Considering Body Composition

Doctor Nadia considers BMI and Body Composition

Wondering about the difference between the two? Read on.

BMI BMI (Body Mass Index) is a classification based on height and weight (kg/m²). It’s not an accurate determination of body fat, as it can overestimate body fat in athletes and others with a higher lean body mass. It can also underestimate body fat in older people or people who have lost muscle mass (cachexia), because it ignores important factors such as muscle mass, age and fat distribution. Although this limits its overall accuracy, BMI is generally considered a simple and useful measure clinically.

Figure 1: BMI (Body Mass Index) (http://www.lifestyleat.com/body-mass-index-bmi-body-mass-index-to-define-your-obesity-level/)

Body Composition

Dexa Scans A Dexa Scan (aka Dual Energy X-ray Absorptiometry) is a form of x-ray technology and today’s gold standard for determining total body composition. This total body scan determines the three major body composition components:

1. Body fat mass 2. Lean mass 3. Bone mineral content

Dexa Scans give you a total analysis including age, gender, fat percentage, percentile, total mass, fat mass, BMC (Bone Mineral Content) and Fat-Free (or lean) mass. The Percentile for Body Fat is plotted based on percentage of body fat (total) versus age. Fat distribution is determined and it’s important for determining health and risk. For example, determining Android fat (aka visceral/organ fat) vs Gynoid (aka subcutaneous fat around hips, thigh and buttocks).

A Dexa scan analysis may or may not be available in your area, and range in price depending on where you live and which company you use. Generally, they cost anywhere from $100 to $200 per scan and it might not be covered by your health care insurance.

What I have learned from working with so many people over the years is that the scale doesn't always tell us the whole story (I mentioned this in the Blog regarding NSV -Non Scale Victories). Our body composition (Percentage of body fat vs lean) is infinitely more important than the number on the scale. From a health perspective you can learn in the explanation above why body composition is so much more relevant than weight. Sometimes, you may not lose any weight, yet you are burning fat and building muscle, which is really what we want. Our body composition is changing and we can see this in our clothing, but we give the scale so much more importance. Why? Maybe lack of information.

Figure 2 and 3 : Dexa Scan (Dual Energy X-ray Absorptiometry), 1 year comparison on IF/LC

source: IDM clinical files, 2018

Looking at the figure above, you can see how much this person achieved with Low Carb and IF over the course of one year. A picture speaks a thousand words, doesn't it??? She did lose weight (a lot of weight, in fact), but she built muscle and burned fat (and even increased her bone density). Imagine if she had given up because some weeks the scale didn't move???