I’ve run a LOT of DEXA body fat scans during my health career, but even with a trained eye, I can guarantee you can’t always tell who’s fit or fat just by eyeing up the person.
Some people appear to have a lot of fat when, in fact, their fat percentage is low and they carry a lot of muscle.
Others look skinny but actually carry a lot of fat and little muscle.
The DEXA comparison image shows a man with a lot of muscle and very little subcutaneous fat and a woman who carries comparatively more fat and less muscle.
I get looks of despair when people find out their percentage is higher than they thought and tears of joy when lower than expected.
However, body composition results need to be properly interpreted and put into context for each individual.
Please read my article on fat mass index which sheds light on this common misunderstanding.
What is a “normal” body fat percentage anyway?
I don’t like drawing a dichotomous line in the sand when it comes to so-called “norms” charts.
I think it’s important that people understand they’re only a general guideline and that what’s too much or too little for one person may be different for the next.
Whether a woman is 30.9% (“acceptable”) or 31.1% (“overweight”), the difference is purely academic and she probably won’t look much different (or suffer a massive heart attack) with the extra 0.2 percent pushing her into the next classification.
How much is too much fat?
Clients often ask me if they have too much body fat. My answer to this question is always the same: too much fat for what?
The question must be further qualified by asking WHY their body fat percent is important to them.
- Are they focused on their body composition and its relationship to health problems?
- Or are they only concerned about aesthetics and wanting to look like a ripped fitness model?
How does fat relate to health?
Excessive fat is associated with many health problems including type 2 diabetes and heart disease.
However, our understanding of body fat has evolved over the years and we now understand that it’s not always the total amount of body fat but where it’s located on your body.
Visceral fat refers to the deep belly fat inside your abdomen which wraps around your organs and secretes substances into the bloodstream known as cytokines.
There are many different types of cytokines and they exert a variety of effects such as blood vessel constriction (high blood pressure) or inflammation which can contribute to the development of both diabetes and heart disease.
How much visceral fat can I have before it causes health problems?
Research has demonstrated that when we look across the population and stuff everyone under the bell curve, a visceral fat area ranging from 10 to 100 cm² is considered normal and at around 100 cm² the risk for heart and metabolic problems begins to increase.
I think it’s important to note that the visceral fat threshold for the onset of disease will vary from person to person.
For example, a man with a strong family history of early-onset heart attacks on the male side of his family might have a lower individual visceral fat threshold of, say, 80 cm².
On the other hand, a woman with the longevity gene and a pack a day cigarette habit could plausibly have a threshold of 130 cm².
Fat distribution: apple versus pear body shape and health risk
We tend to associate an apple-shaped body (more central fat) with health risk and a pear-shaped body (more hip and thigh fat) with a comparatively lower risk.
However, a study out of UC Davis suggests that lower body fat is associated with an increase in cytokines linked to the development of heart disease and diabetes.
This is just a single small study and would still need to be corroborated by more trials which can establish a cause and effect relationship between lower body fat and health risk.
Low body fat, aesthetics, and public perception
I’ve seen DEXA reports on women with 20% body fat and a visceral fat area of 20 cm².
These were fit women who exercised daily, didn’t smoke, drank little alcohol, and were careful with their diets.
Yet no matter how much I reassured them, they were convinced their body fat percentage was too high and they were determined to get down to 15%.
This raises questions about the battle between body fat, aesthetics, health, and the role the media and advertising play in distorted body images.
The nonstop barrage of subliminal “thin is in” and “nobody will love you unless you’re perfect” health messages have created a disconnect between what ACTUALLY constitutes a healthy fat percentage and what people THINK is a healthy fat percentage.
See my related article on media health messages.
How low is too low for body fat percentage?
So how low can your body fat go before it causes problems?
As with visceral fat, the low-end threshold at which your body fat is “too low” is different for everyone.
I would say that, for women, when body fat percentages approach the low teens, or for men down in the single digits, then it’s time to pay attention to any changes in your body’s physiology, such as a loss of menstrual cycle, or feeling tired, getting sick more frequently.
Don’t forget, fat is your friend
Despite all the bad press it receives, fat is important for our survival and normal biological functions.
Don’t get too hung up on norm charts and don’t compare yourself to the models on the covers of fitness magazines.
Assume a more health-focused perspective and work on keeping your visceral fat levels to a minimum.
And remember, body fat is only a single biomarker and other lifestyle factors such as exercise, diet, smoking, and stress must be taken into consideration.