The Anti-Obesity Effect of Lactobacillus gasseri Explained

November 25, 2025 •

4 min read

In a 12-week human study, participants consuming milk fermented with a specific strain of Lactobacillus gasseri saw an average reduction of 8.5% in their abdominal visceral fat area. This remarkable result highlights the significant potential of the anti-obesity effect of Lactobacillus gasseri by influencing fat absorption and reducing inflammation.

Quick Summary

Studies suggest that specific strains of the probiotic Lactobacillus gasseri can help reduce body weight and visceral fat accumulation through various mechanisms. These include inhibiting fat absorption, increasing fatty acid oxidation, modulating appetite hormones, and reducing inflammation associated with obesity.

Key Points

Visceral Fat Reduction: Specific strains of Lactobacillus gasseri have been clinically shown to significantly reduce abdominal visceral fat, which is strongly linked to metabolic diseases.
Inhibits Fat Absorption: Certain strains inhibit the intestinal absorption of dietary fat, leading to increased excretion of fat from the body.
Influences Hormonal Signals: Supplementation can decrease levels of the appetite-regulating hormone leptin, potentially improving sensitivity and signaling satiety.
Enhances Fat Metabolism: L. gasseri promotes the expression of genes involved in fatty acid oxidation, encouraging the body to burn fat for energy.
Reduces Inflammation: The probiotic helps combat the low-grade systemic inflammation associated with obesity by inhibiting pro-inflammatory gene expression.
Strain-Specific Effects: The anti-obesity benefits are highly dependent on the specific strain of L. gasseri used, with strains like BNR17 and SBT2055 being well-studied.
Improves Gut Diversity: By promoting a more diverse and balanced gut microbiota, L. gasseri supports overall metabolic health.
Requires Consistent Use: Clinical studies show that continuous consumption of L. gasseri is necessary to maintain its anti-obesity effects.

The Gut-Obesity Connection

For decades, obesity was viewed as a simple matter of energy imbalance. However, mounting evidence reveals a much more complex picture involving the gut microbiome. The community of microorganisms living in our digestive tract plays a critical role in metabolic function and energy regulation. An imbalanced gut flora, or dysbiosis, is often observed in overweight and obese individuals, with some studies noting a higher ratio of Firmicutes to Bacteroidetes bacteria compared to lean individuals. This imbalance can impact the body's ability to regulate energy, store fat, and manage inflammation, making the gut a prime target for new obesity treatments, including probiotics like Lactobacillus gasseri.

Key Mechanisms Behind Lactobacillus gasseri's Anti-Obesity Effect

The anti-obesity effects of Lactobacillus gasseri are not based on a single action but rather a multifaceted approach to metabolic regulation. Different strains, such as BNR17 and SBT2055, have been shown to work through various pathways to influence body fat accumulation.

Inhibiting Dietary Fat Absorption

One of the primary ways Lactobacillus gasseri helps manage weight is by limiting the amount of fat the body absorbs from food. Research indicates that certain strains can interfere with the breakdown and absorption of dietary fat in the small intestine, leading to an increased amount of fat being excreted in feces. This is thought to involve the production of certain enzymes or the modulation of genes involved in fat transport and binding within the intestinal cells.

Modulating Appetite and Fat Storage Hormones

Lactobacillus gasseri can influence the body's hormonal signals related to appetite and fat storage. Studies have shown that supplementation can reduce levels of the hormone leptin. Leptin, which is primarily produced by fat cells, signals satiety to the brain. In obesity, leptin resistance is common, meaning the brain doesn't receive the signal to stop eating. By helping to lower circulating leptin levels, L. gasseri may help improve sensitivity to this crucial appetite-regulating hormone. Additionally, some probiotics can increase levels of angiopoietin-like 4 (ANGPTL4), a protein that helps decrease fat storage.

Upregulating Fat Metabolism Genes

Another significant mechanism is the probiotic's effect on gene expression related to lipid metabolism. Research on specific strains like BNR17 has found that it can increase the expression of genes involved in fatty acid oxidation while reducing the expression of genes that promote fatty acid synthesis. This shift encourages the body to burn fat for energy more efficiently rather than storing it in adipose tissue. This action can lead to a decrease in overall body fat mass, even without a significant change in caloric intake.

