Body Fat Measurement: The Options that are Best for You

By Katie Mark Sep 22, 2015

pinch_fat

Measuring our body fat and pinpointing its location on our body is one of the best ways to assess our health status and health risks. Fortunately, there are options to measure body fat – from body calipers, to the gold standard of DXA scans. In this blog we review the best options in total body fat measurements that the general public can do on their own, including information on how fat distribution within that percentage matters for health.

Skinny Fat vs. Strong Physique: Rethink Weight Loss

Are you puzzled as to why the mirror reflects a soft physique even though you just lost weight? Weight loss may not always be a good thing. Losing weight may come from fat, water or muscle (also referred to as lean tissue). However, now that we’ve explained the distribution of fat, it’s best to focus on losing visceral fat and maintaining – even gaining – lean body mass.

Lean body mass is everything that is not fat, such as the weight of: muscles, bones, fluids, tendons, ligaments and internal organs.

An obvious goal for weight loss is to lose fat, but that does not always result depending on the strategy you use. In fact, majority of weight loss approaches that reduce fat mass also result in a loss of lean body mass. This is exemplified when following a low carbohydrate diet in which the initial weight loss is usually from water. This is because 3 to 4 grams of water are stored with every gram of glycogen (glucose storage in the liver and muscle).

Summary: The weight scale does not tell an accurate story. Weight loss may not necessarily come from fat. A weight loss goal should focus on reducing body fat percentage to improve body composition, which increases lean body mass.

Cutting Further Into the Fat of Men vs. Women

Females (Gynoid) vs. Males (Android)- Women have a higher body fat percentage and different fat distribution compared to men. The gynoid fat distribution – commonly referred to as pear shape – deposits adipose tissue in the hips and thighs (gluteofemoral fat) of women. The android fat distribution (apple shape), predominantly found in males, is classified as mostly visceral fat and is found in the upper thoracic region.

Insulin is crucial in metabolism and insulin resistance may be the missing link in obesity, cardiovascular disease and type 2 diabetes. Android fat distribution is mostly associated with cardiovascular risk in comparison to gynoid. The gynoid distribution actually provides protection against diseases like type 2 diabetes and atherosclerosis. Android obesity is associated with metabolic complications such as insulin resistance, dyslipidemia (an increase in serum cholesterol and/or triglycerides that may lead to atherosclerosis) and hypertension.

Men usually have a higher lean mass and greater visceral fat and liver fat tissue while women have higher general adiposity.  The gender differences in fat tissue distribution might facilitate a more insulin-sensitive (how well your body responds to insulin) environment in women because both visceral and liver fat (as seen more in men) are associated with increased insulin resistance.

andriod_and_gynoid_fat

Caption: Body fat storage locations on men is traditionally at andriod locations, but fat stores in the lower body is possibility as well.

Men who are more physically active usually have less body fat than men who are less active, but this is not necessarily true for women. One study found that exercise is not associated with a significant fat loss in women. An explanation for this relationship between physical activity and body fat in women could be because women tend to increase their food intake more so than men.

 Geer and Shen (2009) suggest that body composition has a stronger relationship to the type of food intake in women than it does in men. However, the gender differences between energy expenditure and body composition has not been completely determined by food intake or differences in metabolism.

Summary: Women have a gynoid fat distribution (fat deposits in thighs and hips). Men tend to have an android fat distribution (visceral fat associated with the upper body). Android fat is associated with cardiovascular risk more than gynoid fat.

Track Your Body Composition, Not Just Your Weight

Measuring body fat helps identify health risks and evaluate body composition. A weight scale provides us with a number signifying the weight of ALL our body tissues. Body composition provides us with percentages of body fat and lean body mass.

It is important to note that body mass index (BMI) and waist circumference (WC) do not assess body fat percentage. BMI is calculated by dividing weight in kilograms by height in meters squared. Understanding body composition is important to understanding weight loss. For example, someone might weigh more than BMI suggests and may be classified as “overweight.” Yet, body composition is not under consideration when using BMI. The person could have a low body fat percentage, which would classify them as lean. Athletes are a prime example of this because they have more muscle mass. And muscle weighs more than fat.

Conversely, someone who weighs less than what a BMI indicates could be classified as “thin,” but they could actually be carrying more body fat. This is similar to the idea of “skinny fat.”

