When it comes to weight loss, one of the critical parts of the process is monitoring – for you as a weight loss consultant, and for your clients: since what gets measured, gets managed. Most people measure their progress using a scale – but as you know, measuring weight in isolation may not be the best way to track a person’s progress.
Why is measuring total body composition important in preference to total weight loss?
Measuring body composition is important to show more detailed features of a person’s physical state like fat mass and fat free mass (muscle). Tracking body composition gives useful information for a number of purposes:
• To monitor a person’s overall health
• To determine if weight loss interventions have achieved their intended results
• To monitor weight gain – of fat mass, or fat free mass (or both).
What is important in a body composition measurement?
In order for a body composition measurement to be useful, it needs to meet a few critical criteria:
• Accuracy: It’s important that whatever is measured, is measured with accuracy and precision – in order to be useful, the information needs to be correct! The technique also needs to be accurate for a wide range of people.
• Consistent: Over any given period of time, the measurement needs to be reliable – again, to ensure that, over time, tracking changes in body composition can occur.
• Simple to use: Someone with sufficient training should be able to easily apply the measurement technique – since any unnecessary complexity can introduce the risk of measurement error.
In a nutshell, the key is reproducibility – the technique needs to be correct, reliable over time, and easy for people to use.
Not all body composition measurement techniques are the same
As we have alluded to, not all body composition measurement techniques give the same results – which means it is important to understand where those results might vary.
Researchers from the Functional Food Centre at the Oxford Brookes University sought to test air displacement plethysmography (ADP) and bioelectrical impedance (BIA) to compare the techniques with each other, as well as how those different techniques compared with skinfold measurement.
41 participants (in a fasted state, wearing skin-tight swimsuit and swimming cap) were measured using the three techniques (ADP, BIA and skinfold) on two occasions over a 7-day period.
The study tested several aspects:
• Does the test give the same result if administered again on the same day?
• Does the test give the same result if administered again on a day soon after the first test?
• How comparable are the ADP, BIA and skinfold measurement techniques?
Results and conclusions
Analysis of the measurement data found the following results:
• Both ADP and BIA measurements are consistently reproducible on the same day and also over time
• A mean difference of 3.1% was found between ADP and BIA – indicating that although either technique is accurate, it would be better to pick one and stick with it over time (in preference to using the methods interchangeably)
• All three methods – ADP, BIA and skinfold measurement – correlate closely when measuring body fat.
Hillier, S. E., Beck, L., Petropoulou, A., & Clegg, M. E. (2014). A comparison of body composition measurement techniques. Journal of Human Nutrition and Dietetics, 27(6), 626–631.
Do you have a body composition measurement technique you recommend to your clients? What are the benefits and pitfalls, in your view?