What is body fat percentage and how can you measure it?

If you have recently decided to improve your health or try to lose weight, you might be looking at the scales or measuring tape and feeling a little overwhelmed.

Health and progress look different for everybody, and numbers are not always a perfect way to measure your well-being.

However, if you are just starting out or have a particular goal, data and numbers can be useful tools to gauge your starting point and measure progress. But they can also be confusing, so that's where we come in.

Here's what you need to know about body composition, weight, and body fat percentage — and what they all mean for your health.

What is body fat percentage?

One term you might have heard of is body fat percentage. The weight of your body is made up of a combination of things like bone mass, muscle mass, different types of fat, skin tissue, and water [1].

Body fat percentage refers to the percentage of this weight that is made up of fat.

Fats and lipids play an important role in functions such as digestion, energy and metabolism, and they act as an energy provider and energy reserve [1]. They also regulate hormones, reproductive functions, and water balance.

You need body fat to complete these functions (this is called essential body fat) but too much or too little fat can be dangerous, which is why it is important to have a general idea of your body fat percentage.

What's a healthy body fat percentage?

We know everybody is different, and health can come in different shapes and sizes — so you might be wondering, why does body fat percentage matter?

As we've mentioned, fat plays an essential role in the body, so while it is important not to have a high body fat percentage, low body fat percentages can actually be dangerous as well.

If you don't have enough essential body fat, you can experience issues with your immune system, be more susceptible to injuries, struggle to regulate your temperature, and experience hormonal issues [1].

Men typically require a lower body fat percentage than women due to different hormonal needs and life and reproductive functions.

Women require more essential body fat to support things like childbearing, and if their body fat percentage is too low, they can develop conditions such as amenorrhoea which can prevent them from being able to get pregnant [2].

The ideal body fat percentages vary depending on factors like age and sex, but the American College of Sports Medicine suggests essential fat values are around 3% for men and 12% for women.

The guidelines suggest a body fat percentage of 16-25% would be considered healthy for women aged 20-39, and those aged 40-49 can aim for 19-28% [3].

For males aged 20-39, body fat percentages of 7-21% are recommended, increasing to 14-23% for the 40-49 age bracket.

If your body fat percentage is higher than the recommended range, you could have a higher chance of experiencing dangerous health issues and conditions.

What are the health risks of having a high body fat percentage?

Having a higher body fat percentage can put you at risk of a number of serious health issues.

There are different types of body fat we all have; subcutaneous and visceral [4]. Subcutaneous fat sits directly under the skin around the waist, hips, upper back, buttocks, and thighs, and is the fat we can see, pinch or grab.

Visceral fat is often more dangerous (sometimes called 'toxic fat'), and is a white fat that accumulates deep in the abdominal cavity and can wrap around your vital organs, including your heart, liver and intestines [5].

Having a high amount of this is a sign of metabolic syndrome, which increases your risk of cardiovascular disease, some types of cancer, and insulin resistance [5].

Together, these also increase your risk of other issues such as strokes and diabetes, and too much visceral fat in the belly can increase your risk of dementia, asthma, liver disease, fertility problems, lower back pain and osteoarthritis.

Ways to measure body fat percentage

There are a few different ways to measure or estimate body fat percentage, and one option that you can do yourself at home is body circumference measurements [6].

Your waist circumference can indicate how much fat is inside your belly and around your organs. You can check this by placing a tape measure halfway between your lowest rib and the top of your hipbone — roughly in line with your belly button.

If the measurement is higher than 80cm for women and 94cm for males, this indicates you might have an unhealthy amount of visceral fat.

However, it should be noted that waist measurements only apply to adults, and are less accurate for people from non-European backgrounds and those with medical issues that impact the abdomen [7].

Another way to estimate body fat percentage is your waist-to-hip ratio, which can be done by dividing your waist by hip measurement.

While this may be a better indicator than waist alone, the World Health Organization has found healthy ratios can vary depending on factors such as ethnicity and different natural body shapes.

Other ways of measuring body fat include [4]:

• Skinfold tests. These are done by using a calliper to measure the thickness of skin and fat in specific areas of the body and applying equations to calculate body fat percentage based on these numbers.
• Underwater weighing. Also referred to as Densitometry or Hydrostatic Weighing, this involves being weighed firstly on dry land, and then in water. Fat and muscle "float" differently, so experts can use formulas to calculate body fat percentage, body volume, and body density.
• Dual-energy x-ray absorptiometry (DEXA) scan. This involves using 2 X-ray beams to scan the body and calculate estimates of fat-free mass, fat mass, and bone density.
• Bioelectric impedance analysis (BIA). BIA equipment sends a small electric current through the body and measures the resistance, as there is more resistance from fat than lean muscle mass or water. These measurements can then be used to estimate a person's body fat percentage.

These tests are generally more complicated or require specialist equipment, and can generally only be done in health centres or research settings.

Body fat percentage vs body mass index

Body fat percentage and body mass index are both indicators of overall health and can be used to estimate whether you are a healthy weight, but they are actually two different things.

Body mass index, also known as BMI, is the index of body weight for height. It is often used as a reference point by medical professionals to assess a patient's chances of developing conditions including diabetes, high blood pressure, and other metabolic conditions [8].

A healthy BMI is generally considered to be between 18.5 and 24.9 and is calculated by dividing your weight in kilograms by the square of your height in meters [9].

It does not take into account factors such as bone density, water, or muscle mass.

For this reason, it is not always an accurate way to measure health and should be used as more of a guide or way to estimate body fat — for example, many elite athletes have a high BMI due to their muscles, and they are some of the healthiest people in the world [10]!

BMI is also less accurate for certain ethnic groups, people under 18, people with certain physical disabilities, and pregnant women [7].

Body fat percentage, on the other hand, can offer a more accurate indicator of whether a person has a healthy amount of body fat, and is likely to face weight-related health risks.

Tips for reducing body fat

If you are concerned about your body fat percentage and believe you might not be at a healthy weight, there are several steps you can take to reach an ideal body fat percentage.

Firstly, if you have not done so already, it is a good idea to measure body fat and work out where your body is currently sitting, and where you want to be.

Lifestyle factors like increasing your exercise to at least 30 minutes each day, eating a healthy diet, getting enough sleep, and reducing consumption of sugary drinks and alcohol can help with weight loss and improving overall well-being.

Reducing your body fat percentage into a healthy range is often easier said than done though, and a weight loss programme like Juniper's Weight Reset could make all the difference if you need some extra support.

The holistic programme pairs clinically proven medications with dietician-led coaching and support to help make lasting changes, and has helped thousands of British women achieve results.

Kickstart your weight loss journey with Wegovy or Mounjaro, two groundbreaking weight loss injections that mimic the GLP-1 and GIP hormone respectively to help control cravings, delay stomach emptying, and keep you feeling fuller for longer.

Plus, we have a team of expert dietitians and health coaches you can consult with, to help you work through any challenges you're experiencing during your weight management journey.

We help you make lifestyle and habit changes to help increase your fitness levels and promote eating a balanced diet by providing you with one-on-one health tracking and weekly check-ins with your clinician to track your biometric, mental and physical health, continuously making adjustments to your programme to suit your individual needs.

This holistic approach sets you up for sustained weight loss, rather than a quick-fix solution.

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