The human gut is home to literally trillions of microorganisms. These organisms include bacteria, fungi, parasites, and viruses. This may sound like a problem, but the majority of these organisms are there to help, not hurt your body. The environment these organisms live in is called the microbiome. The microbiome helps promote good health and may reduce weight gain. 

The gut microbiome is one of the most complex systems in the human body. Scientists say it plays a key role in helping you digest food and turn it into energy. One study also shows that there may be a connection between a healthy gut microbiome and weight loss.

What Is the Gut Microbiome?

The gut microbiome is the term for the complex ecosystem of bacteria, viruses, protozoa, and fungi in the gastrointestinal tract. 

Each person’s intestinal microbiome is unique, with a personalized balance of microorganisms. These invisible organisms help with nutrient absorption and the production of enzymes, vitamins, amino acids, and short-chain fatty acids (SCFAs).

A balanced microbiome with a diverse population of organisms plays an important role in processing the food you eat and turning it into energy. If your microbiome becomes unbalanced, it might increase health issues such as inflammation, metabolic disorders, and weight gain. 

4 Ways Gut Microbiota Might Influence Your Response to Weight Loss

Scientists are still investigating the relationships between gut microbiota and weight loss. There are many unanswered questions about how the microbiome affects weight. But some research so far shows that gut microorganisms might help boost metabolism, decrease hunger, and reduce fat accumulation. 

1. Microbiota diversity influences the energy you get from food

Research shows it’s beneficial to have a diverse and balanced population of microorganisms in the gut. A diverse microbiome helps extract energy from food, defend against harmful pathogens, and influence inflammatory responses.

A balanced gut requires many different types of microorganisms that can perform all the necessary functions for digestion and energy conversion. This diversity ensures there is always a population of microbes available to break down food and convert it to energy. 

Research suggests that the best foods for the microbiome are actually diverse foods. Eating many different foods can help support microbial diversity and balance the gut microbiome. Different microbes like different foods and flourish when their favorite meals are available. 

Varying your diet and including plenty of fruits and veggies can be an excellent way to help reach your gut health and weight loss goals. 

Fun Fact: When you track what you eat with MyFitnessPal, you receive a weekly report snapshot that summarizes how many fruits, vegetables, protein-rich foods, and sweets and snacks you ate. Learn more

2. Intestinal bacteria can regulate appetite hormones

The gut microbiome can impact hormones that affect appetite. A comprehensive literature review published in 2021 looked at the relationship between the gut microbiome and appetite hormone levels. The authors—who conducted the experiments on rodents—found that a well-populated gut with diverse microorganisms is associated with leptin signaling. Leptin is a hormone that tells your body you’ve had enough food.  

The same article suggested that there’s a complex relationship between microbiota and the hormone ghrelin. Ghrelin triggers feelings of hunger. Some evidence suggests that taking prebiotics inhibits ghrelin signaling, which can reduce appetite. 

Finally, the article talked about the effects of microbiota on insulin. Insulin is a hormone that triggers feelings of fullness after eating. The authors noted that fewer types of gut bacteria are associated with higher insulin resistance, which can make people prone to overeating. So, a diverse microbiome may improve insulin sensitivity and make it easier to manage diabetes. Paired with physical activity, it could also help improve body composition and promote weight loss.

3. Gut bacteria help produce short-chain fatty acids

One of the things gut microbiota does is break down dietary fiber through a fermentation process. A 2019 article in the journal Advances in Nutrition reviewed how the fermentation process converts fiber into short-chain fatty acids (SCFAs). 

SCFAs are an important source of energy for the digestive tract. The fermentation and production of SCFAs may also contribute to: 

• Feeling full
• Mineral absorption
• Inflammation reduction
• Weight loss

One area of interest is the relationship between SCFAs and diabetes. A 2024 review of prior research concluded that higher SCFA concentrations—which means having more SCFAs in your gut—is linked to lower levels of fasting insulin. That may be good news for managing type 2 diabetes. 

An article from 2022 examined the relationship between SCFAs and weight reduction. Experts pointed to a correlation between gut microbiota functionality, SCFA production, and successful weight management, but the exact reason is still unclear. The authors noted that a diet with plenty of high-fiber foods may promote increased production of SCFAs and SCFA-producing bacteria to support weight management.

The good news is that while scientists work on determining exactly why high-fiber foods and SCFAs improve health, you can take advantage of their benefits. Research shows that you can increase the production of SCFAs by eating a healthy microbiome diet rich in high-fiber foods like fruits, vegetables, and whole grains. 

The nutrition tracking tools from MyFitnessPal provide an easy way to help you track and adjust your dietary choices. The app shows you the fiber content of the foods you eat, so you may decide to increase your fiber intake if needed to help boost your gut microbiome. Research shows that 95% of Americans aren’t eating as much fiber as they should be. Tracking is a great way to be sure you’re getting the right quantity of fiber. 

The app can also give you recipes and meal ideas to increase the variety of foods you eat and improve the diversity of your microbiome. Check out these and all the great features on the MyFitnessPal app.

4. Beneficial bacteria can regulate your fat storage

The gut microbiota isn’t just about digestion. It also plays a role in fat storage. A 2022 article describes a study done on rats that showed certain types of gut bacteria made the rats’ intestines absorb more glucose. More glucose in the intestine means more fat synthesis in the liver. On the flip side, some bacteria actually inhibit fat storage. 

This means the kind and diversity of bacteria living in your gut might influence your weight by inhibiting fat storage or triggering fat synthesis, but more research needs to be done on humans. Balancing your gut bacteria could be key to weight control.

The Bottom Line

The gut microbiome is a complex ecosystem that is unique to every person. Researchers have only begun to understand all the ways gut microbiota affect health and weight. 

What we do understand is that diet choices can have a positive impact on gut health. A balanced diet that includes a variety of foods rich in fiber is likely to provide the most benefit to your gut microbiome.