Many tend to assume that body fat is either good or bad for you. But it’s more complex than that.

While research supports the idea that people with high body fat levels are more likely to develop cardiovascular disease and metabolic syndrome, body fat levels that are too low are not necessarily good for you either.  The reality is that there’s more to body fat than meets the eye.

Essential vs. Storage Fat: What’s the Difference?

To start, there are two main types of body fat: essential fat and storage fat.

As its name implies, essential fat plays a critical role in your overall health and cellular processes.  In Exercise Physiology: Nutrition, Energy, and Human Performance, essential fat is described as,“…the fat in heart, lungs, liver, spleen, kidneys, intestines, muscles, and lipid-rich tissue of the central nervous system and bone marrow.”

As metabolic fuel, essential fat makes sure that you have sufficient energy reserves and it helps conserve body heat when needed. It also protects your internal organs and joints from injury, acting as a soft, fluffy cushion.

As chemical messengers, they help ensure that bodily processes like metabolism, growth, and immune functions are going as smoothly as planned. Finally, essential fat plays an important role in a woman’s reproductive abilities.

Normal bodily functions will go haywire if essential fat falls below the recommended minimum level of 5% in men and below 15% in women. Women have high essential body fat ranges as a result of childbearing and reproductive needs.

Meanwhile, nonessential or storage fat is accumulated body fat for energy reserves. This is the fat that you notice in your body.

What is Body Fat Percentage?

Put simply, body fat % is the amount of fat you have in your body, excluding your fat-free mass (or lean body mass). Your fat-free mass is made up of your bones, organs, muscles, and body water.

Your body fat percentage (also known as percent body fat) reflects how much of your weight is made up of body fat. It is calculated by dividing the weight of your body fat mass by your total weight. Currently, there is no official standard for acceptable body fat percentage values.

At InBody USA, we recommend a body fat percentage range of 10-20 percent for males and 18-28 percent for women.

How Certain Body Fat Percentages Look in Men and Women

Before we go through the pitfalls of dangerously low body fat, let’s take a look at the following five body fat percentage ranges in both men and women.

Excessive: >25% (Men); >32% (Women)

Excess fat will be present in the entire body — often concentrated in the abdominal area, thighs, and hips. 

Individuals within this range of body fat percentage have an increased risk of metabolic or cardiovascular disease. Obesity is also linked to poor self-esteem as well as low energy levels.

Overfat: 20-25% (Men); 28-32% (Women)

Men and women who fall in this body fat percentage range may not have as much excess body weight as those in the previous category but still have excess body fat.

While it is true that some people in the overfat category will be overweight, it’s also possible to have a normal or average body weight but have too much body fat. This is also known as sarcopenic obesity or skinny fat.

Like their obese counterparts, possible issues include low energy levels, higher risk of metabolic syndrome and cardiovascular disease, poor self-esteem due to physical appearance, and a shortened life expectancy.

People who are skinny fat are also particularly vulnerable to health problems because they have similar body compositions as people who are overweight, but may have very few visual indicators that can warn them of their health risks.

Average Fitness: 15-20% (Men); 23-28% (Women)

Men in this body fat percentage category are often described as moderately lean and fit. While muscle definition may not be obvious, outlines and striations may slightly appear.  A bit of vascularity may be present in the arms.

For women, this category is neither slim nor overweight. With more body fat around the thighs and buttocks, curves will begin to form in the hips.

Both men and women may have some muscular definition but it may take on a softer appearance. Off-season athletes typically fall in this category. People in this category typically enjoy high energy levels, better sleep, and good overall health. They may also look good in tight fitting clothes which in turn leads to better self-esteem. Health issues due to excess body fat are less likely to develop over time.

Athletic Fitness: 10-15% (Men); 18-23% (Women)

Men and women who fall in this body fat percentage category have the classic beach body look. They are lean, muscular, and clearly fit. There is little fat to pinch and muscle definition is particularly obvious in the shoulders, arms, and abs. Professional athletes may fall into this category.

Vascularity may appear in the arms but it may not as pronounced in the legs among men. Women with this body fat percentage may have fat in the arms and legs but it’s not as obvious than those with higher body fat percentages.

Besides looking really fit, individuals with this body fat percentage tend to enjoy excellent overall health and well-being. They also experience less cravings due to regular physical activity and strict adherence to a diet that works for them.

