By some estimates, eight out of 10 of people who manage to lose at least 10% of their body weight will gradually regain it to end up as heavy or even heavier than they were before they went on a diet. It seems that even though metabolism slows down after weight loss, out-of-control appetites are the reason why so many people regain weight after they’ve worked so hard to lose it; they get really hungry after losing weight and eat more.
But hope is offered by a team of researchers at Ben-Gurion University of the Negev (BGU) in Beersheba and colleagues abroad. In an unprecedented, 14-month clinical trial in Israel, Dr. Iris Shai, BGU doctoral student Dr. Ehud Rinott and Dr. Ilan Youngster from Tel Aviv University, collaborated with a group of international experts from US and European research institutes.
They found that people who consume sterilized, frozen microbiome capsules derived from their own feces – bacteriotherapy –when dieting can limit their weight regain. They just published their findings in the prestigious journal Gastroenterology under the title “Effects of Diet-Modulated Autologous Fecal Microbiota Transplantation on Weight Regain.”
“It is well known that most weight-loss dieters reach their lowest body weight after four to six months and are then challenged by the plateau or regain phase, despite continued dieting,” noted Shai of BGU’s School of Public Health. In this seminal study, the international group of researchers explored whether preserving the optimized personal microbiome from fecal transplants after six months of weight loss helps maintain weight loss by transplanting back the optimized microbiome during the subsequent expected regain phase.
Fecal transplants performed by gastroenterologists involves the transplants of clean, processed feces via an oral capsule from a healthy donor into another person or from the same person to himself to restore the balance of bacteria in their gut. Such transplants can help treat or even cure chronic infections in the colon, such as C. difficile-associated disease, in the US alone kills about 15,000 people each year.
In the BGU weight-loss trial, Israeli patients who are abdominally obese or have high levels of blood cholesterol) participants were randomly assigned to one of three groups – whose who observed healthful dietary guidelines; those who ate a Mediterranean diet, and those who ate a “green-Mediterranean diet.”
After six months during the weight-loss phase, 90 eligible participants provided a fecal sample that was processed into freeze-dried, opaque and odorless capsules. The participants were then randomly assigned to the groups that received 100 capsules containing their own fecal microbiota or placebo which they ingested until month 14.
In the green-Mediterranean diet group, participants were provided with mankai – an ancient green duckweed that’s revolutionizing the future of plant-based, sustainable food, the world’s only plant source that contains complete protein with all nine essential amino acids, iron, and vitamin B12 –in a green shake, with green tea and 28 grams of walnuts. This was the group diet strategy that induced the largest significant change in the gut microbiome composition during the weight loss phase.
The 90 participants lost 8.3 kg (18.2 lbs.) on average after six months, However, only in the green-Mediterranean diet group did the fecal capsule limit weight regain from only 17.1%, vs 50% for the placebo.
“The green-Mediterranean diet also resulted in preservation of weight loss-associated specific bacteria and microbial metabolic pathways, mainly glucose transport, following the microbiome intervention, compared to the control,” declared Rinott.
In a complementary mankai-specific mouse model experiment conducted by Prof. Omry Koren at Bar-Ilan University in Ramat Gan near Tel Aviv, the researchers were able to reproduce the effects of fecal transplantation on weight regain and insulin sensitivity and to isolate the specific contribution of mankai consumption to induce these effects.
“This study is the first of its kind to prove in humans that preservation of an “ideal” gut microbial composition can be used at a later time point to achieve metabolic benefits,” said Youngster, director of the pediatric infectious diseases unit and the Center for Microbiome Research at Shamir Medical Center in Tzrifin near Rishon Lezion. “Using the patient’s own stool after optimization is a novel concept that overcomes many of these barriers. It is my belief that the use of autologous [from the same person] fecal microbiota transplantation will be applicable in the future for other indications as well.”
In addition, green plant-based diet such as mankai optimizes the microbiome for the microbiota transplantation procedure even more. This potentially optimizes the conditions for fecal material collected during the maximal weight-loss phase. The mankai duckweed aquatic plant is being grown in Israel and other countries in a closed environment and is highly environmentally sustainable, requiring a fraction of the amount of water to produce each gram of protein compared to soy, kale or spinach.
According to Koren, who led the animal experiments, “the nutrition-microbiome axis has been proven in this study as high polyphenols diet, and specifically, mankai, a protein-based plant and dietary fibers could ideally optimize the microbiome in the weight loss phase to induce potent microbiome to recall the flora of germs related to regain attenuation and improved glycemic state after transplantation.”
“These findings might be a good application of personal medicine,” concluded Shai who is also an adjunct professor at Harvard. “Freezing a personal microbiome bank could be an effective way to maintain healthy weight while dieting as the rapid weight loss phase is accompanied by optimal cardiometabolic state. By optimizing the composition and function of the gut microbiome within the host, we have a novel approach for metabolic-memory preservation: taking a sample of the gut microbiome in its ideal phase, and administrating it when dieters start regaining their lost weight.”
The research was supported by the Israeli Science Foundation, Israel’s Health Ministry, Israelis Science and Technology, the German Research Foundation and others.