Don't let the BMI get ya down...focus on BF%

ambrosij · March 2011

I wanted to write a post today on BMI, and the dangers of focusing too much on the magic "normal" numbers. I will also copy this over to my blog. I wanted to start with a personal story. First, I am in the Army, an Officer in the Army, so obviously being heavy is looked down upon quite a bit. Unfortunately, I have always been one of the heavy guys. At leat twice a year we take a PT test, which is always an easy pass, and we also do a Body fat test, which I have always been a few percentage under what is allowed. The Army has a certain height/weight ratio scale which is closely related to BMI in determining if you need to be "taped," a process wherein your abdomen and neck is taped three times, averaged, computed in with your height and age, and translates into a body fat percentage (it is highly inaccurate, but it is the way the Army does it).

When I was younger, in my teens, I computed on a national level in Nordic Skiing, a highly aerobic sport, and I was in incredibe shape. But, I do believe I abused my body in those years with over training, and really going to the extremes in order to be succesfull and competitive, in fact many of the individuals who I once raced against were in the last two olympics. As my final ski season ended, and I made the decision to go to a college that did not have a ski team, I made a huge decision that eliminated an enormous part of my life, the physical fitness part of it. Without the extreme training, and simply being lazy after years of hardcore working out, I gained weight, and thus began my continous battle with cyclic weight gain and loss. When ski season ended my Senior year of highschool I weighed about 170 pounds, shredded from head to toe without an ounce of fat. By the time I went on to college I had already blown up to 220 pounds. The odd thing was, I looked normal. Unless I was to take my shirt off you wouldnt really notice that I was a bit heavy and not really toned. I could stay up with the "in shape" crowd during our physical fitness workouts and really blended in. But I knew I was heavy, I knew my fat percentage had substancially increased, and according to the BMI I was "Obese."

My sophmore year of college I made the decision to get back to what the charts said was "in normal range" for my BMI. Based on my current weight of 220, my age of 19, and my height of 70" I was obese and my BMI was 32. In order to be in normal range with a BMI of about 22-24 I would need to weight 167 lbs and not an ounce more, in fact I set my goal weight at 160, that equated to a total of 60 pounds, no easy task to say the least. I went back to the basics and began implementing training and diet regimes that had been ingrained into my head in earlier years. In two weeks of intense dieting, supplementation, and working out my weight was already down into the 190's. It took another month and a half to get down into the 180's. I was working out no less than two hours every day, and often 4 hours at least three times per week. Additionally, I was taking many supplements to include protein, creatine, ephedrine (everyone was taking it back then), and some others, I also put myself on a super low calorie diet and aimed to burn at least twice as many calories as I was taking in. My one luxury was a Three musketeers on twice a week, and I didnt diet on Saturdays (I was in college I had to get my party on at sometime). By July I was down to 168 pounds and I was also at a point where people became seriously worried about my apperance. I was often asked if I was sick, my mother was extremely concerned, my friends said I looked like I had an eating disorder. I was happy though, for the first time ever I was able to weigh in and not be taped by the Army, I came in three pounds under what the maximum cut off is before being tapped. Additionally, I was running two miles in just under 12 minutes, and I was gymnist strong in the arms. I was in incredible shape to say the least. For the first time in my adult life I had a six pack, my cheek bones stuck way out and all seemed great. The funny thing was that according to the BMI I was still "marginally overweight." I was disgruntled to say the least, I couldnt believe the chart could be so flawed. I decided to get my body fat percentage done professionally, at that time it was done professionally with calipers. I actually had my Dr. do it and the results were a bit startling. My body fat percentage was barely 3%. I had gone to D.C. for the fourth of July that year and a picture was snapped of me sitting on a curb kind of twisted looking to the right. Every single rib showed through my sides, my face looked scary thin, and I just didnt look "healthy" even know I was fitter (at least by Army and BMI standards) than ever. 3% body fat is not a healthy percentage, elite athletes are generally told to maintain between 5-9% and the average fit male is at about 12-14%. I could not sustain a 3% body fat, and if I did eventually parts of my body would begin to degrade, it is simple fact. I was STILL OVERWEIGHT according to the silly BMI.

