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.
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.
Monday 21st of December 2020
I am Female 32y old height 1.65 m weight 58 kg fat weight 22.376 kg lean weight 33.619 kg android 34.8% gynoid 47.2% A/G ratio .74 BMC 2.657 tissue fat % is 40%
I need your advice plz ,as you are the only doctor with logic thoughts .
I am in good health ? should I gain more muscles and lose fat ?
any advice plz.
Dr Bill Sukala
Tuesday 22nd of December 2020
Hi Nesreen, I cannot tell you if you're healthy just by body composition numbers. Body composition (how much muscle and fat you have) is only one single biomarker of health. If you're concerned, the best course of action is for you to make an appointment with your doctor and have a physical health screen conducted. The reason for this is that it is possible to carry body fat and be healthy on the inside (i.e., normal blood pressure, normal blood sugar). So it's not always a simple case of "too much fat = unhealthy." It really depends on the individual and their overall lifestyle habits. Bottom line: I would suggest that you not get too fixated ONLY on body fat and muscle, but look at the big picture. Once you have a health physical completed, at least then you will have some concrete starting numbers to work with and then you can make a plan (i.e., making healthy changes to your exercise, eating habits, reducing stress, etc).
Hope this helps.
Kind regards, Bill
Monday 8th of May 2017
If I workout and play outside I end up with a great, lively body, with 20%body fat. And the way I prefer it to look eg athletic. But medium term anything below 22% halts my she-flows (aka menstrual cycle ) and long term I discovered that it's an.energy deficit that stresses other hormonal systems including adrenal andthyroid. RED-S is an easy trap to fall into. If you are not a competitive athlete, and just like moving your body for fun, then you may not realise you need to eat like an athlete. Many female athletes welcome a loss of menstrual cycle but don't realise the long term effects. I saw a news report saying that sumo wrestlers can be healthy because they overeat but also exercise, and that causes adipose but visceral fat. Not sure of the validity!
Dr Bill Sukala
Tuesday 9th of May 2017
Hi Claire, Yep, you make a good point. Everyone is a bit different, but after running countless dexa scans on athletic women, I can tell you one thing's for sure. There are a lot of really ripped women out there with anomalously low body fat who can barely remember when their last menstrual cycle was. So whilst they might be the Instagram muses for many aspiring female bodybuilders and figure competitors, there is an unspoken downside to it all that is often ignored (oftentimes wilfully). The threshold at which a woman loses her menstrual cycle varies from person to person, but it's important for each woman to know where that line is. As for the sumo wrestler, not sure. I haven't seen that study! Thanks for taking the time to leave a comment :)
Thursday 19th of January 2017
All forms of bodyfat percentage measurement currently being embraced by fitness professionals and enthusiasts are actually highly variable and potentially wildly inaccurate at the individual level. DEXA is not purely empirical, contrary to common belief. It too relies on a predictive algorithm that assumes your most likely fat mass for your age and gender (ie. according to general norms).
Dr Bill Sukala
Friday 20th of January 2017
Hi Alison, You'd be correct. The different methodologies can give massively disparate results. I've taught exercise physiologists and personal trainers all the different testing modalities and have had each student measure all their classmates and then I plotted them in a spreadsheet and graph to show how much of a difference there is between assessors. It's huge. At least with DEXA, provided proper protocol is followed, we tend to see more intrasubject accuracy and reliability. But if you really want 100% accuracy, then cadaver dissection is the way to go. But unfortunately you don't get many volunteers for that!
Wednesday 31st of August 2016
Hi, in answer to Lisa; I'm 49 work a mad schedule in the corporate world of 12-18 hours a day, need very little sleep but made a point a taking 3 hours a day for me. I work out 5-6 times a week mostly weight (hate cardio although I would do a weekly spinning class) and over the last year decided to reshape my body from OK to really good! I'm 1.75m and my weight fluctuates between 55 and 58.5kg with a body fat mass around 22%. On paper not bad in reality felt flabby and out of shape. I worked in 2 things diet and training. I started with dietician to make sure I would not do anything crazy and get in the right path and then made it fit for me. I increased the amount of lean protein (egg white omelette, fish, little meat, low fat protein-whey impact isolate unflavoured), kept loads of green veg, added fat to my diet (avocado, nuts), always been super low carbs, few berries and chocolate every day (can't live both out my super dark few squares), virtually no alcohol champagne on Friday! Skinny cappuccino and tea are on every day! I changed my training to heavier weights with less reps (don't want bulk) and working out with an ex body builder who controls my posture and counts the rep (he does not take no or I can't as an answer). In short after one year I have not lost weight, I'm now 57kg but my body fat has dropped to 7.5% my body is pure lean muscle does not look skinny or over muscular and the last full medical checkup gave me a physiological age of 22-24. I still need to do more work out to tighten my core further but the transformation is amazing no flab in sight and the bad circulation with swollen ankles has almost disappeared. It's a lot of discipline but so worth it; I did not aim at a such a low body fat it just happened and thank god I'm not looking skinny probably c'ause I did not lose weight and I'm passionate about food and cooking which is the core of a healthy diet. Anna
Tuesday 19th of April 2016
Hiii Bill...I'm a fitness trainer n a dietician.... I'd like to understand the concept of visceral fat a lil better.. In d sense if anyone s vis.fat is very low n is going down lower with a n exercise regime....how advisable is it to have very low visceral fat.... I.e..from 2---10..is d normal range but if someone has less den 2....how do we get to increase dis levels..pl advice
Dr Bill Sukala
Wednesday 20th of April 2016
Hi Bella, I think normative ranges for anything can be a general guide, but you always have to consider the individual and what's healthy for that person. As I said in my article, what's normal and healthy for one person could plausibly be too much (or too little) for someone else. In the example you've referred to, I'd be looking into if the person's health is compromised due to their fat being too low. If not, then why fix something that isn't broken?