There’s no shortage of fat loss advice out there. Cut carbs. Do more cardio. Skip dinner. Sleep eight hours. Drink more water. Try fasting. The list goes on, and yet, for many people, the fat refuses to budge, especially the stubborn kind around the belly.
But what if your gut health is the hidden piece in this frustrating puzzle?
Over the last decade, science has uncovered something extraordinary: our gut microbiome, the trillions of bacteria living in our digestive tract, plays a major role in how we store fat, burn calories, and manage weight. The buzz around probiotics is no longer just about digestion, it’s about metabolism, inflammation, hormones, and, yes, fat reduction.
And not all probiotics are created equal. Some are uniquely built to support your body's ability to manage weight and reduce fat mass, especially when it comes to the difficult-to-lose abdominal fat. Two specific strains are now at the forefront of this research: Lactobacillus curvatus HY7601 and Lactobacillus plantarum KY1032.
Let’s break down what the latest science says about them, and how they can become part of your daily approach to sustainable fat reduction.
Fat Isn’t the Enemy, Imbalance Is
It’s easy to blame body fat for all health problems, but fat is a normal, necessary part of the human body. The issue arises when fat accumulates in harmful areas, especially visceral fat, the type that surrounds our organs and increases risk of metabolic diseases.
Several factors can cause this kind of fat gain:
- Hormonal imbalances (insulin resistance, leptin resistance)
- Chronic stress and cortisol
- Poor sleep quality
- Sedentary lifestyle
- Gut microbiome imbalance
The last one has taken centre stage in recent research. People with obesity have been found to have a different gut bacterial composition compared to lean individuals, including lower diversity and higher levels of certain fat-storing bacteria².
Balancing the gut microbiome, then, becomes a smart strategy for body composition, especially if that balance includes targeted probiotics.
The Probiotic Strains Making a Difference: HY7601 and KY1032
Among the many strains of probiotics studied, two have emerged as game-changers in the area of fat metabolism:
- Lactobacillus curvatus HY7601
- Lactobacillus plantarum KY1032
These strains have been extensively researched in high-quality, placebo-controlled human trials, not just mouse models.
In a 12-week randomized, double-blind, placebo-controlled clinical trial, participants who took these two strains daily experienced:
- A significant reduction in total body fat
- Decrease in visceral and subcutaneous fat
- Lower waist circumference and BMI
- Healthier shifts in gut microbiota composition¹
These changes were observed without extreme dietary or lifestyle changes, which makes the outcome even more compelling.
How These Strains Work Inside the Body
These two strains don't just sit in your gut passively. They’re highly active contributors to healthier metabolism:
- HY7601 helps reduce fat accumulation by modulating inflammatory responses and supporting healthy lipid metabolism. It encourages fat excretion through faeces and promotes fat oxidation.
- KY1032 supports gut microbial balance, encouraging a microbiome composition that resists fat storage. It has also been linked to improved bowel habits and a reduction in gut dysbiosis ².
Together, they form a synergistic duo: one focusing on active fat metabolism and inflammation reduction, the other supporting microbial balance and bowel regulation. This combination allows the body to process nutrients more effectively and burn fat more efficiently, especially around the abdomen.
Targeting the Real Threat: Visceral Fat
One of the most promising findings is that these probiotics help reduce visceral fat. This is the fat that wraps around your internal organs, and it’s closely linked to:
- Cardiovascular disease
- Insulin resistance
- Type 2 diabetes
- Fatty liver disease
By helping reduce this specific type of fat, HY7601 and KY1032 do more than support cosmetic weight loss, they support long-term metabolic health.
Improved Gut Health Supports Better Fat Metabolism
Fat loss and gut health are deeply connected. A healthier microbiome helps regulate:
- Appetite-controlling hormones like ghrelin and leptin
- Digestive efficiency and nutrient absorption
- Fat storage signals and metabolic responses
- Inflammation levels, which can drive fat gain
HY7601 and KY1032 are shown to support all these pathways. In one study, participants had not only reduced fat mass, but also improved microbial diversity, suggesting their gut environment became healthier overall².
Better gut health = more efficient body systems = better fat metabolism.
How Fast Will You See Results after taking HY7601 and KY1032 probiotic combination?
In clinical trials, participants saw noticeable results in as little as 8 to 12 weeks. That’s because probiotics work gradually, encouraging the gut to restore its own balance.
This timeline aligns with what Second Nature’s health researchers also observed, body weight often plateaus before adjusting to a new “set point.” Probiotic support can help navigate these plateaus and allow the body to reset toward a leaner equilibrium⁴.
You may not see a dramatic overnight drop on the scale, but subtle changes in waist size, energy levels, digestion, and even skin clarity are early signs your gut microbiome is transforming.
Probiotics as a Powerful Daily Partner
Probiotics are not just an add-on, they’re a daily ally in your fat reduction journey.
A few things to keep in mind:
- Strain specificity matters. Look for names like HY7601 and KY1032 on labels.
- More strains ≠ better. Multi-probiotics often include many strains in tiny amounts.
- Dosage matters. Look for products with adequate CFUs (colony forming units) backed by research.
While daily movement, hydration, sleep, and balanced eating all support long-term fat reduction, probiotics like HY7601 and KY1032 can give your body the internal push it needs, especially when external habits aren’t perfect.
Even people with moderate lifestyle changes saw improvement in body fat metrics during the 12-week trial¹, showing that gut support can be effective and empowering regardless of where you're starting from.
What Else Might You Notice?
Though fat reduction is the star of the show, users of HY7601 and KY1032 have reported a few unexpected benefits:
- More regular bowel movements
- Less bloating or indigestion
- Better tolerance for various foods
- A general feeling of lightness or improved digestion
These secondary benefits support fat loss indirectly by improving the efficiency of your digestive and metabolic systems.
Let Your Gut Work With You, Not Against You
Trying to lose fat without addressing your gut health is like trying to sail with your anchor down.
With growing research and promising human trials, Lactobacillus curvatus HY7601 and Lactobacillus plantarum KY1032 offer a new way to support fat reduction, from the inside out.
Rather than relying solely on willpower, harsh diets, or extreme routines. Consider this: your body wants balance. These specific probiotics help it get there naturally, by gently shifting your microbiome toward better fat-burning and less fat-storing modes.
Your gut isn't just a part of your health story, it's a central character. Nourish it wisely, and it will return the favour with energy, resilience, and yes, a leaner, healthier you.
References
1. Youn, S.Y., Song, E.J., Lee, J.Y., Kim, H.R., Park, J.W., Kim, K.T., & Jeong, D.Y. (2021). Supplementation with two probiotic strains, Lactobacillus curvatus HY7601 and Lactobacillus plantarum KY1032, reduces body fat in overweight and obese adults. Scientific Reports, 11, Article 16252. https://doi.org/10.1038/s41598-021-95402-6
2. Park, J.W., Jeong, D.Y., & Kim, K.T. (2022). Effects of Lactobacillus curvatus HY7601 and Lactobacillus plantarum KY1032 on Body Fat Reduction and Gut Microbiota: A Randomized, Double-Blind, Placebo-Controlled Study. Nutrients, 14(4), 799. https://doi.org/10.3390/nu14040799
3. PNF024-02-05. Clinical summary of probiotic strain efficacy in body fat regulation. Denps Denmark.
4. Second Nature. (2025). Weight-loss Plateaus Explained. Retrieved from https://www.secondnature.io
5. Johns Hopkins Medicine. (n.d.). Gut Health and Weight Loss. Retrieved from https://www.hopkinsmedicine.org
