After having four babies, many individuals explore various methods to lose weight, ranging from shake diets to rigorous exercise programs. In recent years, dietary supplements have surged in popularity, with some boasting incredible weight loss powers. One such supplement, currently under investigation, involves the use of freeze-dried poop capsules. While the concept may seem unconventional, it's rooted in the growing understanding of the gut microbiome's influence on body weight.
The Gut-Weight Connection: A New Frontier in Weight Loss
The foundation of this approach lies in the idea that the gut bacteria of a lean individual could potentially aid an obese person in losing weight. This isn't an entirely novel concept. There's growing evidence indicating that gut bacteria significantly influences body weight. Studies suggest a connection between healthy gut bacteria and a slimmer waistline.
Research published in the International Journal of Obesity suggests that weight regulation isn't solely about fiber intake. According to lead author Arne Astrup, "Certain bacterial species play a decisive role in weight regulation and weight loss. Now we can explain why a high fiber diet does not always lead to weight loss. Human intestinal bacteria is an important part of the answer and will from now on play a role in the treatment of the overweight."
Fecal Microbiota Transplantation (FMT): Poop Pills and Beyond
Oral fecal transplants have shown promise in mice, according to the journal Science. Some studies published in 2013 indicated that diverse gut bacteria are beneficial in establishing a healthy weight. Researchers at Massachusetts General Hospital in Boston are conducting trials to assess the impact of ingesting human poop from lean individuals on obese individuals. Participants in these trials ingest freeze-dried fecal samples in pill form over a six-week period. The goal is to replace an obese person's intestinal microbes with those from a healthier individual. Participants are monitored for 12 months to measure weight loss results compared to those who took placebos.
Elaine Yu, an assistant professor and clinical researcher at Massachusetts General Hospital, acknowledges the uncertainty surrounding the outcome but hopes that microbe treatment could complement other dietary interventions for obesity.
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Autologous Fecal Microbiota Transplantation (aFMT) and the Green-Mediterranean Diet
A study explored autologous fecal microbiota transplantation (aFMT), where participants received their own fecal microbiota after a period of weight loss. After a 6-month weight loss phase, 90 qualified members provided a fecal sample that was prepared into autologous fecal microbiota transplantation (aFMT) by frozen, opaque, and odorless capsules. The study also incorporated a green-Mediterranean diet, where participants were provided with Mankai, a specific duckweed aquatic strain in a green shake, green tea, and 28g of walnuts. The 90 participants lost 8.3 kg (18.2 lbs.) on average after six months.
Dr. Rinott E et al. suggest that this is the first study that shows the preservation of an “ideal” gut microbial composition can be utilized at a later point to accomplish metabolic advantages. Dr. Also, a green plant-based eating regimen, such as Mankai, better improves the microbiome for the microbiota transplantation system. According to Prof. Koren, “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. BGU Prof. Iris Shai said, “These findings might be a good application of personalized medicine. Freezing a personal microbiome bank could be an effective way to maintain a healthy weight while dieting since the rapid weight loss phase is accompanied by optimal cardiometabolic health.
Gut Bacteria Species and Weight Regulation: Prevotella vs. Bacteroides
Research has identified two key species of gut bacteria, Prevotella and Bacteroides, that influence weight gain or loss and overall physiology. These bacteria work together to digest fiber, and individuals have varying amounts of each. A study involving participants on the new Nordic diet, rich in fiber, fruits, and vegetables, revealed that the diet was most effective for those with higher levels of Prevotella/Bacteroides. These individuals experienced greater waistline reduction and body fat loss compared to those with lower levels.
This suggests that the effectiveness of a diet may depend on an individual's unique gut bacteria composition. As the authors of the study concluded, not every diet works for everyone, and understanding individual biochemistry is crucial for determining the best weight loss approach.
The Role of Meal Replacement Shakes in Weight Loss
Meal replacement shakes are often used for quick meals or as a weight loss strategy. These shakes are designed to replace breakfast, lunch, or dinner, providing nutrients with fewer calories than a typical meal. They are often high in protein, which aids in appetite management.
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Benefits of Meal Replacement Shakes
- Nutrient-Rich: Meal replacement shakes can provide a healthy option when time is limited, ensuring adequate nutrient intake.