As the next couple of years went by I slowly put weight back on, until I graduated at 195 pounds, which was a great weight for me. According to the BMI I was overweight, but come one really? Five years and a couple deployments later I had gained a substancial amount of weight, in fact I was weighing in at 272 pounds. I was taking some very serious supplements, and while I was still passing the PT test, squatting nearly 650 pounds, and benching over 350, I looked very very fat, alot of it was water retention and simple bloat. I was tapped and identified for being over weight. The paperwork cited that I was 94 pounds over the acceptable army weight and 7% over on body fat. I actually thought it was a bit humorous because if I had lost 10% of my weight and it was all fat, I would still weigh in the 240's. I did what I had to do and got back down to 220. For the last three years I have bounced between the 220's and 240's, which according to the BMI is morbidly obese. I have decided to get back down to 200 because it is time for a permanent change and no more bouncing up and down. I almost fell into the "Army weight standard" and BMI trap again, but even at my current age I would have to reduce to 178 pounds, a weight that I am pretty sure would be unhealthy for my body type.

So what is the point of the story? The BMI was developed years ago by a Dr. that thought he could simplify body types and weight ranges into an easy to understand scale, in fact just the opposite has happened. I have no hard research but I would have to guess that at least 50% of the population is like me and simply can not fall into that scale without serious muscle atrophy and very dangerous weight loss tactics. So next time you punch your numbers into that BMI calculator take it with a grain of salt, it means nothing. Get yourself a device that will measure body fat (not the cheap innaccurate scales), even better get hydro tested (where they drop you in a bucket of water and measure the displacement to determine fat percentage) and capture your true fat percentage. Women should aim for about 25% body fat and men should aim for 15-17% (which is acutally pretty fit). That is the only true test of obesity!!

Trovan · March 2011

Great info. Thank you.

My only exception to this is that BMI is astronomically easier for the layman to calculate. I don't even know where I get my BF% done.

ambrosij · March 2011

Search Amazon for body fat analyzer, for $25.00 bucks you can get what you need for an accurate measurement. The BMI is even less accuarate for men, especially those that like to lift. Men whose exercise regiments include lifting (which is actually the best way to lose weight because muscle repair burns more calories) will actually increase in weight before they decrease in weight, not lose weight at all for the first couple of weeks, or lose it very slowly. In fact, I would say it will drop off in chunks. That is actually what was happening to me when I dropped down to 168 in college. I would lost nothing for a week and then all of a sudden BAM I was down several pounds the next morning, I would plateau for a couple weeks then BAM another 10 or 15 gone. If you are significantly increasing your musle mass the BMI is simply useless.

hpsnickers1 · March 2011

Great, great post. I hope everyone on here reads it. We have to stop focusing on the wrong numbers, like the numbers on a scale. We are all different. I think the only way to measure at home is with body calipers. They still won't be 100% accurate but can give you a good number to start with. I don't believe in the bf% scales. I have one and have tested those numbers. I can step on the scale 2x in one hour and see a 2%-3% increase or decrease.

If I was that adamant on having it tested I would look for a place to get hydro tested. I'm happy with the calipers.

hpsnickers1 · March 2011

Search Amazon for body fat analyzer, for $25.00 bucks you can get what you need for an accurate measurement. The BMI is even less accuarate for men, especially those that like to lift. Men whose exercise regiments include lifting (which is actually the best way to lose weight because muscle repair burns more calories) will actually increase in weight before they decrease in weight, not lose weight at all for the first couple of weeks, or lose it very slowly. In fact, I would say it will drop off in chunks. That is actually what was happening to me when I dropped down to 168 in college. I would lost nothing for a week and then all of a sudden BAM I was down several pounds the next morning, I would plateau for a couple weeks then BAM another 10 or 15 gone. If you are significantly increasing your musle mass the BMI is simply useless.

that's something interesting to check out. Might be a future purchase.

