plant. All three groups engaged in moderate exercise.

After 18 months, researchers used magnetic resonance imaging (MRI) to assess fat distribution. While participants in all groups lost weight, the green Mediterranean diet group achieved a remarkable 14% reduction in visceral fat. This compared to a 7% reduction with the traditional Mediterranean diet and a 4.5% reduction with a standard healthy diet.

“A 14% reduction in visceral fat is a dramatic achievement,” said Dr. Hila Zelicha, a key researcher on the study. “Weight loss is important, but only if it’s accompanied by significant reductions in harmful fat stores.”

Visceral fat accumulates deep within the abdomen, between internal organs, and is considered more dangerous than subcutaneous fat—the fat stored under your skin. Unlike subcutaneous fat, visceral fat secretes hormones, inflammatory substances, and toxins that increase the risk of cardiovascular disease, fatty liver disease, sleep apnea, and even some cancers.

What makes the green Mediterranean diet so effective? Researchers point to polyphenols—naturally occurring compounds found in plants. Polyphenols act as antioxidants and anti-inflammatories in the body. They may prevent fat cell growth, improve energy expenditure, and reduce fat storage.

Foods like green tea, walnuts, olive oil, fruits, and vegetables are rich in these compounds. Duckweed, a highlight of this study, is particularly nutrient-dense, providing plant-based protein, vitamins, minerals, and polyphenols.

“We learned that the quality of food matters as much as calorie intake,” said Professor Shai. “Polyphenols appear to positively influence fat cell behavior, while red and processed meat, along with refined carbohydrates, negatively impact fat storage.”

Previous studies had already suggested the Mediterranean diet’s benefits for metabolic health, reducing obesity-related conditions like hypertension and insulin resistance. However, this trial emphasized visceral fat reduction as a critical target for improving long-term health. By doubling the intake of polyphenols and lowering red meat consumption, the green Mediterranean diet accelerated fat loss in this high-risk group.

The DIRECT-PLUS trial builds on earlier research that demonstrated the Mediterranean diet’s effectiveness. The CENTRAL study, published in 2017, was one of the first to show that a Mediterranean diet with reduced carbohydrates outperformed low-fat diets for reducing visceral fat. DIRECT-PLUS took those findings further by enhancing the diet with polyphenols.

“People often try extreme measures to lose belly fat—starvation diets, intense workouts, even surgery,” said Professor Shai. “Our findings highlight the power of a simple, sustainable dietary change.”

Participants on the green Mediterranean diet consumed 28 grams of walnuts daily, three to four cups of green tea, and 100 grams of a duckweed shake. These additions provided an abundance of polyphenols while replacing red and processed meats. Notably, the diet’s plant-based focus aligns with broader health and environmental goals.

The trial’s success underscores a shift in how researchers and doctors approach weight loss. Visceral fat—not body weight or waist circumference—is emerging as the most important marker of metabolic health. Its reduction directly lowers the risk of chronic diseases, including cardiovascular issues and dementia.

MRI scans revealed not only reductions in visceral fat but also improvements in other fat stores. Participants experienced significant reductions in deep subcutaneous fat, another harmful fat layer linked to obesity and insulin resistance. These changes occurred independently of total weight loss, suggesting the green Mediterranean diet’s unique metabolic benefits.

Funding for the study came from respected organizations, including the Deutsche Forschungsgemeinschaft, the Israel Ministry of Health, and the California Walnuts Commission. However, none of the funders influenced the study’s design, conduct, or analysis.

The findings are especially relevant as diets rich in processed foods, sugars, and red meats have become widespread, even in regions like the Mediterranean. These dietary habits have contributed to rising rates of obesity and metabolic disorders worldwide. Returning to a plant-forward diet—one rooted in traditional eating patterns—may offer a practical and sustainable solution.

For those seeking to improve their health, the green Mediterranean diet presents a compelling approach. It emphasizes whole, nutrient-rich foods while minimizing harmful dietary components. By incorporating foods high in polyphenols, you can target visceral fat, improve metabolic health, and reduce your risk of chronic diseases.

“This research highlights how simple dietary changes can yield powerful results,” said Professor Shai. “A healthy lifestyle—one that prioritizes food quality over quantity—is the key to long-term success.”

If you’re struggling with stubborn belly fat or want to lower your risk of heart disease and diabetes, the green Mediterranean diet offers a scientifically proven path forward. With its focus on nutrient-dense plants, moderate exercise, and reduced red meat intake, this diet helps you achieve meaningful fat loss while supporting overall health.

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