Combating Low-Grade Inflammation

Obesity is often linked to a state of chronic, low-grade inflammation, particularly in visceral fat tissue, which can contribute to insulin resistance and other metabolic issues. Certain Lactobacillus gasseri strains possess anti-inflammatory properties, with studies showing they can inhibit the upregulation of pro-inflammatory genes in adipose tissue and help reduce inflammatory markers. By improving the inflammatory state, the probiotic helps create a healthier metabolic environment within the body.

Comparison of Lactobacillus gasseri Strains

Different strains of Lactobacillus gasseri have been investigated for their anti-obesity effects, with varying results. The effects are often highly specific to the individual strain used.


Feature	Lactobacillus gasseri BNR17	Lactobacillus gasseri SBT2055
Research Focus	Multiple human trials and animal studies.	Significant animal and human research demonstrating efficacy.
Key Outcome	Reduces visceral fat accumulation and waist circumference in obese adults.	Lowers abdominal adiposity and reduces overall fat mass.
Primary Mechanism	Elevated expression of fatty acid oxidation-related genes.	Inhibits dietary fat absorption in the intestine.
Inflammatory Effect	Reduces levels of leptin and insulin in serum.	Inhibits pro-inflammatory gene expression in visceral adipose tissue.
Diet Dependence	Showed effects even without strict calorie restriction in some studies, but benefits were enhanced with mild restriction.	Proven effective in fermented milk products consumed daily for 12 weeks.

The Role of Gut Microbiota Diversification

Beyond the specific mechanisms, Lactobacillus gasseri also contributes to a healthier, more diverse gut microbiota. An increased abundance of beneficial bacteria, such as Bacteroidetes, relative to Firmicutes, is often associated with a leaner phenotype. By promoting a balanced microbial community, L. gasseri supports overall gut health, which in turn benefits systemic metabolic functions and contributes to weight management. Some studies also show an increase in microbial diversity, particularly when using synbiotic formulations (combining probiotics with prebiotics) containing L. gasseri.

Conclusion: A Promising Probiotic for Weight Management

In summary, the anti-obesity effect of Lactobacillus gasseri is supported by a growing body of research demonstrating its ability to help manage weight and reduce visceral fat. This is achieved through a range of mechanisms, including reducing dietary fat absorption, modulating appetite and fat storage hormones, increasing fatty acid oxidation, and combating obesity-related inflammation. While these effects are strain-specific and dependent on consistent consumption, specific strains like BNR17 and SBT2055 have shown promising results in clinical trials. As part of a balanced diet and healthy lifestyle, supplementation with targeted L. gasseri strains offers a valuable complementary approach to combating obesity and improving metabolic health. Further research is ongoing to fully elucidate the long-term effects and optimal applications of these beneficial bacteria.

Practical Steps for Incorporating Lactobacillus gasseri

If considering Lactobacillus gasseri for weight management, it is best to choose a reputable brand with a specific strain proven effective in clinical trials. Be aware that the strain name (e.g., BNR17 or SBT2055) should be clearly listed on the product label. Consistent daily consumption is important to maintain the probiotic's effect, as benefits may wane if stopped. It's always advisable to consult a healthcare provider or a registered dietitian before starting any new supplement, especially for those with compromised immune systems or underlying health conditions.

Frequently Asked Questions

Strains like Lactobacillus gasseri BNR17 and SBT2055 have been the focus of numerous studies and have shown promising results in reducing body fat, particularly in the abdominal area.

It reduces abdominal fat by several mechanisms, including inhibiting the absorption of dietary fat, upregulating fat metabolism genes, and reducing inflammation in visceral adipose tissue.

While some fermented foods like certain yogurts and kefir may contain Lactobacillus gasseri, probiotic supplements are more likely to contain the specific, clinically tested strains in effective doses needed for weight management.

Studies have shown that the anti-obesity effects, such as reduced fat mass, may be attenuated after ceasing consumption, suggesting that continuous intake is necessary to maintain the benefits.

While generally considered safe for most healthy individuals, people with compromised immune systems should avoid probiotics. It is always best to consult a healthcare provider before starting any new supplement.

While some studies have shown beneficial effects even without strict calorie restriction, the anti-obesity effects are most pronounced when combined with a healthy diet and lifestyle. L. gasseri works best as a complementary aid.

Clinical trials often report results after consistent daily consumption over a period of 12 weeks or more. Individual results can vary based on genetics, diet, and baseline health.