Unfortunately, stress levels, lack of sleep, and certain foods can negatively impact the gut microbiome, and lead to adverse health outcomes that may also affect the number on the scale. But before we discuss the gut microbiome’s role in weight management, let’s start off by defining what it is and how it impacts overall health.
What is the gut microbiome?
The gut microbiome refers to all the microbes in your intestines, and consists of 40 trillion bacterial cells and 1,000 different species of bacteria [1
The majority of these microbes are symbiotic (where both your body and microbiota benefit), but some are pathogenic (disease-promoting). While your body needs both to coexist and keep you healthy, a disturbance in this balance–otherwise known as dysbiosis–can make you more susceptible to chronic disease, inflammation, and even weight gain.
To help maintain a healthy gut balance, studies suggest that taking probiotics (either through food or supplements) can be beneficial, as these living microorganisms may restore the composition of the gut microbiome and prevent gut inflammation [30
How does gut microbiome affect health?
Notable research shows that diet and lifestyle choices both play a role in microbial function, so here’s how a balanced gut microbiome can positively affect your health [3
Some gut microbes (like those in the Lactobacillus
genera) have been shown to improve HDL (“good”) cholesterol
–both of which are associated with a lower risk of chronic disease and obesity [4
]. Moreover, a growing body of research indicates that dysbiosis is linked to a higher risk of heart failure, atherosclerosis, heart attack and stroke and taking probiotics may help lower cholesterol and the risk of heart disease [5
Improved immune function.
Gut microbiota help regulate immune homeostasis by communicating with immune cells, maintaining intestinal barrier integrity, preventing the growth of pathogenic organisms, and generating anti-inflammatory short chain fatty acids [7
Better brain health.
Studies have shown that certain species of bacteria in the gut help produce some neurotransmitters (such as serotonin) which influence brain functions such as mood [8
]. Gut microbiota also communicate with the central nervous system to influence brain function and behavior [9
]. While dysbiosis has been linked to anxiety and depression, probiotics can help restore balance and play a role in the treatment and prevention of these illnesses [10
Improved gut health.
Certain bacteria (such as Bifidobacteria
) have been shown to improve gut health, reduce bloating and ease abdominal pain, and alleviate diarrhea [13
]. Although the mechanisms of actions are still being explored, probiotics are thought to improve digestive health by helping seal the gaps between intestinal cells and preventing disease-causing bacteria from sticking to the intestinal wall [13
Research shows that inflammatory conditions (such as Crohn's disease, ulcerative colitis, multiple sclerosis, and rheumatoid arthritis) are influenced by microbial alterations in the gut and some strains of probiotics may improve symptoms [15
Correlation between obesity and gut microbiome
A gathering body of research shows that obesity and gut microbiome are closely related, so here are some ways that dysbiosis can impact the number on the scale [17
Studies have found that the gut microbiota in obese people is less diverse than that of lean people, which can reduce metabolic energy consumption and lead to sub-optimal glycemic control [19
]. Since the microbiome is involved in lipid and carbohydrate metabolism, energy homeostasis, and fat storage in the liver, dysbiosis can lead to insulin resistance, impaired glucose tolerance, and excess fat accumulation, all of which may contribute to obesity and type 2 diabetes [11
Studies show that the gut microbiota impacts leptin and ghrelin, two hormones that regulate hunger [23
]. As such, dysbiosis may lead to increased calorie intake, weight gain and obesity. Conversely, emerging evidence suggests that increasing the gut microbiota diversity through probiotic and prebiotic supplementation may dampen cravings [24
How to improve gut health for weight loss
Studies continue to show that dysbiosis can contribute to weight gain, so here are some ways to manipulate the gut microbiota to facilitate weight loss [26
Limit artificial sweeteners and refined sugars.
Artificial sweeteners and refined sugars can increase glucose levels and prompt the growth of unhealthy gut bacteria, which may lead to dysbiosis.
Some evidence has shown that artificial sweeteners–like aspartame–increase blood sugar by stimulating the growth of unhealthy bacteria (such as Enterobacteriaceae
)in the gut microbiome [28
]. Additionally, research suggests that refined sugar can increase inflammation and contribute to dysbiosis since it elevates Proteobacteria
(a harmful bacteria) in the gut and simultaneously decreases the abundance of Bacteroidetes
Added sugar intake also provides empty, non-satiating calories and disrupts leptin production, which can increase your desire for food and lead to weight gain [31
Take a probiotic supplement.
Probiotics are live microorganisms found in certain foods or supplements that confer a health benefit. Several strains of probiotics in the Lactobacillus
family have been shown to reduce weight and belly fat [33
]. Other notable research found that participants who took probiotic supplements experienced a significant reduction in BMI, fat mass, and waist circumference compared to those who didn’t take them [32
Try a plant-based diet.
Whether it’s vegetarian, vegan, or flexitarian, plant-based diets have been associated with numerous health benefits, some of which include weight loss and sustainable weight management [34
]. While you don’t need to completely swear off meat to see benefits, research suggests that those who eat more plants have better heart health, improved longevity, reduced risk of chronic disease, and a lower BMI. Additionally, plant-based diets are often rich in fiber–which promotes satiety, microbial diversity, and blood sugar control–and can be helpful for weight management.
According to one study, those who ate a vegan diet for 16 weeks saw a noticeable decrease in weight as well as an increase in the gut microbiome and overall health compared to those who didn’t go vegan [35
In addition to weight loss, studies show that those who eat plant-based diets have increased levels of Bifidobacterium
, both of which offer anti-inflammatory benefits and cardiovascular protection [35
Best foods for gut health
Whether you’re looking to improve your overall health or manage your weight, here are some science-based gut-friendly foods to include in your daily diet.
Eat a diverse range of foods.
Studies have found that eating a more diverse range of foods (such as plants, whole grains, and healthy fats) throughout the day can promote the growth of healthy microbes and create a healthy gastrointestinal microbiome [36
Focus on fiber.
High fiber foods (such as beans, berries, avocados, artichokes, oats, chia seeds, popcorn, and legumes) can promote the growth of Bifidobacteria
, a probiotic that has been shown to improve digestive health, break down food, absorb nutrients, and fight off disease-causing organisms[37
Enjoy more fermented foods.
Fermented foods (like yogurt, kimchi, sauerkraut, miso, kombucha, and kefir) contain healthy bacteria that can help reduce the amount of disease-causing species in the gut [38
Dive into prebiotics.
Prebiotics are food for good gut bacteria, inducing changes in the composition and/or activity of the microbiome [39
]. Apples, oats, garlic, asparagus, and bananas are just a few prebiotic foods that can encourage healthy bacteria growth and improve the microbiome.
Gut health has a large impact on overall health, as it’s intimately related to mental health, cardiovascular function, immunity, glycemic control, appetite regulation, and digestive health. Disturbing the balance of the gut microbiome–otherwise known as dysbiosis–can make you more susceptible to disease and even weight gain.
Multiple studies show that by manipulating the gut microbiota through probiotics, fermented foods, and a diverse diet, you can reduce inflammation, improve glycemic control, facilitate weight loss, or even prevent obesity [26
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