Why being skinny doesn’t always mean you’re healthy: ‘Skinny fat’, dirty bulking and ‘big-boned’ explained

We’ve always associated health with looking a certain way – thin. It’s an easy link to make when we’ve been told that obesity is a major risk factor for over 200 metabolically linked diseases such as Type 2 diabetes, cardiovascular diseases, stroke, hypertension, fatty liver disease and certain cancers. 

But optimal health can – and does – exist in a wide spectrum of body shapes and sizes. From the powerful physiques of weightlifters to the lean figures of yoga practitioners, health is not only for those with a Victoria’s Secret model’s proportions. In fact, being slender doesn’t necessarily mean you’ve aced your health report card. (More on that in a while.)

A key indicator of good health is not the size you wear but what your health report says for markers like cholesterol, blood pressure and blood sugar levels. Even doctors would prescribe embracing body positivity, that is, accepting all body types, regardless of size and shape. 

“Body positivity only becomes problematic when it justifies declining health,” said Dr Lim Wee Peng, Parkway Shenton’s medical director. “Reconsider body positivity when excess weight limits your mobility, causes pain or leads to abnormal blood tests. Ultimately, it’s about adding years to your life and life to your years.” 

That means not using body positivity to disregard excess weight that contributes to conditions such as Type 2 diabetes. Or conversely, deliberately gaining mass to suit your fitness goals. Here’s a look at how certain actions to change or maintain your physique can affect your health. 

SKINNY FAT

Friends and colleagues envy how easily you can slip into size S clothes. On top of that, your weighing machine and calculated body mass index are looking good, too. But at your last health check, your doctor warned you about your high risk for diabetes, stroke and cardiovascular disease. Just what is going on? 

You may be “skinny fat” or what’s medically known as normal weight obesity (NWO). It is characterised by having a high body fat percentage (despite having a normal BMI), low muscle mass and ‘weak’ bones.

“NWO is dangerous because visceral fat (that is, fat stored around internal organs) triggers chronic inflammation and insulin resistance,” said Dr Yee Szemen, who heads Ng Teng Fong General Hospital’s Division of Endocrinology. 

“These individuals are unknowingly exposed to Type 2 diabetes, cardiovascular disease, hypertension, dyslipidaemia (an abnormal level of cholesterol or fat in the blood), and metabolic dysfunction-associated steatotic liver disease (liver fat accumulation, formerly known as non-alcoholic fatty liver disease).”

NWO is worryingly common in Singapore because up to 82 per cent of normal-weight individuals have it, according to Dr Yee. “It is the highest amongst Southeast Asian countries. This means the majority of seemingly normal-weight patients may actually have NWO,” he said, citing this study.

You may have NWO if you lead a sedentary lifestyle, which according to Dr Lim, is one of the biggest factors. Next is restricting calories without exercise, which then leads to muscle loss and fat gain. 

A diet high in refined carbs and low in protein is another culprit. “For example, a meal like fish soup with rice can be healthy but if the protein is insufficient and rice portions are large, it may not support muscle maintenance,” said Dr Lim.

Being female can just as well predispose you to NWO as it means that hormonal changes, especially with age-related sarcopenia, can affect body composition and tip it towards fat storage and muscle loss. And sometimes, it’s just your genetic luck of the draw. “Some individuals are predisposed to store fat viscerally even if they don’t look overweight,” said Dr Lim. 

The insidious part about NWO is that you can’t tell by appearance. “I often see patients who appear slim but show metabolic abnormalities during routine health screenings,” said Dr Lim. “Many are surprised because they look healthy on the outside, but their blood tests reveal otherwise.”

The way to diagnose it is through Dual-Energy X-ray Absorptiometry (DEXA) scans, said Dr Yee. “They are the gold standard for measuring body fat. In the clinic, waist circumference, waist-to-hip ratio and fasting lipid/glucose blood tests are also good indicators.” Digital scales using bioelectrical impedance analysis, he added, also provide a reasonable estimate but can be inaccurate. 

DIRTY BULKING

We associate gym-goers with regular exercise, high-protein foods and sleeping well – all the good stuff that go into growing quality muscles and strength. But for some individuals, who want shortcuts to getting big fast, they’ve resorted to training – and eating just about anything and everything.

It is a concept known as dirty bulking. “You’re not considering the quality or nutritional density of a food but rather, just laser-focused on overconsuming calories,” explained sports medicine physician Dr Michael Dakkak of Cleveland Clinic. “There’s no consideration for macronutrients. It’s just eating at will whatever your heart desires – and then some.” 

Some athletes bulk up during their off season and use the excess fat, in theory, to fuel their workouts when training begins, explained Dr Dakkak. 

But in doing so, it “results in simultaneous, high visceral and subcutaneous fat gain”, said Dr Yee. “Their body fat can easily exceed 20 per cent to 25 per cent, categorising them as overweight or obese by body fat percentage, despite their high muscle mass. As a result, they may potentially be exposed to medical conditions mentioned earlier if their visceral fat is high.”

Dr Lim added that “even with muscles, excess fat around the organs increases risks of high blood pressure, cholesterol imbalance and heart strain”. “Muscular imbalances can also cause poor posture and chronic shoulder or back pain.”

Another reason not to dirty bulk: A study of 600 elite athletes who did that showed no difference in muscle mass. Instead, the group that ate its way to bigger mass gained fat – plus, they didn’t improve their weightlifting ability. 

BEING “BIG BONED”

Back before body positivity was a thing, Cartman from the animated series South Park was already doing what Lizzo does for the self-love movement. (Remember his vehement refrain, “I’m not fat, I’m big boned!”?) 

So, can you really be big boned instead of fat, like Cartman insisted? One can indeed be big boned, said Dr Lim. “Frame size is real and largely genetic. A large-framed male might have an elbow breadth over 7.1cm and a female over 6.5cm." 

To measure your elbow breadth, raise your right arm until it is horizontal. Then, bend your elbow to form a 90-degree angle with your fingers pointing up. Use your left thumb and index finger to locate the two bony protrusions on either side of your right elbow. Place calipers to measure the two bony points at your elbow (see image below), or use your thumb and finger to gauge the gap, then measure that distance on a ruler.

However, having a higher bone mass doesn’t contribute to your heavier overall weight much. “Bone mass accounts for only about 15 per cent of your total body weight,” said Dr Yee. “A larger skeletal frame only adds roughly 1kg to 2.5kg of total body weight.” If you’re 15kg to 20kg over your healthy weight, it is due to adipose tissue or muscle, not bone, he added. 

Being genuinely large-framed does not expose you to metabolic diseases, said Dr Yee. “In fact, individuals with larger, denser bones typically have a higher peak bone mineral density, making them less prone to osteoporosis.”

Do big-boned individuals require more calcium to maintain their physique? “They don’t need more calcium than the average person – about 800mg to 1,000mg daily is sufficient,” said Dr Lim. “What matters is maintaining bone strength through weight-bearing exercise like jogging, stair climbing and resistance training.”