Why is fat loss more important than weight loss in obesity?
Guest writer: Rob van Berkel, Research dietitian and writer on nutrition and health
Why is fat loss more important than weight loss in obesity?
Many people with obesity focus on lowering their body weight when they want to lose weight. But it is actually fat mass that they want to lose. Fat loss provides greater health benefits than weight loss alone, because it targets the reduction of the harmful effects of excess body fat, especially around the abdominal organs. In addition to monitoring body weight, it is therefore also advisable to look at fat loss.
What does weight loss mean?
When someone is overweight (or considers themselves overweight), this is usually indicated using body weight or the Body Mass Index (BMI). BMI is body weight divided by height squared. In both cases, body weight is therefore central. The advantage is that it is easy to measure and calculate (Wu et al., 2024). Clients therefore often have a target weight in mind or want to get below a certain BMI. This can be achieved in different ways, but the client does not so much want weight loss as fat loss. An overly strict energy-restricted diet without sufficient protein and physical activity will indeed lead to weight loss, but probably not to the desired result. Muscle mass and possibly bone mass will also be lost, and the risk of weight gain (yo-yo effect) will increase.
Another point to take into account is that body weight can vary from day to day by as much as 1 kg. This is not fat or muscle mass. These fluctuations may be related to natural changes in fluid balance, fluid retention (salt and glycogen retain water), stomach and intestinal contents, sports activities, and hormonal factors.
What does fat loss mean?
The definition of obesity according to the World Health Organization (WHO) is “An abnormal or excessive fat accumulation that presents a risk to health” (WHO, 2025). Here, body weight is set aside and fat mass is central. And not without reason. Both the health and aesthetic consequences of obesity are caused by excessive fat accumulation. A higher muscle mass, which is also weight, has beneficial effects in this regard (Wang et al., 2023; Oliver et al., 2025).
When it comes to fat mass, it is important where it is located. In particular, fat in the abdominal cavity has a major impact on health because it is metabolically active, activates various harmful processes, and lies close to the abdominal organs. Thus, visceral obesity is associated with an increased risk of insulin resistance, type 2 diabetes, and cardiovascular disease (Dhokte et al., 2024; Lee ta;., 2024; Shen et a;l. 2024).
Why is visceral fat unhealthy?
Several mechanisms are known that explain why visceral fat accumulation is unhealthy (Minihane et al., 2015; Gkrinia et al., 2025):
When the fat cell is “full”, it releases free fatty acids into the portal circulation, increasing glucose production in the liver and decreasing insulin sensitivity. When the fat cell is “full”, metabolic and mechanical “fat cell stress” arises, leading to a local oxygen deficiency (hypoxia) and infiltration of macrophages (a type of immune cell) that produce a range of pro-inflammatory cytokines such as TNF-α, IL-6, and MCP-1. This leads to chronic low-grade inflammation, which plays a role in various health problems. Visceral fat accumulation causes dyslipidemia. The fatty acids that are released stimulate the liver to produce more triglycerides and VLDL, while HDL cholesterol often decreases. This worsens the risk of cardiometabolic diseases.
Many studies show that loss of visceral fat is accompanied by improvement of cardiometabolic risk factors (Ross et al., 2000; Gallagher et al., 2014; He et al., 2022; Abdullah et al., 2025), although not all (Sanguankeo et al., 2017).
How do you lose visceral fat?
When fat loss occurs, part of it will consist of visceral fat. But what is most effective for getting rid of visceral fat? An energy-restricted diet or physical activity?
A meta-analysis found that physical activity is more effective in reducing visceral fat mass, and that greater effort leads to a greater reduction in visceral fat (Recchia et al., 2023). Energy-restricted nutrition also worked well, but the evidence for a clear linear relationship between the size of the energy deficit and the amount of visceral fat lost is less strong. This is in line with what an earlier meta-analysis showed (Verheggen et al., 2016). Without weight loss, physical activity reduced visceral fat mass by 6.1%, while an energy-restricted diet hardly led to a reduction.
As a form of exercise, the choice is broadly between cardio and strength training. Although strength training is good for many things, cardio appears to be more effective when it comes to loss of visceral fat (Ismail et al., 2012; Vissers et al., 2013).
Conclusion
It is now clear that it is not so much total body weight, but rather the amount and location of fat mass that determine health. Visceral fat accumulation, and thus not necessarily subcutaneous fat, poses an increased risk for the development of cardiometabolic diseases such as insulin resistance, type 2 diabetes, and cardiovascular disease. Working specifically on the loss of (visceral) fat, for example through lifestyle interventions, is important for promoting overall health
Reference
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