Yes. Gut bacteria influence the chronic low-grade inflammation that ends in insulin resistance, fat deposits and weight gain. Both obesity and type 2 diabetes show dysbiosis. That means the gut microbiota (the bacteria in your gut) is out of balance and has fewer kinds of microbes.
Obesity and the disease associated with it, type 2 diabetes mellitus, have reached epidemic levels worldwide. So finding good ways to prevent and treat them is a global public health interest. A large body of evidence now suggests that the microbes in the human gut play a central role in how the body works and uses fuel. These microbes are called the gut microbiota. How gut bacteria steer key body jobs, such as glucose control and insulin resistance, is an important health issue. Here is how prebiotic/probiotic treatments affect these bacteria. They are now seen as promising ways to treat obese and diabetic patients.
1. The gut microbiota of an obese person…
Obesity is a chronic, complex disease with many causes. It is the fifth leading cause of death in the world. It accounts for almost 3.4 million deaths each year. Low-grade inflammation is the hallmark of metabolic disorders such as obesity, type 2 diabetes and nonalcoholic fatty liver disease. The microbiota is now seen as a real working “organ” because of its huge impact on human health. It has been the subject of intense research in recent years. The vast majority of microbes live in the gut. There they shape how the body works. They play basic roles in digestion, nutrition, immune control, and metabolism. Which microbes live there, and how active they are, can shift over time. It depends on many factors, including genes, sex, age, health, and drug/antibiotic use. Over the last decade, a large number of papers have reported a major role of microbiota in metabolic diseases. Notably, the evidence suggests an association between an out-of-balance gut and obesity. It also ties the gut to poor blood sugar control. And so it ties the gut to how T2DM starts.
2. Obesity, Diabetes, and Dysbiosis
A normal, healthy gut plays a key role in staying healthy. Dysbiosis means changes in both the makeup and the work of the gut bacteria. It is common in several diseases. These include metabolic diseases such as obesity and T2DM. A number of preclinical and clinical studies have compared gut bacteria in obese and lean people. They report that obesity is related to fewer kinds of microbes and greater depletion. In early obesity, studies report that weight gain is associated with a shift in gut bacteria. T2DM is generally seen as a feature of obesity. Even so, some studies have correlated poor blood sugar control and insulin resistance with a certain gut mix. Also, the diabetes drugs liraglutide and metformin have recently been shown to significantly lower body weight. They also improve how the body uses glucose. At the same time, they clearly change the gut mix. Liraglutide cut the gut patterns tied to obesity. It raised the patterns tied to being lean. Metformin changes the gut mix by making several bacteria grow. There is proof that gut bacteria play a part in how these diabetes drugs lower glucose. The gut is also a promising target to treat T2DM and poor blood sugar control.
3. How can Gut Microbiota be moderated?
Gut bacteria influence the chronic low-grade inflammation in several ways. That inflammation ends in insulin resistance, more fat deposits and weight gain, the marks of obese people. We now know these ways that obesity and inflammation start. So several plans to block or weaken them are being built and tested. The goal is to help obese and type 2 diabetic patients. We will look at these mechanisms and their effects: 3.1. Antibiotic Therapy Broad spectrum antibiotics greatly change the gut bacteria. Still, which bacteria survive and what that does for the host have not been determined. This is because the idea of a “healthy” gut microbiota is still under study. The main mechanism suggested for antibiotics is a drop in LPS (a bacterial toxin) in the blood. That lowers inflammation. It also improves the insulin resistance that obesity causes in the liver, muscle, and fat tissue. Better gut function has also been noted as a benefit of antibiotics. The metabolic gain in these tests is striking. Even so, using this approach in humans seems not to be the best option. There are hard problems, such as antibiotic resistance with long-term use. There is also evidence that indicates a link between long-term low-dose antibiotic use and weight gain. 3.2. Probiotics Probiotics are live microorganisms. You can get them from fermented foods or supplements. More and more studies show that the balance or imbalance of bacteria in your gut is linked to overall health and disease. Probiotics promote a healthy balance of gut bacteria. They have been linked to a wide range of health benefits. Obesity is a key cause of diabetes. So probiotics can help with weight loss in a number of ways. Here is an example. Some probiotics block the uptake of dietary fat in the gut. The fat then leaves the body in stool rather than being stored. Probiotics may also help you feel fuller for longer, burn more calories and store less fat. This is partly caused by raising levels of certain hormones, such as GLP-1. Probiotics may also help with weight loss directly. In one study, dieting women took Lactobacillus rhamnosus for 3 months. They lost 50% more weight than women who didn’t take a probiotic. Another study of 210 people found that taking even low doses of Lactobacillus gasseri for 12 weeks resulted in an 8.5%. But not all probiotics help with weight loss. Some studies have found certain probiotics, such as Lactobacillus acidophilus, can even lead to weight gain. 3.3. Prebiotics Prebiotics are food parts you cannot digest. Probiotics can feed on them. They work in the gut to increase populations of healthy bacteria. They also help digestion and help the gut make useful vitamins. Galactooligosaccharides (GOS) are the most advanced form of prebiotics. They are special fibers that feed good gut bacteria and help them grow. The major source of prebiotics is dietary fiber. They occur naturally in fruits and vegetables, but you can also take them as supplements. 3.4. Bariatric Surgery Bariatric surgery is an important way to treat obesity. It works quite well to achieve and protect weight loss. This success after bariatric surgery is not only about eating less food. The changed gut bacteria after bariatric surgery affect how well it works. Several things after surgery change the gut bacteria. The gut absorbs less food (malabsorption). Bile acids are handled in a new way. Stomach acid (pH) changes. Hormones change. The new gut bacteria also affect the body’s energy balance. Because of these reasons, weight loss is achieved after bariatric surgery.
4. What role will gut microbiota play in the treatment of T2DM in the future?
It is more and more clear that gut bacteria have a deep impact on health and well-being. Notably, it is now well-established that an out-of-balance gut is linked to poor blood sugar control and to T2DM. The exact role of gut bacteria is still not fully known. Even so, more study is likely to help a lot in treating obesity. It is also likely to help control the type 2 diabetes that follows. Current treatments of this complex chronic disease are far from ideal. This is because in a majority of patients, T2DM stays poorly controlled over the long run. Using pre/probiotics to control blood glucose has been considered for a long time. Finding the key roles of gut bacteria in T2DM has boosted research in this field. Better knowing how gut bacteria affect health will help shape new treatment plans. These plans will help find probiotic strains that fight diabetes. They will also help find diet changes that can increase helpful bacteria in the gut.
References:
1. Hindawi (2013): Influence of Gut Microbiota on Subclinical Inflammation and Insulin Resistance. Retrieved from https://www.hindawi.com/journals/mi/2013/986734/2. Frontiers in Endocrinology (2019): Impact of Gut Microbiota on Host Glycemic Control. Retrieved from https://www.frontiersin.org/articles/10.3389/fendo.2019.00029/full 3. NCBI (2019): The effects of bariatric surgery on gut microbiota in patients with obesity: a review of the literature. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6343052/ 4. Bimuno(2018) : Prebiotics. Retrieved from https://www.bimuno.com/prebiotics 5. Healthline (2016): 8 Health Benefits of Probiotics. Retrieved from https://www.healthline.com/nutrition/8-health-benefits-of-probiotics
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Medically reviewed by Dr. Gurpreet Singh Padda, MD, MBA, MHP
Interventional pain physician, addiction medicine specialist and obesity medicine diplomate.
Licensed in Missouri and Illinois.
Last reviewed June 18, 2026
