Calculating calorie needs

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Dietitians are known for being able to determine a person’s calorie needs. It’s a huge part of our job. If calories didn’t matter, then we wouldn’t be facing the current obesity epidemic in our country. So, have you ever wondered how those of us in the profession figure out how many calories you need? Well, you’re in luck!

Do a search on the Internet about how to determine your personal calorie level and you’ll come across pages of helpful information. There’s everything from fill-in-the-blank forms to worksheets you print out and fill out on your own.

Personally, I use one of two equations. The first is known as the Harris Benedict Equation (HBE), which has been proven over time to provide a fairly accurate measurement of a person’s basal energy expenditure (BEE). The second is the Mifflin-St. Jeor Equation. Both take into consideration your age, height and current weight.

BEE represents the number of calories that you need to meet your minimum calorie needs to keep your body running at its most basic level. And since most of us aren’t comatose, they both use activity factors to account for getting out of bed and moving around, exercise and illness.

There are more simple ways of calculating calorie needs based solely on a person’s weight. For example, I will use 25 calories per kilogram of actual weight to get a baseline weight loss calorie need, 30 calories/kg for weight maintenance and 35 calories/kg for weight gain.

These are quick and dirty ways to avoid long calculations, but they aren’t always the most reliable. Certain conditions such as exercise level, percentage of overweight and chronic health conditions can make these easier calculations less exact.

In general, most methods of estimating calorie needs are going to be in the ballpark, but there are always instances that will be exceptions. If a person is very muscular and has a very high amount of lean body mass, the usual calculations tend to be less accurate and can be less than the person’s actual needs. The opposite is usually difficult as well. The more body fat, the more adjustments need to be made to get the best picture of the actual number of calories needed to maintain or even lose weight. Then there are conditions such as cancer and pulmonary diseases that pose their own challenges.

For the past 15 years, I have had the opportunity to use an indirect calorimeter to measure personal calorie needs. This instrument measures the volume of oxygen that is consumed over a ten minute period, giving a very accurate measurement of anyone’s personal calorie needs. Although this method is a bit more involved than using a calculator,

I am very excited when I help someone find their calorie needs using this method. For someone who has been struggling with their weight, up or down, this can be a very important key to unlocking the mystery and achieving their goal weight.

Mary Koch is a Registered Dietitian at Banner Churchill Community Hospital, VA Lahontan Valley Outpatient Clinic and consultant for Pershing General Hospital. Send your nutrition questions to Mary at


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