RyonsLions2 · March 2011

Wow, women are to aim for 25% body fat?? Really?? That seems high to me. Is that because we should be doing some weights to get the muscles tone which adds weight? Excellent information by the way. Thanks.

mpzotter · March 2011

I could not agree more with this post. Ten years ago when I still worked at the Fire Department I worked out twice a day every day. I weighed 240 lbs and had a BF% of around 10 percent. BMI charts indicated that I was still overweight and in fact suggested that the top end of my normal weight range would be 210 lbs. I would have to lose a serious amount of muscle to get anywhere near that weight and I certainly would not be healthy.

I understand that BMI is a simple tool for lay people to get some idea of where their weight should be, but I think for a large portion of the population it is highly inaccurate.

jvdreher · March 2011

That is AWESOME information and should be shared with everybody! I feel the exact same way about that BMI chart. It is very unrealistic to me.

ambrosij · March 2011

The body fat scales arent so good, but the hand held analyzers are. In fact, most personal trainers and fitness experts are using the analyzers instead of the calipers. I was a little surprised to find this out as I was brought up with the use of the calipers as the most accuarate methody next to the water dunk. There are hand held analyzers that are in the higher dollar range, I would have to guess they are more accurate. But a good rule of thumb is to do multiple measurments. Keep taking measurements until you get three that are within three percent of each other, at least thats the trick I use with my inaccurate scale, which likes to jump 10% depending on where you step on it...so I would have to agree- the scales suck.

ambrosij · March 2011

Wow, women are to aim for 25% body fat?? Really?? That seems high to me. Is that because we should be doing some weights to get the muscles tone which adds weight? Excellent information by the way. Thanks.

See the following chart:

Classification Women (% fat) Men (% fat)
Essential Fat 10-12% 2-4%
Athletes 14-20% 6-13%
Fitness 21-24% 14-17%
Acceptable 25-31% 18-25%
Obese 32% plus 25% plus

As you can see 25% is on the edge of fitness/acceptable. Women naturally carry more fat than men, the reason for this is that a woman's body is designed to carry a fetus one day that will have to nurish off of the body, because of that the body stores fat in deposits that men dont have. Consider the breasts, this is a fat store that a fit woman may have that a fit man definately will not have. It is a common fallacy that a woman needs to eat more food during a pregnancy; the hormone HCG is produced while a woman is pregnant in significantly high numbers (so high it is thought to be the cause of morning sickness) the HCG hormone triggers the body to release those extra fat stores...but thats another discussion.

TrainingWithTonya · March 2011

Great OP! As a trainer, I couldn't agree more! Weight and BMI can both be wrong when it comes to health. Someone who is over weight can be very healthy if they are in a healthy zone for body fat and someone who is under weight can be unhealthy if they are under body fat. Technically, from what I've learned in school, it's healthier to be in the overweight range for BMI then to be in the underweight range. That's because their judgments are based on statistics for incidence of illness and death for each category.

For the other posters:

The most accurate way to get your body fat tested is actually now the DEXA scan, which is like an x-ray of the whole body looking at the various organs and yes, even body fat. But it can be very expensive and is usually only available through your doctor, plus there's that whole exposure to radiation thing. The next best is the hydrostatic weighing, but most of those are only available at hospitals and universities. You can call around your local area to see if there is one that will do the measurement for you. After that is the Bod Pod, which is air displacement similar to the water displacement from hydrostatic weighing. Again, usually at universities (this is what we have at my school), but there are some available at high end gyms. After that is bio-electrical impedance which basically uses a low voltage electrical current to run through your body and see how fast it goes. You don't feel a thing from the current and it gauges how much body fat you have because electricity moves faster through muscle, bone, water, etc. then fat. This is most accurate if it is one that you lay down and they hook an electrode up to your and and foot on the same side of the body. The handheld body fat analyzers and the scales use the same technology. The drawback to the handhelds and the scales are that they are inaccurate in that they are only measuring the upper or lower body (the path of least resistance between one electrode and the other). The scales are technically more accurate then the handhelds because the current goes through the hip/abdomen area where most people carry the majority of their body fat, but they can overestimate body fat % because of that. The handhelds can underestimate because most people carry less body fat in their arms and chest/shoulders. You can call around to local gyms to see if they have the full body BEI, though, and they shouldn't charge much for that assessment. The calipers are next in accuracy and again can be done at most gyms relatively inexpensively. The drawbacks are that you have to allow access to 3-7 pinch sites and it's not a gentle pinch (especially for men with body hair) and it only measures the subcutaneous body fat not the visceral body fat that is actually what is dangerous (its around the organs). The least accurate way to assess body fatness is the measurement formulas, as mentioned in the OP about how the Army does it. There are several different formulas for this and they vary in accuracy. The key if you use this method is to stick with the same formula when you reassess. That's really the key with any way of measuring body fat. If you compare a DEXA scan with a caliper measurement, you won't get the same reading most of the time, even when they are done at the same appointment. So, whatever method you choose to use to determine body composition, stick with the same method and don't compare apples to oranges.

