Lifespan is how long you live. Healthspan is how many of those years you spend without chronic disease, without medication lists that need a spreadsheet, and without the fatigue, joint pain and breathlessness that quietly shrink what a body can do. The two numbers have drifted apart. Life expectancy in Singapore is among the highest in the world, but the years lost to disability from metabolic disease have grown alongside it. Body composition, not body weight alone, is one of the strongest levers we have over that gap.
This matters because two men who weigh the same and look similar in clothes can carry very different metabolic risk, and the difference usually comes down to where the fat is stored.
Visceral fat versus subcutaneous fat
Not all body fat behaves the same way. Subcutaneous fat sits just under the skin, the layer you can pinch on the arms, thighs and hips. It is metabolically fairly quiet. Visceral fat is different: it wraps around the liver, pancreas and intestines deep inside the abdominal cavity, and it behaves almost like an active organ.
Visceral fat releases free fatty acids directly into the portal vein leading to the liver, promotes low-grade inflammation through cytokines such as interleukin-6 and tumour necrosis factor-alpha, and disrupts the normal signalling of hormones including insulin, cortisol and testosterone. It is strongly associated with fatty liver disease, elevated triglycerides, hypertension and type 2 diabetes, largely independent of how much the person actually weighs.
This is why two men with an identical BMI can have very different risk profiles. A man with a broad frame and evenly distributed subcutaneous fat may carry excess weight with relatively low metabolic risk. A leaner-looking man with a protruding abdomen and thin limbs, sometimes described informally as "skinny fat", may carry a disproportionate visceral fat load and correspondingly higher risk of insulin resistance and cardiovascular disease, despite a BMI that looks unremarkable on paper.
Why Asian BMI cut-offs are different
Standard BMI categories were developed largely from data in Western populations, and they underestimate metabolic risk in Asian populations at any given BMI. For the same BMI, people of Asian ethnicity tend to carry a higher percentage of body fat and a greater proportion of that fat viscerally, compared with Caucasian populations. This observation led health authorities across Asia, including Singapore, to adopt lower BMI thresholds.
| BMI category | Standard (WHO general) | Asian cut-off |
|---|---|---|
| Underweight | Below 18.5 | Below 18.5 |
| Normal | 18.5-24.9 | 18.5-22.9 |
| Overweight | 25-29.9 | 23-27.4 |
| Obese | 30 and above | 27.5 and above |
Under Asian cut-offs, a BMI of 23 is already classified as overweight, and 27.5 as obese, several points lower than the thresholds many people are used to seeing quoted online. A man who checks an international BMI calculator and finds himself comfortably "normal" at a BMI of 24 may, under the classification actually recommended for his own population, already be in the overweight range with meaningfully elevated risk of insulin resistance and related conditions.
Waist circumference: the number BMI misses
Because BMI cannot distinguish muscle from fat or tell you where fat is stored, waist circumference is used alongside it as a more direct marker of visceral adiposity. In Asian men, a waist circumference of 90 cm or above is generally considered indicative of central obesity and raised metabolic risk, compared with 80 cm in women.
Waist circumference is simple to measure at home: a tape measure at the level of the navel, at the end of a normal exhale, without pulling the tape tight enough to compress the skin. Tracking this figure over months tells you more about visceral fat trends than the bathroom scale does, because a man who loses fat and gains muscle through resistance training may see very little change in total body weight while his waist circumference falls steadily.
Metabolic syndrome: when several risk factors cluster
Metabolic syndrome is not a single disease but a cluster of risk factors that, when they occur together, sharply raise the risk of cardiovascular disease and type 2 diabetes. It is typically diagnosed when three or more of the following are present:
- Waist circumference above the ethnicity-specific threshold (90 cm in Asian men)
- Blood pressure of 130/85 mmHg or higher, or on treatment for hypertension
- Fasting triglycerides of 1.7 mmol/L or higher
- HDL cholesterol below 1.0 mmol/L in men
- Fasting glucose of 5.6 mmol/L or higher, or diagnosed type 2 diabetes
Visceral fat is the common thread running through nearly all of these criteria. A man who reduces visceral fat through sustained weight loss will typically see improvement across several of these markers simultaneously, rather than needing five separate interventions, because they share a single upstream driver.
Insulin resistance: the mechanism behind the numbers
Insulin resistance develops when cells in the muscle, liver and fat tissue stop responding normally to insulin, forcing the pancreas to produce more of it to keep blood glucose within range. Visceral fat is a key driver of this process. Fatty acids released from visceral fat accumulate in the liver and muscle, interfering with the intracellular signalling pathways insulin normally relies on.