- Low Calorie: These shakes can be a valuable addition to a weight loss plan, helping to reduce calorie intake without sacrificing essential nutrients.
- Added Fiber: Many meal replacement shakes are high in fiber, promoting healthy digestion and preventing bloating or constipation.
- Proven Weight Loss: Studies have shown that incorporating meal replacement shakes into a diet can lead to significant weight loss compared to traditional dieting methods.
Potential Drawbacks
- Artificial Ingredients: Many meal replacement shakes contain artificial ingredients, including added sugars, to enhance flavor and preserve the product. It's important to carefully read labels.
- Low Calorie Intake: While beneficial for weight loss, the low calorie content of meal replacement shakes (typically 150-200 calories) may require supplementation with other meals and snacks to meet daily caloric needs.
- Allergen Concerns: Individuals with dairy allergies or lactose intolerance should check labels for potential allergens.
The Power of Fiber: Soluble vs. Insoluble
Fiber, a carbohydrate that the gut cannot digest, plays a crucial role in weight management and overall health. There are two main types of fiber: soluble and insoluble.
- Insoluble Fiber: Primarily acts as a bulking agent, adding content to the stool.
- Soluble Fiber: Has a significant impact on health, metabolism, and weight, and can be fermented by gut bacteria.
Soluble Fiber and Gut Bacteria: A Symbiotic Relationship
Soluble fiber serves as food for beneficial gut bacteria, also known as the gut flora or gut microbiome. These bacteria play a vital role in various aspects of health, including:
- Weight management
- Blood sugar regulation
- Immunity
- Brain function
The fiber that nourishes gut bacteria is called prebiotic fiber or fermentable fiber, which is highly beneficial for health and body weight.
The Impact of Fiber on Inflammation
Gut bacteria have a well-established effect on chronic inflammation. While short-term inflammation is essential for fighting infections and repairing tissues, chronic inflammation can lead to various health problems, including:
- Cancer
- Alzheimer's disease
- Metabolic syndrome
Studies have shown that a high fiber intake is associated with lower levels of inflammatory markers in the bloodstream.
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Fiber and Appetite Suppression: Achieving a Calorie Deficit
To lose weight, a calorie deficit is necessary, meaning burning more calories than consumed. Fiber, particularly viscous soluble fiber, can help reduce appetite, making it easier to achieve a calorie deficit without constant calorie counting.
Viscous soluble fibers, such as pectins, beta-glucans, psyllium, glucomannan, and guar gum, thicken in water, forming a gel-like substance in the gut. This gel slows stomach emptying, increasing digestion and absorption times, resulting in a prolonged feeling of fullness and reduced appetite.
Sources of Viscous Fiber
Viscous fibers are found exclusively in plant foods. Rich sources include:
- Beans and legumes
- Flaxseeds
- Asparagus
- Brussels sprouts
- Oats
When transitioning to a high fiber diet, it's important to do so gradually to allow the body to adjust and to increase water intake to aid digestion.
Fiber Supplements: A Closer Look
Fiber supplements are typically made by isolating fiber from plants. While they may offer some health benefits, the evidence for weight management is mixed. One exception is glucomannan, a fiber extracted from the konjac root, which has shown promise for weight reduction in adults with overweight and obesity.
However, it's important to remember that supplementing with isolated nutrients alone may not be sufficient. Combining fiber supplements with other weight loss strategies is often more effective.
Fiber Supplements in the Large Bowel
There are 2 mechanisms by which fiber supplements can improve constipation: (1) mechanical stimulation/irritation of the colonic mucosa and (2) gel-dependent/viscous water-holding capacity that resists dehydration. The first mechanism is mechanical stimulation/irritation of the gut mucosa by the particles of insoluble fiber. The mechanical stimulation/irritation results in secretion of mucous and water, resulting in larger/softer stools and faster transit through the large bowel. This mechanism is proportional to particle size and shape-large coarse particles have a significant laxative effect, whereas small smooth particles do not.
