Reduce visceral fat… by eating. No, it is not an impossible wish but the result of a scientific study published a few days ago in the Journal of Clinical Endocrinology & Metabolism thanks to the work of an Israeli team in collaboration with the prestigious Harvard T.H. Chan School of Public Health in Boston (Tsaban et al, J Clin Endocrinol Metab, 2021).
The role of ghrelin
Ghrelin is a hormone produced by stomach cells, able to stimulate appetite and to regulate metabolism, body weight and insulin sensitivity. Ghrelin increases after an overnight fast and decreases after each meal. Well, it has been observed that a healthy diet increases fasting ghrelin levels and that an increase in fasting ghrelin levels is associated with a reduction in visceral fat and an improvement in insulin sensitivity, with a lower risk of suffering from cardiovascular disease and diabetes.
The experiment
But what is meant by a healthy diet? To answer this question, scientists performed a study. In particular, nearly 300 volunteers were recruited, all overweight and with a high cholesterol condition. The study participants were divided into three groups. The first group was asked not to follow a particular diet but to adhere to a varied and balanced diet, the second group followed the guidelines of the Mediterranean diet while the third group a modified version of the Mediterranean diet, called the green Mediterranean diet. The normal Mediterranean diet, which we all know, is based on a regular intake of fruit, vegetables, whole grains, nuts and legumes, a moderate intake of dairy products, fish and poultry and a low consumption of processed meat and sweets. The green version of the Mediterranean diet involves the complete elimination of red meat and the introduction of 3-4 cups a day of green tea and a vegetable smoothie containing mankai, or duckweed, considered the new protein-rich superfood. Both versions of the Mediterranean diet also included 28 grams of nuts per day. Along with the diet, all volunteers were asked to exercise regularly. The study lasted 18 months and at the beginning and at the end the volunteers underwent blood tests and magnetic resonance imaging to assess the levels of ghrelin, blood sugar and the amount of visceral fat.
The Mediterranean diet helps reduce visceral fat, conclusions
After 18 months, what emerged is that all diets led to an increase in fasting ghrelin values. However, differences were observed. Those who followed a varied and balanced diet had a very small increase, around 1%, in ghrelin. A significant increase was instead observed with the Mediterranean diet. The traditional version resulted in a 5% increase in fasting ghrelin while the green version of the Mediterranean diet resulted in a 10% increase, making it the most efficient. In addition, insulin sensitivity and visceral fat were inversely proportional to fasting ghrelin levels. Therefore, the Mediterranean diet, especially in its green version, stimulates higher loss of visceral fat and improves metabolic parameters resulting more cardioprotective and more powerful to reduce the risk of developing cardiovascular disease and diabetes.