It can assess our risk for obesity-related complications, but it still does not tell us the composition of our weight.

WC also suggests our increased risk for obesity-related health problems because of the location of excess fat – in the abdominal area where the dangerous visceral fat is located.

Summary: Weight loss does not always come from fat. Focus should be on reducing body fat percentage to build a leaner body composition. Lean body composition, not solely weight loss, should be your primary gauge of your physique.

How Can You Track Body Fat?

Body fat assessments vary in their precision and accuracy. Common anthropometric measures include: weight, waist circumference and skinfold measurements using skin calipers. To measure WC, stand relaxed and place a cloth tape measure around the smallest part of the waist.

More complex methods include: bioelectrical impedance analysis (BIA), the BOD POD and dual-energy X-ray absorptiometry (DEXA or DXA). You should a methodology based on what is appropriate for you because each methodology has pros and cons.

 Skin Calipers: Quick and Easy

A couple of bucks can get you skin calipers. This feasible skin fold assessment gathers measurements from a few body sites. Following a pinch of the skin, the thickness of the skin fold is measured using skin calipers. Measurements, with specific protocols, are taken from the chest, arm, abdominals and thighs. The measurements are then plugged into an equation to estimate body composition.

calipers

Body fat percentage can be determined within minutes, but the margin of error should be considered. This type of method requires accurate readings. It is suggested to measure from the same spots each time.

Fortunately with this measurement, a study found that using skin calipers to calculate total body fat percentage did not significantly differ from the value calculated using a portable ultra sound. Yet, skin calipers provide regional body fat data because it does not measure deep belly fat. Therefore, it is a good relative measure of body fat.

Bioelectrical Impedance Analysis (BIA)  

BIA scales range from simple – a scale with electrodes under the feet - to complex – a handheld scale with electrodes. The non-invasive BIA produces rapid results and can yield <1% error when repeating measurements.

BIA relies on electric current that flows at different rates through the body depending on body composition. An electric current can flow through the body because of the body’s large composition of water with ions. The body also consists of body fat, or non-conducting material, which resists electric current and contains little water.  

BIA estimates body fat by measuring how easily the current moves through the body. Body fat will resist electric current more than body protein. A voltage drop occurs in response to impedance. Following BIA measurement, predictive equations considering weight, height, sex and age estimate free fat mass.

skulpt-female

According to the skulpt website, the The technology behind the device is called electrical impedance myography or EIM for short. In addition to estimating body fat, it uses a score called MQ to measure muscle quality, a unique measurement the company believes consumers should track.

The BIA approach to estimating body fat is more limited in evaluating body composition in individuals compared to groups. BIA has higher sensitivity and specificity for yielding average adiposity for certain groups of people. Predictive equations for BIA have been developed for certain groups of various age groups for both sexes, including samples from Caucasian populations in the U.S. and Europe as well as African Americans and Hispanics.

The BIA calculations used for an individual’s body fat can vary by 10% of body weight due to differences in methodologies and machines used. Therefore, the validity of these equations should be considered because it may affect the amount and direction of measurement error in BIA.

Another limitation to BIA is that it does not measure belly fat, the most dangerous fat. This is because electric current tends to follow the path of least resistance in the body. BIA measures free fat mass only, which makes it a less desirable body fat measurement tool for individuals.

The BOD POD 

The $30,000 BOD POD is an egg-shaped chamber that requires 3 minutes to detect the smallest changes in body fat and lean body mass using air displacement. During the assessment, the door will open and close for two 50-second assessments. The air displacement calculates body mass, volume and density.

The_Bod_Pod

The BOD POD estimates body fat, and InsideTracker's own Ryan Cohen is seen here getting his own composition tested. Ryan is a very data driven fitness and health consumer.

One study compared percent fat estimates between the BODY POD and DEXA. A significant mean difference of 2.2% was found among 160 men. The study could not determine what accounted for the difference. Also, as body fatness increased, the difference also increased.

Another study used 30 Division I collegiate track and field athletes to compare the accuracy of the BOD POD to skinfold measurements and DEXA. The percent body fat differed significantly between the BOD POD and DXA. The percent body fat between the BOD POD and skinfold measurements did not significantly differ.