For the person who questions the % for women, yes, we women are cursed in that we have to have estrogen. It works with our body fat percentage in order to protect our fertility. That's why when we drop too low in body fat we lose our monthly cycle, because we don't have a safe, cushioned place for babies to grow. If we go too high in body fat, we also have issues with our cycles because the estrogen/progesterone balance won't support a growing baby. Don't worry, you don't have to be exactly on the dot with a certain percentage to be able to have children, though, it's a range, just like anything else.

For anyone who might be interested, here are the actual ranges that we use to classify body fat % for both men and women. Essential fat is just to maintain normal organ and cellular function. Athletes, for women, are at risk of losing menstruation. I tell my clients to aim for fitness or average to be in the best health.

Men:
Essential fat--2 to 5%
Athletes--6 to 13%
Fitness--14 to 17%
Average--18 to 24%
Obese--25% and higher

Women:
Essential fat--10 to 13%
Athletes--14 to 20%
Fitness--21 to 24%
Average--25 to 31%
Obese--32% and higher

Debx12345 · March 2011

I have a bf of 33.7, so am classed as obese, but weigh 130 lbs, and bmi is 23.7, so question would be what am I doing wrong to get such a high bf ? And I have a hand held analyser like the one they use in gyms.

ambrosij · March 2011

First I would determine if you are getting consistent readings or if it jumps around alot. There are cases where people who appear to be in shape, or have an acceptable BMI are technically over weight based on body fat percentage. In fact, there is one clinical study where a Women who weighed 112 pounds went to a nutritionist and asked for help losing weight, the nutritionist diagnosed her with an eating disorder based on her body weight. When she went back to her doctor the doctor ordered a body fat test and low and behold she was in the low 30's. Once this woman got down to the 23-25% mark she weight between 87 and 91 pounds. She felt overweight and unhealthy because she WAS!!.

The first thing I would ask is what your eating habits and work out habits are. Secondly, have you had kids? And thirdly whats your age?

I have a bf of 33.7, so am classed as obese, but weigh 130 lbs, and bmi is 23.7, so question would be what am I doing wrong to get such a high bf ? And I have a hand held analyser like the one they use in gyms.

TrainingWithTonya · March 2011

I have a bf of 33.7, so am classed as obese, but weigh 130 lbs, and bmi is 23.7, so question would be what am I doing wrong to get such a high bf ? And I have a hand held analyser like the one they use in gyms.

I would need to look at your workouts and eating habits to give you an idea of what can be changed. The typical things I see in the gym, especially in women in our age group are that we don't work hard enough in the gym and we tend to eat too much fat in our diets. I don't know about you, but when my Momma taught me to cook, vegetables required butter and meat was fried. It took me years to re-learn how to cook and even now I have a tendency to want to use a little too much butter.

In the gym women tend to not lift weights at all or use way too light of weights when they do lift. And if they lift, they do so after cardio, which is backwards for getting the most fat burning from your workouts.

Debx12345 · March 2011

First I would determine if you are getting consistent readings or if it jumps around alot. There are cases where people who appear to be in shape, or have an acceptable BMI are technically over weight based on body fat percentage. In fact, there is one clinical study where a Women who weighed 112 pounds went to a nutritionist and asked for help losing weight, the nutritionist diagnosed her with an eating disorder based on her body weight. When she went back to her doctor the doctor ordered a body fat test and low and behold she was in the low 30's. Once this woman got down to the 23-25% mark she weight between 87 and 91 pounds. She felt overweight and unhealthy because she WAS!!.