In the early stages, insulin resistance is silent. Fasting glucose can remain normal for years while insulin levels climb to compensate, a state sometimes picked up incidentally on a comprehensive health screening that includes fasting insulin alongside glucose. Left unaddressed, this progresses through prediabetes towards type 2 diabetes, and it also independently raises cardiovascular risk, contributes to fatty liver disease, and in men is linked to lower testosterone, since insulin resistance and excess visceral fat both promote the conversion of testosterone to oestrogen in fat tissue.
Weight loss, particularly loss of visceral fat, improves insulin sensitivity often before significant weight change is visible on the scale. Reductions in liver fat can occur within weeks of starting a calorie deficit, well ahead of substantial total weight loss, which is one reason blood markers sometimes improve faster than appearance does.
Muscle mass: the part of the equation people forget
Weight loss without attention to muscle preservation can be counterproductive for healthspan even when the number on the scale looks like success. A meaningful proportion of weight lost through calorie restriction alone, without resistance training or adequate protein, is lean muscle rather than fat. This lowers resting metabolic rate, makes long-term weight maintenance harder, and accelerates the natural age-related decline in muscle mass known as sarcopenia, which independently predicts frailty, falls and loss of independence in later life.
Muscle tissue is also metabolically valuable in its own right. It is the primary site of glucose disposal in the body, meaning more muscle mass improves insulin sensitivity directly, on top of any benefit from fat loss. This is why the two goals, losing visceral fat and preserving or building muscle, are not separate projects but reinforce each other.
Practical priorities for protecting muscle during weight loss include protein intake in the region of 1.6 grams per kilogram of body weight daily, resistance training at least twice weekly, and avoiding excessively aggressive calorie deficits that force the body to break down lean tissue for energy. This becomes particularly relevant for men using prescription treatments for weight loss, where reduced appetite can make it harder to reach protein targets without deliberate planning; our guide to prescription weight loss medication covers this in more detail.
From lifespan thinking to healthspan thinking
The shift in framing matters. A man focused purely on lifespan might ask whether a treatment or habit adds years. A man focused on healthspan asks a different question: will I still be able to walk up stairs without breathlessness, avoid a hip replacement, keep my testosterone in a healthy range, and stay off five separate medications, at 70?
Visceral fat reduction, monitored through waist circumference rather than weight alone, and paired with muscle preservation through resistance training, is one of the few interventions that moves the needle on nearly every marker relevant to that question at once: blood pressure, lipids, glucose control, liver fat, hormonal balance and physical function. This is a meaningfully different goal from simply seeing a lower number on the scale, and it is why a structured approach, ideally with baseline blood work and periodic review, tends to outperform an unstructured attempt to "lose weight" in isolation.
Tracking progress beyond the scale
For men serious about healthspan, a useful monthly routine is to record three numbers rather than one: body weight, waist circumference, and a simple measure of physical function such as how many push-ups can be completed in a set or how a familiar flight of stairs feels. Weight alone can plateau or fluctuate with hydration and glycogen stores even while visceral fat continues to fall and muscle continues to build, which is why relying on the scale in isolation often leads people to abandon a plan that is actually working. Periodic blood work, ideally every three to six months, closes the loop by confirming that the changes being felt and measured externally are matched by improvements in the markers that actually predict long-term disease risk.
Common questions
Is BMI still useful if it does not account for fat distribution?
BMI remains a useful screening tool because it is quick, reproducible and correlates reasonably well with risk at a population level. Its limitation is at the individual level, particularly in people with high muscle mass or a lean but centrally obese build. Waist circumference alongside BMI, using Asian-specific cut-offs, gives a more complete picture than BMI alone.
How quickly does visceral fat respond to weight loss compared with subcutaneous fat?
Visceral fat tends to respond relatively quickly to a sustained calorie deficit and increased physical activity, often faster than subcutaneous fat in the same person. This is one reason waist circumference and liver-related blood markers can improve within the first few weeks of a structured programme, even before significant total weight loss is visible.
Can someone with a "normal" BMI still have unhealthy visceral fat levels?
Yes. This pattern, sometimes called normal-weight obesity or "skinny fat", is relatively common and is a reason clinicians look beyond BMI to waist circumference, blood pressure and fasting blood markers when assessing metabolic risk, rather than relying on weight or appearance alone.
Does muscle loss during weight loss matter if the scale is still going down?
It matters considerably for long-term outcomes. Muscle loss lowers metabolic rate, making weight regain more likely, and accelerates age-related functional decline. Protein intake and resistance training during any weight loss effort are not optional extras, they are part of what determines whether the result is sustainable.
What is a reasonable first step if I am concerned about visceral fat?
A waist circumference measurement, blood pressure check and a fasting blood panel covering glucose, insulin, lipids and liver function give a clear starting picture. This can be arranged as part of a general health screening or a dedicated consultation focused on weight and metabolic health, both available at our clinic on Orchard Road.
For a structured, medically supervised approach to reducing visceral fat and preserving muscle mass, visit our weight loss programme page or book an appointment with one of our SMC-registered doctors.