Insoluble fiber has no water-holding/gel-forming capacity, so insoluble fiber supplements cannot be of benefit for attenuating loose/liquid stools in diarrhea. The second mechanism is high water-holding capacity that resists the water-absorbing/dehydrating effects of the large bowel. Nonviscous soluble fibers, like wheat dextrin and inulin, are fermented (not present in stool throughout the large bowel) and have no water-holding capacity and thus do not provide a laxative benefit at physiologic doses. In contrast to the fiber supplements discussed above, psyllium is not fermented in the gut and retains its water-holding gelled structure throughout the large bowel.
Fiber and Weight Loss/Maintenance
A high level of dietary fiber consumption (eg, replacement) has been associated with a 30% reduction in the risk of gaining weight or developing obesity. Gel-forming fibers may influence satiety by several mechanisms, including delayed degradation and absorption of nutrients in the small bowel, leading to a “sustained” delivery of nutrients, and delivery of nutrients to the distal ileum with subsequent stimulation of feedback mechanism like the “ileal brake” phenomenon (slows gastric emptying and small bowel transit) and decreased appetite. Satiety is often assessed in short-term clinical studies as a tool or mechanism for predicting the potential for decreased energy intake and weight loss, but the end therapeutic goal is weight loss (or prevention of weight regain).
A 6-month study compared the effects of viscosity on weight loss by assessing a viscous, gel-forming, nonfermented fiber (psyllium) versus a less viscous, readily fermented fiber (partially hydrolyzed guar gum). The control group showed gradual loss in weight over the first 4 months, followed by weight regain. After 2 months, the guar gum treatment group showed a marked weight reduction, but this reversed to weight regain over the following 4 months. In contrast, the psyllium treatment group showed gradual and sustained weight loss across the entire 6-month test period.
It is worth noting that the gel-forming fibers in the study above also improved other objective clinical measures of metabolic syndrome. After 6 months of treatment, both the psyllium and guar gum treatment groups showed significant improvement in fasting plasma glucose, fasting plasma insulin, hemoglobin A1c, and low-density lipoprotein (LDL) cholesterol. Only the psyllium group exhibited a significant improvement in plasma triglyceride concentration and systolic and diastolic blood pressure.
The Importance of Fiber Processing
Although it has been clearly shown that raw gel-forming fibers (eg, guar gum, high-molecular-weight β-glucan) can exhibit significant health benefits, it is important to consider how the degree of processing to make a final marketed product may alter the viscosity/gelling capacity of a fiber supplement. For example, 2 clinical studies investigated the effects of β-glucan from oat bran, either baked into bread and cookies (study 1) or provided as a raw fiber in orange juice (study 2), on serum cholesterol concentrations in 48 subjects with hypercholesterolemia. The β-glucan baked into bread and cookies had no effect on serum LDL-cholesterol (not different from negative control). In contrast to these results, study 2 provided a lower dose of β-glucan in orange juice, which significantly decreased LDL-cholesterol concentration versus the wheat fiber control.
The viscosity of the β-glucan was altered by the degree of processing (heat and pressure) to which the fiber was exposed in making the cereal. The results showed that cholesterol lowering was highly correlated with the viscosity of the β-glucan: High viscosity (lower heat and pressure) was correlated with significant cholesterol lowering; low viscosity (higher heat and pressure) was correlated with diminished cholesterol lowering.
Tips for Fiber Supplement Use
For a simple and reasonable test to determine if a fiber supplement can provide gel-dependent health benefits, stir a single dose of the marketed product (usually 2-4 g of fiber) into 120 mL of water and let it stand for 15 minutes. Sensations of slight discomfort to cramping pain may be associated with an increase in consumption of dietary fiber, particularly if the patient is constipated and/or a fiber supplement is initiated at a relatively high dose. To facilitate long-term compliance with a fiber supplement regimen, it is important to minimize significant differences in stool viscosity.
For nonconstipated subjects, this entails starting a new fiber supplement gradually, initiating dosing at no more than 3 or 4 g/d the first week, then increasing very gradually over subsequent weeks with a goal of about 10 to 15 g/d. For constipated patients, any introduction of a new fiber regimen carries a significant risk of cramping pain unless the hard stool is eliminated first. A reasonable suggestion is to first clear the hard stool from the bowel with a significant dose of an osmotic laxative (eg, polyethylene glycol). Once the hard stool is cleared, gradually introduce a new fiber supplement as above.