The first thing I would ask is what your eating habits and work out habits are. Secondly, have you had kids? And thirdly whats your age?

I generally reads the same, may give or take a point.

I am 43, yes i have had kids.

My eating is pretty clean, don't cook with oils or butters, generally porridge for breakfast, fruit to snack, pasta or veg for lunches/dinners, low fat yogurts, eat little cheese or dairy products, and no meat. I aint no angel, do sometimes have a biscuit
or glass of wine.

My exercise is generally :
exercise 6 days a week, 4 days doing something like turbo fire (30 mins), and 3 times a week do light weights (30 mins) + treadmill (10 mins)

Trainingwithtony - i had arguement with my gym the other day, cos they put me on a programme that wasnt lifting higher weights, i was trying to explain that i wanted to burn more body fat so though i needed to increase my total weight lift, i go the gym again tonight, so do i need higher weights and fewer reps ? or am i talking rubbish ?

Debx12345 · March 2011

my maths isnt great 6 workouts at a 3 and a 4. Lol

but generally i try to do something everyday, even if its only for half an hour.

anyway help would be appreciated.

ambrosij · March 2011

Funny, thats how I learned to cook too. Pan fried meats and buttered veggies....cream, salt, butter in potatoes...but always water with dinner...hey at least we had that right.

I have a bf of 33.7, so am classed as obese, but weigh 130 lbs, and bmi is 23.7, so question would be what am I doing wrong to get such a high bf ? And I have a hand held analyser like the one they use in gyms.

I would need to look at your workouts and eating habits to give you an idea of what can be changed. The typical things I see in the gym, especially in women in our age group are that we don't work hard enough in the gym and we tend to eat too much fat in our diets. I don't know about you, but when my Momma taught me to cook, vegetables required butter and meat was fried. It took me years to re-learn how to cook and even now I have a tendency to want to use a little too much butter. In the gym women tend to not lift weights at all or use way too light of weights when they do lift. And if they lift, they do so after cardio, which is backwards for getting the most fat burning from your workouts.

