- "A Lesson in Body Fat Testing"
- "An Even Better Equation for Determining your Metabolic Rate"
- "Is Weight Training Safe?"



Q: "I've often had my body fat tested. Sometimes the trainer has used calipers, and other times used something called a BIA machine. What method is more accurate? Is there anything else that I can have done?"


You can trust the caliper method (when performed by an experienced trainer) and a machine called a DEXA (Dual Energy X-ray Absorptiometry). The Tanita and BIA (Bioelectrical Impedance Analysis) scales are less accurate. According to lecture notes collected from Dr. Mark Tarnopolsky of McMaster University, even he agrees that visual observation is better than using a BIA.

You know something is not right when a "contest-ready" bodybuilder is measured at 16% body fat by the BIA machine! In fact, CB ATHLETICS has yet to record a reading of less than 10% when using the BIA machine, even though a "top-of-the-line" BIA machine was used. Certainly you would expect a lot more accuracy from this model! You don't expect 16% body fat readings when the subjects included competitive bodybuilders and lean 18-year old junior hockey players.

If you have a good trainer available, they should be able to reasonably estimate your % body fat just by looking at your uncovered midsection. If not, a quick skinfold test (combined with a good predictive equation) will give you a decent estimate. One sign of a good trainer is that this won't cost you a cent.


Q: "How does a BIA machine determine your body fat?"


The BIA machine sends an electric current through the body. Fat provides a greater impedance to the current than muscle (BIA = Bioelectrical Impedence Analysis). The impedance value is then compared to normative values from a large data pool, and your body fat is estimated. NOTE: If you enter a different age, gender, or height, you will get a different answer!

These machines estimate body fat percentages using "Regression equations". The machine takes into account your age, weight, height, and "impedance value", and puts all of that information into a mathematically derived equation to help predict your body fat. A regression equation is based on a large amount of data. In this case, researchers have determined % body fat for people of all ages and gender, and then reduced the data to a predictive equation.

Therefore, when you change a variable such as your age, the machine expects a different "body composition" based on "normal" values. This will result in the regression equation giving you different values. You will get a difference no matter what variable you change. For example, if a male enters his statistics and then inputs female as the gender, the % fat will increase. Add height to your input and your body fat will decrease. Inflate your age and % fat will increase.

The regression equation is also the downfall for testing very muscular individuals (i.e. athletes). The values are terrible because athletes don't fit the "normal" data. Once again though, body fat estimation with the calipers are superior (when good calipers used by an experienced trainer).


Q: "Where can I get a DEXA performed?"

Of the other methods currently available, the most accurate method is the DEXA. Unfortunately, your chances of getting one are slim, unless you volunteer for some kind of study at your local hospital. Outside of research, the waiting list in Canada for a DEXA is several months long for females seeking a bone-scan to identify osteoporosis. Many researchers must schedule DEXA scans outside of 9-to-5 hours in order to have access to the machine. Of course, this test costs up to $300!


Q: "So what method should I use to determine my body fat after using the GET LEAN program?"


Provided you use the same method for a follow-up test, any method will be reliable. That is, it will provide an estimate of how your body changed in response to the fat loss program you have been following for a given length of time.



After the last issue, Dr. Digby Sale, Kinesiology Professor at McMaster University wrote in with this more accurate equation of energy expenditure. The advantage of this equation is that it takes fat mass into account and thus more accurately estimates energy requirements in overweight individuals. Accounting for fat mass can help an overweight individual scrupulously design the correct nutritional and exercise program for fat loss.


To estimate resting daily energy expenditure (RDEE) the following equation can be used:

RDEE = 370 + (21.6 x FFM)

FFM = Fat-free mass

(Fat free mass must be expressed in kg)

(For conversion: 1 kg = 2.2 lbs.)


Example: For a male weighing 90.9 kg (200 lbs.) with 21% body fat.

FFM = 90.9 -(90.9 x 21%)

FFM = 90.9 - 19.2

FFM = 71.7 kg

RDEE = 370 + (21.6 x 71.7)

RDEE = 1919 kcal

Therefore, a 200 lbs. individual with 21% body fat will have a resting daily energy expenditure of 1919 kcal.

In contrast, had the same individual used a more general equation, the result would have overestimated the caloric needs of the individual. Using an inaccurate number may impair body fat loss because calorie intake will remain at weight maintenance levels. For example, some trainers recommend using Bodyweight (lbs.) x 11 to estimate RDEE. Using this equation, you will get:

RDEE = 200 x 11

RDEE = 2200 kcal

Even that is only a difference of just under 300 kcal this overestimation of calorie needs can severely hamper the fat loss efforts of many individuals. Furthermore, a recent study suggests that lean and obese women significantly underestimate their daily energy intake (Weber et al., 2001). Lean women under-reported total energy intake (TEI) by 23-30% and obese women under-reported TEI by ~39%. Inflated calorie requirements and excess calorie consumption are two strikes against a successful fat loss program. More accurate food monitoring is a simple step in the prevention of obesity.

