I’m sure you’re all aware of metabolic calculators – they’re all over the Internet. With these calculators, you input your height, weight, age, and gender and they purportedly tell you how many calories you can eat to maintain your weight. From there, you can theoretically figure – supposedly with great scientific precision – how many calories you need to cut to lose weight. One of the best known examples of a metabolic calculator is the Harris-Benedict formula. We even have a Daily Calorie Needs Calculator here at 3FC.

Some people swear by the accuracy of metabolic calculators and say that they get great results from them. But not me – the ones I’ve tried have been off by up to 50% of what my real life experiences (four years of tracking my calories in Fitday) teach me. And I’ve often wondered why? Am I some kind of freak -- completely out of the norm? Or could it have something to do with my large weight loss?

Well, I came across some interesting info about metabolic calculators this morning while taking a continuing education course about metabolism and weight loss that’s worth passing along. Part of the course analyzed the Harris-Benedict formula (and others) and discussed its flaws and why it’s not reliable for many people.

Here’s the history behind the HB formula: it’s based on a 1919 study done on 239 individuals – 136 males (average weight=142 /average BMI=21.7) and 103 females (average weight=124/average BMI=21.5). It’s no surprise that 86 years later, average BMIs are far higher among the general population: in 2002, the average weight of a woman was 164 and her BMI was 28. So the study is old (86 year-old studies are prehistoric in science) and it’s based on a small group with characteristics quite different than today’s general population.

The course went on to say that, perhaps as a result of these changes in the characteristics of the general population since 1919, the results obtained from using the HB formula today aren’t accurate for a significant number of people. It said that the HB formula is accurate (with a margin of error of +/- 10%) for only 69% of the non-obese population and 64% of the obese population. ("Mean Body Weight, Height, and Body Mass Index (BMI) 1960-2002: United States,” prepared by CDC’s National Center for Health Statistics) In other words, the HB formula isn’t even within 10% of predicting the calorie needs for approximately 1/3 of the population.

Well, heck! Maybe I’m not a freak after all ( … or maybe I still am! ) I feel better knowing that there are a substantial number of other people who aren’t getting correct, real world information from metabolic calculators either. Which is not to say that metabolic calculators aren’t a source of valuable information or a good place to start – it’s just that they’re not the final answer to the calorie puzzle. I think that only can come from personal experience – tracking portions and calories over time and seeing what works for each of us as individuals.

And that's how I'm spending my Sunday morning!

>>" think that only can come from personal experience – tracking portions and calories over time and seeing what works for each of us as individuals.<<"

I was just setting up my food for the day, and entering on FITDAY. Just before I read this, I thought about how I had eye-balled my measurements and when I did measure, the tablespoons were "heaping," or the half cups "just a little over." A year ago and subsequent, I thought I knew enough and all the how-to's to maintain the weight I was at, even though I hadn't reached my final goal. The result was that I was only cheating myself by not using Fitday and exact measurements, and I've packed 20# back on to prove it. For me, Fitday and EXACT measurements are the only way I can possibly be successful. From past experience, I know this is what works for me.

Keep sharing that knowledge, Meg. I for one NEED IT!

Best!

dip

I'm glad this topic came up today. Sunday (if I'm off work) is my evaluation day. My fitday stuff is just NOT jiving with what is really happening. According to my numbers there, I should be losing about 1 lb or a little over per week. I lost 2 the first week and 2.5 this week.
This morning I tried this site http://www.hussman.org/fitness/bmrcalc.htm and I'm not sure I'm any smarter.

I wonder if I'm falling into an inverse #1 problem with calorie counting. You know how they say most folks under estimate their intake and over estimate their expenditure? Maybe I'm being over cautious. It is conceiveable that I have a more active lifestyle that I give myself credit for.

But the problem really seems to be my 'detail-itis'. When I first started losing weight, my statistics were just about right on. If I lost one pound, I could go to fitday and find the appropriate about 500 calories deficit.

I should be happy that I'm getting closer to those size 4 jeans, shouldn't I? Instead I want calculators and things to jive. I'm spending my Sunday morning trying to make sense of this.

You may or may not be a freak, Meg. But I'm definitely a control freak

I have a cookbook from way back when that gave the formula of multiplying your weight by 13. It has always worked for me. Even as I lose weight I have been able to recalculate with this formula based on my current weight and continue to see results. The calorie count it gives me is always very close to that of the calculators.

With that said, I don't put a lot of stock in any of the calculators or formulas. I think I just got lucky and happen to have stumbled across something early on that works for me. I've always used them to establish a starting point and had the expectation of adjusting things on my own as needed. As it turns out, I've never really needed to make any major adjustments.

