Live in Israel, want to lose weight? Return to Mediterranean diet - study

Prof. Iris Shai: We learned from the results of the experiment that the quality of the food is just as important as the total number of calories consumed.

A healthy Mediterranean meal (photo credit: INGIMAGE)
A healthy Mediterranean meal
(photo credit: INGIMAGE)

What do people – both women and men – do to get rid of their belly fat? Starvation diets, regular workouts in the gym, belly wraps, pills, liposuction, plastic surgery and more.

But as Israelis live in the eastern Mediterranean, if they want to minimize their intra-abdominal (visceral) fat, they would be well advised to abandon sweets, salty snacks and highly processed foods that they have adopted in recent years and return to the traditional diet of this region.

A new and unusual Israeli clinical trial that continued over a particularly long period of time among hundreds of subjects used the magnetic resonance imaging (MRI) device to map the accumulation of excess fat in different areas of the human body and to examine the most effective nutritional strategies for reducing intra-abdominal fat in the abdomen (what we call belly fat).

The study was published in the medical journal BMC Medicine under the title “The effect of high-polyphenol Mediterranean diet on visceral adiposity: the DIRECT PLUS randomized controlled trial.”

 Prof. Iris Shai (credit:  Dani Machlis/BGU) Prof. Iris Shai (credit: Dani Machlis/BGU)

Studying the Mediterranean diet?

Reducing intra-abdominal (visceral) fat is a main goal in the weight loss process due to it being a more accurate health marker than body weight or abdominal circumference. The deep intra-abdominal fat that accumulates over the years between the internal abdominal organs is considered more toxic compared to the subcutaneous fat stores.

This tissue differs in color, size and composition of its fat cells and secretes inflammatory substances, hormones and toxins associated with an increase in the incidence of cardiovascular diseases, diabetes, fatty liver disease, polycystic ovary syndrome and dementia. The condition also raises the risk of sleep apnea, joint pain and various forms of cancer.

RESEARCHERS FROM Ben-Gurion University of the Negev in Beersheba (BGU), in collaboration with the Nuclear Research Center in Dimona (KMG), Soroka University Medical Center Hospital, experts from the universities of Harvard in Massachusetts and Leipzig in Germany tested different types of diets on a research group of about 300 participants and discovered that a green Mediterranean, diet low in carbohydrates and in red meat and in combination with moderate physical activity, accelerates the reduction in intra-abdominal fat twice.

In an intensive experiment that lasted for a year and a half, the researchers used MRI technology to accurately assess the changes in fat stores, and the effect of three different treatments among the participants, all of whom were workers at the Dimona nuclear reactor suffering from abdominal obesity.

The first treatment consisted of a healthy diet with basic nutritional guidelines and physical activity, the second treatment consisted of a classic Mediterranean diet with reduced carbohydrates and physical activity and the third treatment consisted of a green Mediterranean diet doubled in the amount of polyphenols (from green plants) with moderate physical activity, reduced carbohydrates and low red/processed meat.

At the end of 18 months and the persistence of more than 85% of the participants in the various protocols of the experiment, it was found that despite a similar loss in weight and waist size with the two Mediterranean diets, the green Mediterranean diet protocol accelerated the decrease of intra-abdominal fat more than twice as fast as the classic Mediterranean diet protocol (14% reduction compared to 6%)  The researchers identified specific polyphenolic compounds in the blood and urine of the subjects given the green diet that were associated with a decrease in this toxic fat.

The clinical trial was conducted under the leadership of BGU nutrition and epidemiology Prof. Iris Shai, who is also an adjunct professor at Harvard University and an honorary professor at the University of Leipzig, together with her doctoral student Dr. Hila Zelicha and Italian, German and American colleagues.

The trial was a continuation of the findings of the previous clinical trial reported about in 2017 in the journal Circulation, in which the researchers reported for the first time from the CENTRAL study on the increased effectiveness of a classic Mediterranean diet with reduced carbohydrates in reducing intra-abdominal fat compared to a low-fat diet that was accepted by the medical unions at the time.

IN THE new experiment, as mentioned, the researchers challenged their previous findings by doubling the number of polyphenols from the plant provided to the subjects and by reducing the red and processed meat. Polyphenols are organic compounds, secondary products of plant foods that are intended to protect the plant itself, and are increasingly distinguished as having a beneficial effect as antioxidants and anti-inflammatories in the human body. Various polyphenols are found in green tea, green plants, coffee, olive oil, red wine, nuts, fruits and vegetables.

“A healthy lifestyle is the solid foundation for any course of weight loss,” said Shai. “We learned from the results of the experiment that the quality of the food is just as important as the total number of calories consumed… the goal in the future is to understand the mechanisms of influence of various molecules, such as polyphenols (positively) and unnecessary carbohydrates and red and processed meat (negatively) on the rate [of fat loss and] the differentiation of the fat cells and their storage in the deep intra-abdominal fat tissue and in other toxic reservoirs.”

“We learned from the results of the experiment that the quality of the food is just as important as the total number of calories consumed… the goal in the future is to understand the mechanisms of influence of various molecules, such as polyphenols (positively) and unnecessary carbohydrates and red and processed meat (negatively) on the rate [of fat loss and] the differentiation of the fat cells and their storage in the deep intra-abdominal fat tissue and in other toxic reservoirs.”

Prof. Iris Shai

Zelicha added that “a reduction of 14% of the total intra-abdominal fat is a dramatic achievement while taking simple measures to only change the lifestyle – and that weight loss is an important goal, but only if it is accompanied by impressive results in reducing the dangerous fat stores.”