There was a high correlation between percent body fat taken from the BOD POD and percent body fat taken by skinfold measurements. The percent body fat obtained from the BOD POD and from DXA had a poor correlation. In conclusion, THE BOD POD and skin calipers produced similar results whereas the BOD POD and DXA did not.

Dual-Energy X-Ray Absorptiometry (DEXA or DXA): The Gold Standard

DXA – which provides scanning like an X-ray – provides a highly accurate detail on fat and lean body mass distribution for $125 - $150. Results are quick as a single scan passes over the body while lying face-up on a table dressed in snuggly fit clothing.

Dexafit_Scan

There are numerous benefits to DXA. DXA is considered the most accurate and valid body composition tool because it considers bone mineral content when estimating body fat and muscle.

DEXA scans are also the ideal tool to evaluate different areas of fat distribution to determine the android/gynoid fat ratio, which is independent to BMI. DXA can accurately and simply assess the distribution of body fat associated with increased insulin resistance.

DEXA is a suitable tool for measuring body composition in team sport athletes. A study using 36 professional Australian football players tested two consecutive DXA scans. The DXA scan demonstrated precise measurements for fat-free soft tissue mass and bone mineral content.

In comparison to skin calipers, DXA is the way to go. One study found that skin calipers significantly underestimated body fat percentage in women compared to the DXA.

The biggest benefit of DXA is that it is best for assessing android/gynoid fat distribution, which better predicts health risks. The location of body fat is the most critical determinant of health risks rather than generalized adiposity – as seen with BMI and other body composition tools. The company DexaFit is already using DXA scans for their clients because it's the best option for body composition. Adam Kadela, the DexaFit Co-Founder, expressed the value of having the best technology for evaluating body composition.

"The greatest benefit with DXA is its consistent reliability from scan to scan, and its ability to objectively detect subtle changes in body composition. Couple these merits with its three-compartment analysis and ability to display fat distribution by region -- specifically your visceral fat tissue -- and no other method can compete as a better benchmark for tracking progress and evaluating your overall health."

 DXA scans are convenient ways to take control of one's health and performance, and offer the important connection of bone health as well as location of body fat, something no other option can do.

Summary: Skin calipers are an accessible, cheap option for calculating body fat, but its inability to measure visceral fat is a major drawback. BIA and skin calipers are good at predicting body composition.  If BOD POD or DEXA are not feasible options, skin calipers can at least obtain a body fat estimation. DXA is the most accurate in site-specific body fat, and it provides an android/gynoid fat ratio, which better predicts health risks.

What Should I Do With My Body Composition Data?

Each measurement tool for body composition has its respective restraints, but each has an important outcome. Assessing body composition will help identify your health risks, evaluate your current approaches to nutrition and exercise and/or individualize a new exercise or nutrition program.

Acknowledge that the number on a weight scale may stay the same, but there may be changes in both lean and fat mass. These body fat measurement tools combined with biomarker monitoring from InsideTracker are sure-ways of letting you know whether or not your diet and workouts are actually working.

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References 

1.Volek, J.S., Quann, E. E., Forsythe, C.E. Low carbohydrate diets promote a more favorable body composition than low-fat diets. National Strength and Conditioning Association. February 2010(32)1.

2.Bredbenner, C.B., Moe, G., Beshgetoor, Kelley, D. (2016). Wardlaw’s Perspectives in Nutrition. New York, New York: McGraw-Hill Education.

3.Geer, E.B., Shen, W. Gender differences in insulin resistance, body composition and energy balance. Gend Med. 2009;6:60–75.

4.Donnelly, J.E., Hill, J.O., Jacobsen, D.J., et al. Effects of a 16-month randomized controlled exercise trial on body weight and composition in young, overweight men and women: The Midwest Exercise Trial. Arch Intern Med 2003;163:1343–1350.

5.Dehghan, M., Merchant, A.T. Is bioelectrical impedance accurate for use in large epidemiological studies? Nutr J. 2008;7:26.

6.Samsell, L., Regier, M., Walton, C., Cottrell, L. Importance of android/gynoid fat ratio in predicting metabolic and cardiovascular disease risk in normal weight as well as overweight and obese children. Journal of Obesity. 2014; 2014:846578.

 

 

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