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From Florissant, Missouri, USA:

I am 24 years old. I am a type 1 diabetic who was diagnosed a little over a year ago. Since then I have been keeping my sugars in good control (70-100 mg/dl most of the time; an occasional 166 or 250 rarely pops up). This year I resolved to gain some muscle mass and am working out with a regimen of exercise bike (a really cool one with a heart monitor) 20-25 minutes followed by intensive weight training. I try to keep my heart rate between 137 and 150 on the bike, which I understand is fat burning metabolism. When I started I was 158 with 16% body fat, now 5 months later I am 161 with 31% body fat. I have gained no muscle, I have lost it according to the infrared device they check your body fat percentage with at the club.

I felt like I was doing good. I have a healthy diet but obviously I am worse off. What am I doing wrong?


I do not believe you are doing anything wrong. You mentioned that your percent body fat was measured with an infrared device. Near-infrared Interactance (NIR) is a relatively new field method to estimate body composition. Compared to skinfold (SKF) and bioelectrical Impedance (BIA) methods, which have been validated and refined through years of research, (NIR) is still in the developmental stages.

The Futrex-1000 and the Futrex-5000 analyzer estimates percent body fat from optical density measured at only one site, usually the bicep. The near-infrared interactance (NIR) analyzer indirectly measures the tissue composition (fat and water) at this site. To date, much skepticism surrounds the use of this instrument and the manufacturer's (NIR) equation to estimate body fatness. Much more research is needed to substantiate the validity, accuracy and applicability of the (NIR) method for body composition assessment.

You may want to look into two other methods as I mentioned above:

  1. Skinfold measurements (SKF) which indirectly measures the thickness of subcutaneous adipose tissue. The SKF is a good measure of subcutaneous adipose tissue and can be used to estimate total body fatness. The SKF is inversely related to total body density and directly related to percent body fat. Population specific equations are based on a linear model and are applicable only to individuals from a specific population subgroup (i.e., equations for children, Hispanics, Japanese natives, white males, white female, obese individuals). A major source of measurement error for this method is the technician's skill in locating and measuring the skinfold site. Make sure that the technician is a skilled individual.

  2. Bioelectrical Impedance (BIA) is a rapid, noninvasive, and non-intrusive method for measuring body composition. Impedance to current flow through the body is directly related to the square of the individual's height and indirectly related to cross-sectional area. Free fat mass (muscle) with its water and electrolytes, is a good conductor of electrical current. Fat is a poor conductor. BIA equations can be used to estimate fat free mass (muscle) and total body water. There are population specific equations and are applicable only to individuals from a specific group (i.e., children, elderly, obese). Eating, drinking, dehydration and exercise may affect bioimpedance measures. Make sure you follow guidelines that are given to you by the individual who is administering the test measure.

Try one of the above methods I have included in my response. I think you may find that you will get much more reliable results from either SKF or BIA.


Original posting 26 Aug 1998
Posted to Exercise and Sports


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