An important part of your fitness journey is understanding how many calories you actually need to consume to meet your fitness goals. Most people have no idea how much fuel their body actually needs to just stay alive. Conversely, most people drastically overestimate how much they burn from day to day activity and their workouts.
That’s where a test like the MedGem can come in very handy. The MedGem test is described on their parent company’s website as follows:
The MedGem indirect calorimeter, a FDA 510K-cleared Class II medical device, is a state-of-the-art handheld device that accurately measures oxygen consumption (VO2) to determine resting metabolic rate (RMR).
RMR is how many calories your body burns just hanging out. No exercise, no moving, no tweeting or blogging, just lying there doing nothing. For most people RMR makes up approximately 60-75% of the calories burned each day. Surprised at how much you burn doing nothing?
The rest of the calories burned each day are from activity and exercise. Here’s a reality check: Exercising and moving around the office make up only 10-30 % of your daily calorie needs. (TEF or Thermic Effect of Food also makes up about 10%). Therefore, that 30 minute Zumba class does not burn enough to justify an extra slice of pizza or scoop of ice cream. Sorry.
I thought it would be fun to take the MedGem test myself. I recently learned that my local Hy-Vee offers the test for a very affordable $45. I made an appointment with Registered Dietitian Kristen White to get the scoop on my own metabolism.
The test starts with a 4 hour fast and no caffeine. I am used to fasting before early morning labs but that doesn’t mean I like it. I packed my breakfast to eat immediately after and made a promise to myself to hit Starbucks for a Zen green tea afterwards. I was also instructed not to exercise prior. No problem there. But somehow I missed the part about not showering. A hot shower will dehydrate you, I was told, and affect the test. But all the water I drank (trying to make up for the lack of food and tea) probably negated the effects and Kristen assured me it would be fine.
Kristen instructed me how to use the nose clamps and how to place the mouth piece. All I had to do was breath normally and check my tweets for 10 minutes while the MedGem measured my carbon monoxide out put. Once the timer went off, Kristen asked me some questions about my activity level, checked my weight and entered all the data into the MedGem software. In a short time I had my numbers:
- RMR: 1150 calories per day. This is very close to the number I had previously calculated for myself using the Harris Benedict formula.
- TEE (Total Energy Expenditure): With a moderately active job and working out about 5 hours a week I burn on average 1866 calories per day. That means I get to eat that much food per day to maintain my weight. That’s a whole lot of food when you eat whole foods. Also very close to my Harris Benedict formula numbers.
I was really pleased with the ease of the test and the experience. Kristen also gave me a pretty awesome 4 page handout that further analyzed what my nutrition plan should be based on the USDA Nutritional Guidelines. Want to see how my normal daily diet compares? Then check out part two on Thursday!