Is Weight Loss Linked to Gut Health

Everyone knows that adopting healthy eating habits and increasing physical activity are both effective ways to loss weight. What people might not know is that these behaviors can have a significant effect on the gut microbiome, which in turn supports weight loss through key microbial actions. Researchers have suggested that dietary and lifestyle recommendations for weight loss may include personalized recommendations based on an individual’s gut microbiota.

Human studies have observed that gut microbial composition varies between obese and lean individuals. Obese individuals have less microbial diversity in the gut, overall and more Firmicutes, which is a type of bacteria that can negatively affect fat and glucose metabolism. Obese individuals also have significantly less Bacteroidetes, which are favorable in the gut because they produce short-chain fatty acids that are associated with lower levels of inflammation and protection from obesity, than leaner individuals. When researchers observed differences in gut microbes, they realized it played a major role in many factors that affect a person’s weight, such as food cravings, hormones, and metabolic effects.

Let’s take a look at food cravings. Have you ever thought about where your food cravings come from? Whether you have the urge to snack on salty potato chips, or sweet chocolate ice cream may be a result of the microbes in your gut. This is because some microbes have the ability to control host behavior, which is the behavior of the organisms they inhabit. One study found that individuals who crave chocolate have certain microbial metabolites in their urine that individuals without chocolate cravings do not. Individuals with a diverse gut microbiome, which has been associated with a lower body weight, has less influence over host behaviors than a microbiome with less diversity because more energy is expended on competition between bacteria. When there is fewer varieties of bacteria in the gut, microbial populations manipulate host behavior in less favorable ways, such as cravings, to boost their own survival. It has been thought that gut microbes may influence taste receptors.

Let’s switch gears to hormones. Gut microbes can also affect hormones that alter hunger and satiety levels, such as leptin and ghrelin. This is thought to occur in one of two ways: through production of peptides that mimic hormones affecting satiety or making antibodies that can alter appetite directly. Studies have found that gut microbes can influence leptin, a hormone, that signals fullness and affects caloric expenditure. GLP-1, another hormone affected by the composition of the gut microbiome, is needed to send nutritional and energy status signals from the gut to the central nervous system in order to control food intake.

Gut microbes, not only influence what and how much we want to eat, but may also influence our caloric expenditure from these foods. Animal studies have found that microbe free mice weighed less than normal mice, even when they were fed the same diet. When microbes were transplanted into the microbe free mice, they gained weight, even though the diet wasn't changed. The transplanted microbes appeared to play a role in releasing calories from the diet and storing more energy and fat cells. Very few studies on these affects have been conducted in humans. This has been an exciting new area for future research. They found that lower levels of Bacteroidetes in the gut increased caloric harvest from the diet by 5% of total daily energy intake. They also found that the bacteria Akkermansia muciniphila is associated with lower levels of obesity, diabetes, and other metabolic disorders. Higher concentrations of A. muciniphila in the gut supports a healthy weight and supports the integrity of the mucus layer in the gut. Certain microbes may be responsible for these metabolic effects.

So what does all this mean? How can I support my gut health and weight loss? The key takeaway to all this information is finding a lifestyle that will support gut health, shift microbial composition in your favor and keep you feeling energized. There are several lifestyle factors that can do all that! You need to eat foods that encourage beneficial gut microbes, increase physical activity and be mindful of antibiotic use. Here are a few tips, and the science behind them, to help you nourish your gut microbes to achieve and maintain a healthy weight. First, crowd out high fat overly processed foods. Do you remember those gut bacteria names, Firmicutes and Bacteroidetes? The difference in these levels can play a role in body weight. When you have a higher caloric intake, especially from high fat, overly processed foods and high sugar diets, there is a loss of beneficial Bacteroidetes and an increase in Firmicutes, potentially resulting in obesity. When there is a healthy change in diet and weight, these bacterias will level out. Secondly, increase diversity with your fruits and vegetables. It has been shown that people who consume 30 or more types of plant foods per week have increased microbial diversity in the gut. Incorporate as many fruits, vegetables and legumes as possible to your meals. Do you get at least 30 different plant foods a week? If not, find a way to increase these foods in your diet. It will help your microbiome. Third, eat more polyphenols. Some of you may be asking, “what are polyphenols?” Polyphenols are nutrients in plants and plant-based foods that help your body manage inflammation and protect your body from oxidative stress. They can enhance your health in various ways, including cardioprotective and anticancer benefits. Polyphenols found in grapes and cranberries may increase A. muciniphila in the gut by creating an intestinal environment conducive for this beneficial bacteria to survive. So eat the rainbow in fruits, veggies and legumes! Next, make sure you are choosing heart-healthy fats. Levels of A. muciniphila are influenced by dietary intake of omega-3 fatty acids from fish oils. Omega-3’s lower levels of inflammation. Do you eat enough cod, salmon, or tuna in your diet? Next, consume prebiotics on a daily bases. Prebiotics are non-digestible food ingredients that feed the probiotics in your gut. Prebiotics are found in apples, asparagus, chia seeds, onions, and garlic. Studies have found that the appetite affecting hormones, like ghrelin, are modulated by prebiotics and the consumption of prebiotic fibers are associated with increased satiety after eating. The last strategy to encourage beneficial gut microbes is to include probiotics in your diet. Probiotics are microbes that provide health benefits for their host. They can be found naturally in food, or in a dietary supplement. Probiotic rich foods include fermented, vegetables, such as kimchi, yogurt, or kefir, with live active cultures and fermented soy bean, like tempeh or tofu. Probiotics minimize the amount of weight gain. Please consider everyone is unique and might handle prebiotics and probiotics differently. Not everyone can tolerate pre- and/or probiotic foods equally, making it important to add them to the diet gradually. Also, if you are immunocompromised, or have a GI condition, such as IBS, IBD, or SIBO, discuss these foods with your doctor first.

We briefly discussed being mindful with antibiotics. No matter when antibiotics are used in life, they can disrupt the gut microbiome, leading to loss of beneficial bacteria. This can affect weight, body fat percentage, short-chain fatty acid production, and metabolism of fatty acids. I realize that antibiotics are an important treatment and may be necessary on occasion, but overuse can cause significant health implications. If you need a course of antibiotics, don't be afraid to ask your doctor whether the addition of probiotics via food or supplements will be helpful for you to replenish the microbes in the gut. Reflect on your own history of antibiotic use and how it may be impacting your gut microbiome today.

Sometimes we wonder why we can’t loss weight. No matter what you eat, how little you eat or how much you exercise, the weight just doesn’t want to come off. Maybe it’s time to look at different avenues. Maybe it’s time to look at your gut health and work on how you can heal it in order to optimize your health. Consider all the strategies I have given you to encourage beneficial gut microbes and watch the shift in your weight along with healing the gut. You will feel so much better! I know I do! It is truly amazing how ultra-processed foods can make us feel so lethargic, bloated and overall unwell. When you stick to eating clean, eating whole foods, and as close to its natural form, you will feel energized and so much lighter. After reading this, do you believe there is a link between gut health and weight loss? See for yourself; try it!