TrainingWithTonya · March 2011

Deb,

Can you go any longer in your workouts? The days you are doing 30 minutes of weights followed by 10 minutes on the treadmill are great, but you need to up the treadmill time if you can to get more fat burning. Basically, the body has 3 energy systems and only one of them can use fat for fuel. That system is kicked in based on duration of activity and only if the other chemicals needed by the body to break down fat are available. The body pulls from the first two systems before it gets to the aerobic system to burn fat because the chemical process of breaking down fat needs the by products of the chemical reactions in the other systems. The first system is the Creatine Phosphate-ATP system. This is the one that basically uses the creatine phospate and ATP that is already stored in your muscles to do an immediate activity, generally something short (15 seconds) in duration and very high intensity. Think Standing Long Jump, or the jumps you do during a longer workout (the longer activity may be using the other systems, but the super high intensity jump will use CP-ATP). After that, your body uses the Anaerobic Glycolysis system, where carbs in the form of glucose or stored glycogen are broken down to make ATP that the cells can use to fuel activities like weight lifting or sprints that are pretty intense but only last a couple of minutes before you rest. A by-product of Anaerobic Glycolysis can either be converted to Pyruvate if there is adequate oxygen and the body is going to push on through to Aerobic Glycolysis or to Lactic Acid if there isn't enough oxygen available to the cells to go into Aerobic Glycolysis. As you may have guessed, Aerobic Glycolysis is the system that can burn fat. It takes that pyruvate and puts it through the Krebs cycle with the fat to produce a lot of ATP. It's the system that produces the most energy in the form of ATP but in order to make that much ATP it takes a long time. This is your system that you use when you do cardio (treadmill, bike, etc.) or when you do light weights and high reps with no rest weight training. The problem with doing just straight cardio or light weight, high reps, no rest is that it doesn't give the Aerobic Glycolysis system the pyruvate it needs to burn fat. So, you have to do some of the high intensity work first in order to provide that pyruvate. For years I've had my clients do their warm up of 5-10 minutes on the treadmill at a low speed, then go to their weight training. For most people I say to use a weight that is heavy enough that the last two reps are all you can do to get it without losing form. How many reps you do depends on what muscle fibers you want to train. If you want to build the type I (endurance) fibers, then 15 reps is good. If you want to focus on the Type II fibers (more ability to hypertrophy and build strength), then as low as 3-6 reps is good. The few the reps the more muscle growth because you can go heavier. Most people want to build a little strength and a little endurance, so they use 8 to 12 reps so that they don't go too extreme for specific fiber types. I typically give my clients who are short on time only about 15-20 minutes of strength work because that is sufficient to work the muscles when you go heavy enough and produce the pyruvate for fat burning during their cardio. After weights, I have them do at least 30 minutes of cardio at a moderate intensity. If you go too high in intensity you will be working Anaerobically and not Aerobically. While this is great for blasting lots of calories, it burns a much lower % of those calories from fat. If you go too low in intensity, then you will be working primarily Aerobically and no Anaerobic. While this sounds perfect to burn a higher % of fat, you aren't burning a whole lot of calories so it's really not a lot of calories from fat stores. Moderate intensity is optimal so that you burn more calories but keep a higher percentage of them coming from fat stores. After the cardio, then I have them cool down for 5-10 minutes with lighter cardio activities and stretching. Another way of training for fat burning is to do interval training. With interval training you alternate between high intensity, short duration (like weights) and low intensity, longer duration (cardio) so that you work in both the anaerobic and aerobic systems at the same time. It's good for those short on time who can't devote an hour to training, but requires a little better planning for your intervals so that you don't overtax one system or muscle group while ignoring the others. Regardless of which type of training you do, and especially if you mix them up, don't work the same muscle groups with weights two days in a row. Those muscles need at least 48 hours to repair and rebuild so that they can grow and burn more calories at rest.

As for eating, make sure you are eating enough. And especially enough carbs. "Carbohydrate spares protein" is the number one favorite expression in my nutrition program. That's because if there aren't enough carbs in the body to fuel the anaerobic system, then the body will produce its own glycogen from breaking down protein (either dietary protein or protein in muscles). When you are lifting weights you have to have the protein you intake available for repair and growth of those muscles, so you have to eat enough carbs to keep from the body needing to break it down for energy. Spare the protein for muscle building and repair. You need 8 to 10 grams of carbohydrates per kilogram of body weight and 0.8 to 1.5 grams of protein per kilogram of body weight to make sure you are repairing and rebuilding those muscles and fueling the anaerobic activity so that you can pull from those fat stores for the aerobic activity. The more intense your workouts, the higher in those ranges you need to go.

Debx12345 · March 2011

Wow excellent , might take me a while to digest all that info, but it's given me a start to work on, going to do a light warm up on the exercise bike, then do higher weights, lower reps, then finish off on treadmill, at the gym tonight. Am I in the right ball park ?

Will also give the hiit more of a try, have done the occasional one off turbo fire on DVD, but a few friends on here have suggested it as well.

Thanks, very informative and excellent post as always. X

ambrosij · March 2011

Actually,

What would work better to begin your work out is some active stretching, then go into some plyometric type things, like simple but kicks, grape vine, running back wards, side step, skipping. Then as your heart rate picks up get in some real short sprints, and maybe finish with 30 seconds of jump roping x 3 with a 15 second rest between each round. This will take care of that initial energy burn and start that chemical reaction the previous poster was discussing. This is a sufficient warm up.

Wow excellent , might take me a while to digest all that info, but it's given me a start to work on, going to do a light warm up on the exercise bike, then do higher weights, lower reps, then finish off on treadmill, at the gym tonight. Am I in the right ball park ?

Will also give the hiit more of a try, have done the occasional one off turbo fire on DVD, but a few friends on here have suggested it as well.

Thanks, very informative and excellent post as always. X

Don't let the BMI get ya down...focus on BF%

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