Exceptional Fitness /Bodybuilder Range: 3-10% (Men); 12-18% (Women)

This body fat percentage category often includes bodybuilding competitors and fitness models.

Muscle definition tends to be high in both men and women and there is very little fat. Bodybuilders, for instance, may aim for the extreme low end of this range on cycles when they are competing because in order to have a competitive look, they require next to no body fat.

This is an incredibly difficult body composition to maintain consistently over time, especially at the lower end of this range.

Throw into the above numbers, other factors like age and actual fat layout or distribution across the body, and you can see why it can become such a confusing topic.

Health Risks and Dangers of Low Body Fat in Adult Men and Women

Men who have less than 6 percent body fat and women with less than 16 percent body fat are considered too low. They are typically bodybuilders in contest training or fitness models on the day of their photoshoot. These individuals have gone to great lengths such as going on a strict diet and exercise regimen for weeks.

You might be thinking that these body fat percentage ranges are actually healthy because they are still above the essential fat values. 

But, not so fast.

In a 12-month case study conducted by the International Journal of Sports Physiological Performance, researchers tracked the body composition and physical state of a male competitive bodybuilder whose body fat percentage was around 4.5 percent for competition.

Researchers indicated that several negative outcomes consistent with overtraining, such as decreases in physical performance and reduction in immune system function, had occurred.

A more recent investigation showed that in order to achieve these extremely low body fat levels, these athletes had to rely on steroids and other drugs to help them achieve their goals, common practices within the field of bodybuilding/figure competition. What is now becoming clear is that these practices, while useful for helping attain the desired look, are associated with significantly greater risk of heart disease and liver dysfunction.

These athletes went on to explain that these negative physiological changes are unfortunate, but necessary, repercussions of competitive bodybuilding.

Female bodybuilders, on the other hand, experience an additional side effect of having an extremely low body fat percentage — the temporary stop of menstruation or amenorrhea. It forms one part of a condition known as the Female Athlete Triad.

Additionally, competitive female bodybuilders have been shown to share the same eating-related habits as those with bulimia. They may shun social events that involve dining out and may not have the time for other activities. Female bodybuilders may also experience other reproductive and fertility issues.

Bodybuilders’ Bodies Are Not Ideal

Despite their impressive physical appearances, bodybuilders do not have an ideal body composition.

Their sports demand they put their body through stress to the point where normal biological functions become impaired. Therefore, looking like a bodybuilder should not be a goal (unless you’re a bodybuilder).

Can Low Body Fat Improve Sports Performance?

While low levels of body fat seem to be associated with improved sports performance, body composition alone is not a great predictor of athletic success. There is little evidence for any health benefit when men drop under 8 percent in body fat and when women drop under 14 percent body fat.

Additionally, trying to achieve a body fat percentage that is similar to professional bodybuilding goals can lead to a slew of health issues and complications like impaired body thermoregulation, increased risk of injury, fatigue, loss of muscle tissue, and suboptimal body performance.

The Takeaway: Going Beyond Body Fat Percentage

Although your body fat percentage is a significant and useful metric, relying on it alone will not provide you with solutions or answers that can improve your overall health and fitness.

You will need more specific values than your body fat percentage and weight such as your skeletal muscle mass, visceral fat, and even segmental lean analysis. This will not only help you maintain a healthy body fat percentage in respect to a healthy weight,  but it can also help you figure out if you have muscle imbalances, reduced muscle mass, or are not eating enough.

Your body is a very complex system of specific components working together. Think of body fat percentage as merely a single tree in a large forest. It’s important to get as much information as possible about the health of the entire forest and not just for one specific tree.

By completing regular body composition analysis you will not only have a much better understanding of this, but it is a method by which you can track your progress if improvement is your goal.

Contact My Body Composition Solutions for more information.

Disclaimer: This article should not substitute professional medical advice. When starting a new diet or exercise plan, always consult your physician and exercise professional first.

Information in this article has been extracted and edited from InBody USA ‘Is It Healthy to Have a Low Body Fat Percentage?”

published on August 9, 2018 and written by Kyjean Tomboc, a nurse turned freelance healthcare copywriter and UX researcher.

 This article includes words and phrases that link to several other information resources.