We live in an age where information is at our fingertips. When it comes to deciphering how many calories we need to eat, it’s as simple as plugging in some numbers into a website calculator and within seconds we know the answer! In this article, I’ll share my experience getting my metabolism tested in a lab and why using an online calorie calculator could be hindering your weight loss efforts. We’ll discuss how eating based on your metabolism gets results!
The Calorie Calculators
Most website calorie calculators use the Harris-Benedict equation behind the scenes to determine your caloric needs. You enter your gender, weight, height, and age and are given a number. The formula is below.
Calculate your BMR (basal metabolic rate):
- Women: BMR = 655 + ( 4.35 x weight in pounds ) + ( 4.7 x height in inches ) – ( 4.7 x age in years )
- Men: BMR = 66 + ( 6.23 x weight in pounds ) + ( 12.7 x height in inches ) – ( 6.8 x age in years )
This is usually the best case scenario for determining your caloric needs. The number that you get from this equation represents your basic metabolism: the number of calories your body needs to sustain life such as keeping your heart beating, breathing, brain functioning. You can factor in your activity level as well.
BUT….what this formula does not account for is the amount of lean body mass you have. So you can’t accurately determine your protein needs based on this calculation. Your muscles are a calorie burning powerhouse and should be accounted for! The only natural way to increase your metabolism is increasing your muscle mass and you can’t do that with inadequate protein.
The formula also does not account for hormonal status. Hormones are a major influencer of weight loss. And if you have a thyroid condition, using the calorie calculators can be off as much as 25%. That could spell major frustration at not losing any weight.
According to the Harris-Benedict equation, my BMR is 1,657. So ladies, keep in mind that the random recommendation of eating 1,200 calories a day to lose weight is not applicable to everyone! If I did that, I would literally be starving myself, would never lose weight and would never get toned muscles.
Laboratory Metabolism Testing
So how do you address this missing link? Enter the metabolism test. I went to the George Washington University Weight Management and Human Performance Lab and had two tests done to determine my metabolism and caloric needs. The first was a scan using an X-ray to determine my body composition and bone density. I laid on a table for about 5 minutes while a machine moved over my body one segment at a time.
The body composition results are really interesting! It tells you your percentage of fat, exactly how many pounds of fat you have on your body, exactly how many pounds of muscle you have, how much your bones weigh, and how much of the really unhealthy fat you have surrounding your organs.
The good news is that my bone density is excellent. The surprising news is that I have just under 6 pounds of bone mass. That’s it! Of my total body weight, only 6 pounds are from my bones. I was so surprised upon hearing this news that I had to ask if that was normal. And yes, females have normal bone mass between 5-6lbs. Fascinating! Our bones are so light, but so strong.
For the second test, I wore a mask and breathed into it for about 12 minutes. It measures the oxygen and CO2 that I expire to determine my resting metabolic rate. My RMR according to the test is 1,823. Among the cool things the respiration test reveals is how your body is burning energy. It says what percentage fat you’re burning and what percentage of carbs you’re burning. (You should never be burning protein, aka muscle wasting.) Right now, my body is burning more fat than it should. That sounds good…but my body is burning dietary fat, not stored fat.
Metabolism Testing at GWU’ s lab
“When a person is burning a large percentage of calories from fat, it typically means that 1) they’re eating a diet that is too high in fat, and as a result, they’re burning dietary fat for fuel instead of stored bodyfat, or 2) that they’re eating too low carb and the body increases it’s reliance on bodyfat for fuel. The second situation intuitively seems like what you’d want, however, eating too low carb typically means that some of the protein you eat is going to be converted to carb, and then you don’t have enough protein to support muscle growth, which results in stunting of muscle growth and a slowing of the metabolic rate,” says Dr. Todd Miller, the Director of the lab.
The Plan
After the tests, I met with both Dr. Miller and Stephanie Mull, a registered dietitian. We discussed the results and strategies to optimize my nutrition to support both my metabolism and weight loss. My particular plan includes more strength training, more protein, and less sweets. (Damn my sweet tooth!) The goal of the program is to increase the calories I burn by increasing my RMR.
If you’re in the Northern Virginia area, I highly recommend making an appointment at the GWU lab on their Ashburn campus to get your metabolism tested. It truly is the most accurate way to determine your specific calorie needs. We are lucky to have such a fantastic resource close by!
[For further reading on the subject, Precision Nutrition wrote a fabulous article explaining why counting calories isn’t the best approach to weight loss and their suggestions for eating to support your metabolism.]
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