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Not all body fat is the same when it comes to health and weight loss. Fat that sits just under the skin, called subcutaneous fat, is mostly harmless and can even have some benefits. But deep belly fat, known as visceral fat, is more dangerous.
This fat wraps around important organs like the liver, pancreas, and intestines, increasing the risk of heart disease, diabetes, and inflammation.
Visceral fat is different because it is more active in the body’s metabolism. It releases substances that can make the body less responsive to insulin, leading to higher blood sugar levels and a greater risk of diseases.
It also increases inflammation, which plays a role in many chronic health problems. In contrast, subcutaneous fat is more of a storage reserve and doesn’t have the same harmful effects.
Researchers have found that two people with the same weight or Body Mass Index (BMI) can have very different amounts of visceral fat. Some people may have a large amount of visceral fat overall, while others may have a higher percentage of it compared to their total body fat.
This raises an important question: When trying to lose weight, is it more important to focus on reducing total visceral fat, or should we focus on lowering its proportion in the body?
A new study, published in BMC Medicine, explores this question. The research was led by Prof. Iris Shai from Ben-Gurion University in Israel, who also works with Harvard and Leipzig University. She explains that these findings challenge the common idea that weight loss is just about numbers on a scale.
“For doctors and dietitians, this study provides a new way to measure weight loss success,” Prof. Shai said. “Instead of just looking at how much weight a person loses, we need to consider what kind of fat they are losing and how it affects their health.”
Hadar Klein, a registered dietitian and one of the study’s lead authors, adds that BMI alone does not tell the full story. “Two people with the same BMI can have very different health risks depending on how much visceral fat they carry,” she said.
Dr. Hila Zelicha, another lead researcher, highlights the importance of personalizing weight loss strategies. “People with a high percentage of visceral fat may need different diet and exercise plans compared to those with a large amount of overall visceral fat,” she explained.
For years, BMI and overall weight loss have been the main ways to measure health progress. But this study suggests it’s time to move beyond the scale. Instead, a more personalized approach—based on where fat is stored in the body—could lead to better health outcomes.
The research analyzed data from 572 people who took part in two separate weight-loss trials over 18 months. These were some of the largest studies ever conducted using MRI scans to track changes in visceral fat. The participants followed different diet plans, and researchers measured both their total visceral fat and its proportion compared to their overall body fat.
Key Findings: How Visceral Fat Affects Health
Before weight loss, researchers found that people with a higher proportion of visceral fat (compared to total body fat) were more likely to have high triglyceride levels, which increase the risk of heart disease. Meanwhile, people with a larger total amount of visceral fat had higher inflammation levels and poorer blood sugar control, increasing their risk of diabetes.
During weight loss, participants lost an average of 22.5% of their visceral fat. Both total and proportional reductions in visceral fat led to better heart and metabolic health. However, losing total visceral fat had a stronger effect on improving insulin resistance and lowering levels of leptin, a hormone linked to obesity and diabetes.
To determine whether losing a larger amount of visceral fat or reducing its proportion was more important, researchers ran several statistical tests. They adjusted for factors like age, gender, and starting weight.
The study was a collaboration between researchers from Israel, the U.S., and Germany, involving institutions such as Harvard, Leipzig University, and Tulane.
What This Means for Weight Loss
This study provides new insights into how fat loss affects health. It suggests that not all weight loss is equal—reducing deep belly fat is more important than just lowering BMI. Personalized approaches, such as precision medicine, could help tailor diet and exercise plans based on how much visceral fat a person has.
People with a high percentage of visceral fat, even if they have a low BMI, could still be at risk for serious health conditions. Identifying these individuals and adjusting their weight loss strategies could help prevent diabetes, heart disease, and other metabolic disorders.
Future research will focus on better tools for measuring and managing visceral fat. Instead of relying only on weight and BMI, doctors may soon use more advanced methods to determine a person’s real health risks. This shift could lead to better and more effective treatments for obesity and metabolic diseases.
If you care about weight, please read studies about diet that can treat fatty liver disease, obesity, and hop extract could reduce belly fat in overweight people.
For more information about weight, please see recent studies about how to curb your cravings for ready-to-eat foods, and results showing what you can eat to speed your metabolism up.
The research findings can be found in BMC Medicine.
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