Bod Pod Experience

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Bod Pod at Cal State Long Beach

Take me to your leader!

Something that I’ve wanted to do for a while was get a body composition analysis done. A body composition analysis tells you what percentage of your body is lean body weight and what percentage is body fat. When people talk about weight loss, it’s fat loss they’re talking about. One of the reason why trying to measure body composition progress via a scale can be frustrating is that one may lose body fat, but demonstrate no weight loss because that the loss in body fat mass is offset by gains in muscle mass. Hence the recommendation that you should also measure yourself with a tape measure. While 5 lbs of fat weighs as much as 5 lbs of muscle, muscle is far more dense, therefore it takes up less space. (See photo here)

There are several ways that body fat is “measured.”

The Best Methods

The gold standard is hydrostatic testing, where you’re weighed on dry land and then lowered into a big tank of water with as much of the air expelled from the lungs as possible to measure how much water is displaced. The procedure is repeated three times and amount of water displaced is averaged. There’s a formula that used to calculate the percentage of body fat and lean body mass using weight and water displacement because fat and muscle displaces a specific amount of water. This procedure is the most accurate (and the standard by which all other assessments are measured against). It is, however, very labor intensive.

Another good method is the dual energy X-ray absorptiometry (DEXA). DEXA takes an x-ray of your body using two different types of energies. Fat absorbs more of one of the energies, so there are two different images created. A computer subtracts the two images to reveal the amount of fat relative to muscle. From this information overall body composition can be calculated. It is often quite expensive.

A relatively newer method is the Bod Pod, or more scientifically Whole-Body Air Displacement Plethysmography, which uses a similar procedure hydrostatic testing. Instead of displacing water, air is displaced. Height and weight are measured. You’re placed in a little pod-like chamber. The amount of air displaced is measured. The amount of air held in your lungs is measured as well. Then using a very similar formula to the one used for hydrostatic testing, overall body composition is calculated. A study found that the BodPod is valid (it measures what it purports to measure) and reliable (the measurements are consistent across time). The BodPod is a great alternative to hydrostatic testing because it’s easier for participants and is less hassle. Also, it is often cheaper than the other two previously mentioned methods.

Less Reliable Methods

Body fat calipers measure body fat by measuring skinfold at various parts of the body. This method can be as reliable as the above methods if done by a trained and knowledgeable professional. Otherwise, measurements are not reliable because there is too much variability from person to person doing the measuring and from time of day.

Body fat scales measure body fat by measuring bioelectrical impedance. Fat holds more water; therefore, it conducts electricity more easily than muscle. There are two main types. One looks like a regular bathroom scale and the other looks like a handheld game controller. These scales are often quite inaccurate because too many factors (e.g., state of hydration, time of day, quality of product) affect the reliability of the readings. In my opinion, these scales are useful for gathering trends, but not for actual readings.

Measurement method (e.g., US Navy body fat calculator) measures body fat with a tape measure by measuring the circumference of different body parts. NerdFitness reports that this measure can be inaccurate because it only takes a few data points. I also imagine that is one is highly muscular, this method will overestimate body fat.

My Bod Pod Experience

For a long time I wanted an official assessment of my overall body composition. I did a lot of research on the different methods and based upon the information I read, I decided that the best method on ease, accuracy, and price was the Bod Pod. I looked for places where I could get access to a Bod Pod in NYC. Although different institutions have a Bod Pod, it didn’t seem as if it was accessible to the public. Brooklyn College had one at one point and offered its service for $75, but it got shut down a few years ago.

Before I left for LA, it suddenly struck me that I should look to see if I could find Bod Pod service in Long Beach, CA. I googled and the LifeFit Center at Cal State Long Beach popped up. Not only was it only 15 minutes away from my parents’ home, it was also only $50. I realize now that travel is a great opportunity to get services that are cheaper than what you would find at home. I scheduled an appointment for this morning at 8:30. I was instructed to wear a swimsuit, eat a light meal the night before, no exercise 4 hours before, and no food and water for at least a couple of hours before the appointment.

Ben came with me to observe the process. We parked by University Parking where there was metered parking and it was also close to the LifeFit Center. It was $1 for a half hour. Each appointment is scheduled to last a half hour, so we waited as close to my appointment time as possible before putting money in the meter. Ben was prepared to run out and put more money in if we ran late.

