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A 'green' Mediterranean diet could lead to more weight loss, study finds

The Mediterranean diet is regarded as one of the healthiest diets to follow, but what happens when you follow a "greener" version of it?
Green Med Diet Square
People following the "green" Mediterranean diet ate higher quantities of plant matter, including 100 grams of frozen cubes of wolffia globosa, a plant-based protein, in a shake as a substitute for meat.

A “greener” form of the Mediterranean diet that contains more plant matter and far less red meat and poultry than the traditional version, may be even more heart healthy, especially in men, according to a study published Monday in the journal Heart.

The original version of the diet has been linked in numerous studies to a lower risk of coronary heart disease, stroke and diabetes. Its impact is thought to be related to higher dietary intake of fruits, vegetables and whole grains, and a lower intake of red meat.

“The main message of this study is that a Mediterranean diet further restricted in red meat consumption and with a parallel increase in green-plant–based protein with high polyphenol and phytosterols content may provide greater cardiometabolic protection compared to a healthy Mediterranean diet and it will aid in reducing LDL-cholesterol,” said study co-author Iris Shai, a professor of epidemiology and public health at Ben-Gurion University of the Negev in Beersheba, Israel and an adjunct professor at the Harvard T.H. Chan School of Public Health in Boston.

“This was especially remarkable in the unusual and significant 4% reduction in 'bad' cholesterol (LDL) and a 20% regression in low-grade systemic inflammation,” Shai said in an email.

To explore whether the green form of the Mediterranean diet might be superior to the original, Shai and her colleagues rounded up 294 sedentary and moderately obese adults whose average age was 51 and randomly assigned them to one of three groups.

The first group received guidance on boosting physical activity and achieving a healthful diet; the second, got the same encouragement to increase physical activity plus advice on following the traditional Mediterranean diet with calories restricted to 1,500 to 1,800 per day for men and 1,200 to 1,400 per day for women; and the third group received the same physical activity advice plus advice on following the green Mediterranean diet with the same calorie restrictions as the second group.

The third group was encouraged to avoid red and processed meats, to consume 28 grams/day of walnuts (about 7-8 walnuts), to drink three to four cups/day of green tea and to eat higher quantities of plant matter, including 100 grams of frozen cubes of wolffia globosa in a shake as a substitute for meat.

Wolffia globosa, also known as duckweed, “has been consumed as human food for hundreds of years, mainly in Laos, Vietnam and Thailand, where it is called ‘meat for the poor’ thanks to its high protein content,” Shai explained. You can buy it as a powder supplement or in frozen form.

When Shai and her colleagues compared the three groups they found that participants in both Mediterranean diet groups lost more weight than the healthy eating group. On average those on the green Mediterranean diet lost nearly 14 pounds (6.3 kg), those on the traditional Mediterranean diet lost nearly 12 pounds (5.4 kg), while those on the healthy diet lost just over three pounds (1.5 kg).

The participants on the green Mediterranean diet lost a little over 3 inches (8.6 cm) from their waists, as compared to just under 3 inches (6.8 cm) among those on the traditional Mediterranean diet and under 2 inches (4.3 cm) among those on the healthy diet. Participants on the green Mediterranean diet also saw bigger decreases in LDL cholesterol.

Those on the green Mediterranean diet also experienced larger improvements in blood pressure, insulin resistance and C-reactive protein, an important marker of inflammation.

While the green Mediterranean diet may appeal to some people, “I don’t think there are enough benefits over the traditional Mediterranean diet for everyone to do it,” said Julia Denison, clinical nutrition coordinator for UPMC Magee-Womens Hospital in Pittsburgh. “It would depend on the person. If a person was able to follow the traditional Mediterranean diet well and wanted to do more, then this might appeal to them.”

Denison was intrigued by the wolffia globosa. “What’s interesting is that it contains all nine amino acids,” she said. “A lot of plants don’t. You usually have to eat two together to achieve that, like rice and beans. It’s also really high in protein as compared to other plant sources.”