We all have that slim friend who seems to be able to eat anything they want and not gain a gram. It can be frustrating- and seem highly unfair- to those of us who eat well and exercise regularly, yet somehow still struggle with getting those last few kilos off.
But your thin friend may not be as healthy as you think. It’s possible to appear slim and still contain unhealthy levels of body fat on the inside. Scientists have given this phenomenon a more technical name: normal-weight obesity. It’s a real health concern, with evidence growing that it may be just as harmful as being obese.
What is normal-weight obesity?
People with normal-weight obesity have a body mass index (BMI) that falls within the normal ‘healthy’ range. But they also have a high body fat percentage and lurking deep in their abdominals are layers of fat. Research has found that these people have a higher risk of developing conditions such as metabolic syndrome, high blood pressure, type 2 diabetes and heart disease than those with a healthy BMI.
Then there is ‘central obesity’. That’s when excess body fat has accumulated in the abdomen- sometimes being so deep it doesn’t show on the outside. There’s no pot belly or middle-age spread….. nothing to indicate any increase in risk of health problems. Of particular concern is fat that builds around vital organs, which is called visceral fat.
This fat produces compounds that can trigger inflammation and release fatty acids into the bloodstream. That’s different to the more benign subcutaneous fat (the fat you can pinch or jiggle) that tends to accumulate around the hips or thighs.
5 signs you could be ‘Skinny Fat’:
- You carry excess fat around your belly
- You have high blood pressure
- Your cholesterol levels are elevated
- You have insulin resistance or high blood glucose levels
- You rarely exercise and could improve your eating habits
How Common Is It?
Normal-weight obesity is growing. Australian research found waist circumference for individuals of the same body weight, height and age grew by 6.7 cm for women and 2.8 cm for men between 1989-2012. Roughly 1 in 5 women and 1 in 10 men, were obese according to waist circumference, even though they would not be detected as obese by BMI.
Many experts now suggest the definition of ‘obesity’ needs an update to account not only for weight, but also adiposity- in other words, body fat.
Why Is It A Worry?
Experts now know that people who have an obese waist circumference (greater than 88 cm for women or greater than 102 cm for men) but who don’t have a BMI that would put them in the obese category (30 or higher) still have an increased risk of heart disease, type 2 diabetes, high blood pressure and early death than those defined as obese by the BMI. That’s partly because visceral fat isn’t just sitting there dormant inside us. “Fat around the organs is definitely riskier than fat anywhere else in the body” according to Rozanne Kruger, Associate Professor in Dietetics and Human Nutrition at Massey University in New Zealand.
“This fat around the organs has been shown to increase the risk of cardiovascular disease, glucose intolerance, inflammation and insulin resistance”. Fat cells around the middle of the body produce inflammatory proteins that disrupt insulin regulation. This then increases the risk of type 2 diabetes. These inflammatory proteins also cause resistance to leptin- a hormone that regulates fat storage, appetite and how many kilojoules we burn.
What Causes It?
There’s a genetic component to normal-weight obesity- some of us are just more prone to an ‘apple’ body shape. But normal-weight obesity also develops over time. Diet and inactivity both contribute, even if they don’t cause weight gain. Researches looking at body composition say that younger, premenopausal women are particularly at risk of accumulating higher body fat, due to physical inactivity and unhealthy eating habits, such as dieting and fast-food consumption.
Our bodies also tend to change over time, too. As we age, we lose muscle mass, especially if we’re not regularly exercising those muscles. When we lose muscle, the proportion of fat in our bodies will naturally increase. Less muscle also means we’re inclined to gain more fat. It’s a bit of vicious cycle.
“Our metabolism slows as we age,” Dr Kruger says, “The moment your metabolic rate starts to drop, and you eat the same as you always have, you are likely to gain weight.” Menopause is a common contributor for women, as hormonal changes mean fat is stored more centrally than before. This, and a slower metabolism as we age, can boost weight gain and belly fat.
Stress also likely plays a role, with the stress hormone cortisol associated with higher levels of visceral fat. Plus, when we are stressed, we tend to not eat as well- and to exercise less.
How Do I Know I Have It?
To understand what’s going on inside your body, it’s very important to look beyond weight. Analysing your body composition is a sure-fire way to know whether or not you have normal-weight obesity. Most common is bioelectrical impedance analysis (BIA)- basically using body-fat recording tools- which is done in some gyms, health clinics and pharmacies.
Short of being analysed in this way, there are some signs that might give you some clue.
Check Your Shape
A good place to start is to assess your body shape. While we’re all genetically different, people who tend to gain fat around their chest and mid-section are likely to be more at risk of normal-weight obesity. They develop what we might call an ‘apple’ shape. If you have more of a ‘pear’ shape- with weight gains around the hips and thighs- you’re less likely to be carrying visceral fat.
See Your GP For A Blood Test
Getting regular cholesterol, blood glucose and blood pressure checks will all help show how healthy you are metabolically. Higher levels in some of these areas could point to normal-weight obesity.
Measure Your Waist
Your waist circumference is an easy measurement for a quick check. Run a tape measure around your middle. Note for men: this is not where your belt goes. It’s the point (further up) at the top of your hip bones, near your belly button. A waist measurement over 94 cm for a man, or 80 cm for a woman, could mean risky visceral fat.
How To REVERSE Normal Weight Obesity
Luckily visceral fat is something you can reduce. You may even find it easier than shedding the fat around your hips and thighs. “Visceral fat is often where people lose weight first”, Dr Kruger says. “But it’s not just changing your physical activity or changing diet- the answer is to change both. If you do that, you have a bigger chance of reducing body fat”. Here are some handy tips:
1 Tweak Your Diet
Focus on a healthy diet full of unprocessed whole foods, vegies and not too much sugar, refined carbs or saturated fat. This will fuel your body and energise your day, too. Keep an eye on portion sizes- and stick to the half plate of vegies model. Cutting down on alcohol is a big help. If you’re over-keen on sugary drinks, cutting back is a great idea too.
Higher intakes of sweet drinks have been associated with increased levels of visceral fat
2 Move Every Day
Engaging in regular exercise is crucial to burning visceral fat. Any movement is good-walking, running, swimming- just get moving daily for at least 30 minutes.
3 Lift Weights
Building muscle is a great way to reduce body fat, and a powerful way to reduce visceral fat in particular. The more muscle you have, the more energy you burn, even when you are not exercising. This gradually helps reduce your body’s fat stores. Being strong is also great for your bones, especially as you age.
4 Manage Stress
When you’re exposed to chronic stress, your body is bathed in a flood of the stress hormone called cortisol. An excess of cortisol increases the likelihood of storing fat around your middle.
5 Commit To Sleep
Not getting enough sleep can increase your risk of heart disease and type 2 diabetes- not to mention ramping up your appetite for sugar/fat-rich foods the next day. Aim for a consistent bedtime, and avoid skimping on sleep.