The process was very easy. The technician, Joe, explained the the machine and what was happening at each step. My weight and height were measured. Then he handed a swim cap to me (to minimize the air trapped by my hair) and I sat inside the Bod Pod. I was instructed to relax and not move while air displacement was being measured. Ben took tons of pictures of me in the Bod Pod. I had to focus hard not to move because all I really wanted to do was wave my hands around while Ben took the photos. I didn’t feel claustrophobic at all inside the Bod Pod. There was a fair amount of room in the pod and a nice big window where I see easily see out. Joe opened and closed the door of the pod several times, so I never felt like I was locked up inside the pod.

20140114-102337.jpgJoe measured the amount of air displaced three times (which was then averaged). The next phase was measuring the amount of air in my lungs. I placed a nose clip on my face and then I had to breathe through a tube in my mouth. When he gave me a signal, I had to give three quick huffs.

And it was over. He let me out and remarked, “You’re one of the few people who did it on the first try.” Apparently a lot of people huff too strongly, so they need to redo it.

The whole process took 15 minutes. The computer calculated my body composition and Joe handed the piece of paper over to me. Before I came to the session, I estimated that I would be somewhere between 22-23% body fat. I knew there was a chance that the number given to me by the Bod Pod would be higher than what I thought I would be. I was fine with this. A number does not define who I am. It does not measure my self worth. I’m assessing my percentage of body fat and lean muscle mass for my own information and curiosity. I looked at the paper and the number I saw blew me away.

17.3% body fat

I totally did not expect this. I am much leaner than I thought I was.

I’m really pleased, not because of the low number, but because my focus on improving running and weightlifting had such a profound impact on my body. When I first met Ben two years ago, I weighed 138.8 lbs and I had just (re-)started an exercise program. I had gotten out of shape and I wanted to be healthier and fitter. Rather than focusing on losing weight (and losing weight at a rate of 1 lb a week, which is often the recommended rate), I trained to become stronger and faster. I wanted to lift more weight. I wanted to run faster.

By focusing on performance related goals and eating more moderately sized portions and cutting back a bit on indulgences, weight slowly came off me. And I do mean slowly. Between Jan 2012 and now, I’ve lost approximately 12 lbs. Twelve pounds over two years is six pounds a year, half a pound a month, two oz a week. Two ounces don’t show on a scale. Half a pound a month in it of itself can seem like nothing. But all of these small losses add up and lead to a significant change over a long period of time.

The number does not define me, but it does reflect the changes that I’ve made in my life.

Does the experience with the Bod Pod change anything in my life?

Actually no. I like having the number because I like information and quantifying things, but I will continue to do what I’ve been doing. I’ll train to become stronger and faster. And I’ll blog to record this journey and the life I’m living.

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8 thoughts on “Bod Pod Experience

  1. I’ve always wondered about this kind of stuff. I had my body fat % done years ago with calipers, but I don’t even remember what it was. I’d probably be terrified to know what I am now! But you’re right about small changes adding up over time. I used to be a pop drinker as a teenager. In college, I cut it out completely in an effort to be healthier. Over the course of one year, I lost 15 lbs without doing anything other than not drinking 2 cans of pop a day. The change happened so slowly that I literally woke up one day and realized that none of my clothes fit! I still don’t drink pop, except for the odd root beer here or there.

    • Yeah, soda (I’m from the West Coast, so it’s soda to me) is the worst when it comes to weight gain. I used to work on a floor that had a vending machine down the hall, so it was really easy and tempting to get a can each day. I did that for a while and gained weight really quickly. I got alarmed and stopped drinking a can a day and just as quickly the weight went away.

      Hot chocolate was another source of downfall for me. I don’t want to talk about I looked like in the spring one year after spending a winter of drinking two mugs of hot chocolate per day.

  2. Oooh, yeah. We have a Bod Pod at our school in the kinesiology lab (for which I am a student). Though we don’t get to use this during our lab sessions (because it’s more expensive), we do get to use the hydrostatic weighing tank at the end of the year.
    Very cool that you got to try it out, and you’re right. The number doesn’t define you (but great job on the healthy weight loss anyways :D).

  3. Pingback: Drop Some Knowledge #7: Measuring Body Fat Percentage | blessed with thunder thighs

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