According to Dr. Sale, the reason FFM is used to calculate RDEE is that fat is so biologically "inert" that it can be ignored. That is, fat does not burn energy at rest, while muscle does. Muscle contributes a significant portion (20-25%) of the RDEE. If the male in the above example increased his FFM to 76 kg with a weight training program, his RDEE would increase to 2012 kcal, a 5% increase in metabolism! Score another one for weight training as a method to help lose body fat. In contrast, changes in body fat have virtually no effect on RDEE.

Dr. Sale also provides an example of the metabolic power of muscle using the estimate that muscle represents 50% of total body mass. This is a reasonable estimate for healthy young males with "normal" body composition (~10-15% body fat). For females and obese individuals, the percentage of total body mass that is muscle would be lower because of their higher % body fat.

In our example, muscle mass would be ~45 kg in a 90 kg male.

Muscle mass = 90.9 x 0.5

= 45.45 kg


In ISSUE #78, it was estimated that muscle contributes 25% to total RDEE. Therefore, muscle mass would contribute 480 kcal to the man's daily energy expenditure.

RDEE = 1919 x 0.25

= 480 kcal

This works out to 9.6 kcal/kg muscle/day (4.4 kcal/lb). This is a far cry (one-tenth!) from the estimate that each pound of muscle burns 50 kcal. Chalk that up as another health and fitness myth.

The "resting" metabolic rate of muscle can be transiently elevated after exercise. This is particularly true after high intensity exercise, including resistance exercise. Carrying extra fat increases energy expenditure during load-bearing activities, but this occurs due to increased requirement of muscle work, not due to an increase in fat tissue energy expenditure. Dr. Sale concludes, "the best way to increase resting energy expenditure is to increase muscle mass and perform regular intense exercise".



The RDEE calculation was taken from McArdle, Katch, and Katch's exercise physiology textbook (4th edition, 1996, page 154) where they cited:

Cunningham, J.J. Body composition and resting metabolic rate: the myth of feminine

metabolism. Am. J. Clin. Nutr. 36: 721, 1982.

Weber, J., et al. Validity of self-reported energy intake in lean and obese young women,

using two nutrient databases, compared with total energy expenditure assessed by

doubly labeled water. Eur. J. Clin. Nutr. 55: 940-950, 2001.



Q: "Sometimes when I do heavy leg presses I end up having to cut my workout short due to headaches. Other times, I develop a headache after training that persists for hours. What's going on?"


Exertion headaches are very common during exercises such as the leg press. In fact, in CB ATHLETIC research conducted at McMaster, a male subject dropped out of the study because his doctor diagnosed him with exertion headaches (due to the intense leg press exercise protocol). It's not surprising though, considering McMaster professors Dr. Digby Sale and Dr. Duncan MacDougall had previously shown increases in systolic blood pressure of up to 350-400 mmHg during heavy leg press exercise (NOTE: resting systolic blood pressure is only 120mmHg!).

For people that suffer from exertion headaches, they should first consult their doctor to determine if there are any additional concerns. Barring other problems, the lifter should reduce the intensity and volume of the exercises that lead to headaches, or remove them completely from training. There is little reason to push to the onset of headaches. Simply find a substitute exercise for the leg press.

Furthermore, after pushing yourself that hard on the leg press, take your time returning to the standing position. Your blood pressure will rapidly decrease to normal and the movement of blood away from the head (as you stand) could lead to dizziness and fainting. This is definitely not something you want to occur in the weight room when you are surrounded by iron and other lifters.


Q: Wow. Based on that response, is weight training considered dangerous?


While controversial, the answer to that question is, "no". Relatively, weight training is not dangerous, as the injury rate is much lower than that in other common sports such as hockey, football, or even soccer. However, it is possible to be injured while lifting weights, but one must understand that these injuries are most often due to improper technique or poor equipment.

For example, a close friend recently dislocated his shoulder while training. It was a serious injury and it set him back nearly a year of progress, which was very frustrating because he was making great gains up to that time. Most importantly, it didn't have to happen. After all, he trains with proper technique (not perfect, but well enough that no injury should occur) and he was using a familiar exercise. Unfortunately, he just didn't take into account the limitations of the equipment.

Here's how it happened: He completed a set of incline bench presses and was attempting to rack the weight when he overestimated the distance to the rack. His arm extending back under a heavy load, thus dislocating his shoulder. First off, this is evidence that supports the recommendation that everyone should always train with a spotter. Second, this situation suggests that you should become very familiar with the set-up you are about to use.

Ask yourself a few questions before you begin your next workout. Is your equipment going to be your downfall, despite your perfect technique? Is there any safety mechanism that will prevent the weight from falling on top of you in the case of a missed lift? Is the equipment stable and well taken care of? Get familiar with your gym and always use a spotter for heavy or fatiguing lifts!

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