I am painfully average when it comes to my weight loss goals, though. I exercise and push myself but I don't do it every day. I've always incorporated weights into my exercise routine but I certainly don't do anything near what would be considered weight lifting. I strive to maintain a healthy body fat percentage but don't have any desire to ever have it in the teens. I eat healthily but I wouldn't describe my diet as "clean." So, I don't know that there is necessarily a connection for everyone but my experience has been that the less lofty my goals the more likely these basic calculations are to apply.

I am still relatively young and haven't spent a lifetime being overweight (although I've thought I was "fat" since I was in the 6th grade LOL). I was never a serious athlete but I was certainly active from a very early age. I don't believe I've done any long term damage to my metabolism or anything like that. As long as I stay active I can pretty much maintain my weight on about 2000-2300 calories each day. I can lose weight in the 1500-1800 range. But again, my ideals aren't anywhere near a lot of people's.

I think we are each a puzzle and have to choose and put our pieces together in a way that is unique to our own needs and goals. I try hard to keep the attitude that it doesn't really matter what works for anyone else. If something doesn't work for me then it is completely irrelevant. Had multiplying my weight by 13 not worked for me in the beginning I would have had to try something else. Which I suppose is the point. For all of the scientific studies and statistics there is still no guarantee that all of it is going to apply to me - or any of it for that matter. In my opinion, the best bet for anyone is to learn as much as possible about nutrition and exercise, choose the bits and pieces of information that make sense and seem applicable, then give them a try. But, the key to success is an open mind and a willingness to keep trying until you find the magical formula that works for you and that you can live with for the rest of your life.

As far as I am concerned, statistics are always tricky (but necessary!) - they can be manipulated so easily to support just about any theory. There are always people who prove the study and always people who seem to disprove it. So, rather than count myself in or out of the masses I consider myself a statistic of one and do whatever works for me regardless of what anyone else says "should" work.

Jawsmom - Bravo for a wonderful post! You summed it all up much better than I ever could.

1919, huh?????

Back before we had labor saving devices such as dishwashers, leaf blowers, vacumn cleaners (I think there were VC's but most people didn't have them), etc.? there WERE washing machines, but they still took a certain amount of manual labor to use...

I believe most Americans were still doing manual farm labor back then, as well - not a lot of 'office jobs' in 1919.

One of my favorite series of children's books - the All of a Kind Family series - takes place between 1912-1919 and is about a Jewish family living in the New York City. (they're excellent books, BTW) Reading the chapters about Monday (wash day) or preparing for the Sabbath evening, it's easy to see why people back then burnt a lot more calories in the course of a day - there wasn't a whole lot of time to sit on your butt, and of course no TV or Internet - the film and radio industries were still in their infancy.

Great post, Meg! Sure sheds a different light on the 'esteemed' Harris-Benedict calculation (and incidentally, they've never worked for ME, either...go figure )

Good points, Karen! It's kinda hard to imagine that the 1919 study subjects' metabolisms were in the same league with those of today's typical drive-thru couch potatoes. I recall reading that the average calories around the turn of the century were higher than today (though sugar intake was far lower) but obesity was almost unheard of due to the higher levels of physical activity. Do you know anything about that? If true, wouldn't that skew the HB numbers higher? (which is my experience with them -- they're all too high -- even though I am NOT a couch potato! )

I wonder why no one's tried to replicate the HB study? (I'm assuming that no one has since everyone is still relying on the 1919 data) Or perhaps the concept of a one-size-fits-all metabolism is just out of date? Certainly everyone here at Maintainers can testify that we're all different!

Ya got that right...

I was coming back to edit my post - if anyone is interested in a good read about the way things have changed as far as housework, go to your library and check out Never Done: A History of American Housework by Susan Strasser - a VERY interesting book to say the least.

From what I've read, doing the household chores (including the twice-weekly bread baking - including kneading) sounds like it was the equivalent of a REALLY hard workout today (anyone see the PBS series "1900 House"?) Even something that we consider mundane today - like taking a hot bath - required LOTS of muscle work: Pumping out buckets of water by hand, chopping the wood for the stove to heat the water, pouring bucket after bucket into the tub, then afterwards having to dump the water out (so as not to waste it, people would use the water in the garden) and clean the tub. (of course by 1919, many folks in cities had plumbing, but there were still plenty of people in rural areas that did not yet have this luxury - as an example, Laura Ingalls Wilder wrote an article in the early 1920's titled "So We Moved the Spring" - relating on how Almanzo and her, after years of toting buckets of water to and from a spring, created their own plumbing from their water source to the farmhouse at Rocky Ridge Farm - I believe it's in the book A Little House Sampler.