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krobinson103 04-08-12 08:25 PM

How realistic is optimum weight calculated by the BMI method?
I was 102kg. I now weigh 94.5kg and am close to my goal of 90kg. But, according to any BMI calculator 85kg would be optimum. This seems ridiculous as at 90kg I'm a walking skeleton. I'm 190cm tall and while not hercules have at least decent muscle development. To me 90kg is about right but every where I look 85kg seems to be the 'target'. What gives here?

Daspydyr 04-08-12 08:50 PM

I have heard a number of things are disputed when it comes to a standard BMI chart. I would look like your twin if I got in the target category for me. I think your blood pressure and resting heart rate are good tools to evaluate your health. Bicycling Magazine also has a charting system this month to help you calculate your best riding weight. I am playing with the chart. It is still a tad on the low side weight wise for me. But still allows me 15 more pounds than BMI. I am 6' 3" and 225. Hope to get to 210-215 by May. 200 is too low for me Bicycle Mag chart. 180 is stupid for me.

Mr Sinister 04-08-12 08:56 PM

BMI is not the best way to judge. It is only a good way to start, and get yourself going. It takes no muscle mass into consideration, and by not doing this, any and all body builders are obese by this standard.

A better bet is to go to your doctor, or a trainer at a gym and have them messure your body fat percentage. This is done with calipers. They will check your chest, gut, and legs at least. They can also check the tricept area of the arms.

Shimagnolo 04-08-12 08:58 PM

I'm 6'2".
2 yrs ago I dropped my weight from 197 to 180 over 6 months.
My blood pressure dropped from the pre-hypertension range (~ 135/90) to 120/78.
My cholesterol dropped so much that my Dr took me off the meds temporarily to see if I could be taken off permanently.

I was surprised that little weight loss made such a difference. I was only doing it to improve my climbing.

krobinson103 04-08-12 09:08 PM

Resting pulse rate at 66bpm, blood pressure... Can't remember exactly but it was lower than average a month back. My last physcial checkup including bloodwork showed only 2 things wrong. Cholestrol .05 over the 'norm' and a higher than ideal body weight. Fixed the cholestrol with diet changes, lost a bunch of weight and plan to lose more. I can run 4 miles now, I can cycle 30 miles at 20 mile an hour and not feel tired and I have a lot more energy. I think I'm fairly healthy for a 38 year old. But 85kg just seems... absurd.

TrojanHorse 04-08-12 10:51 PM

We're practically the same height (I'm 6'2") and I'm having trouble imagining you as a skeleton at 200 # (90 kg).

The lightest I've been in the last 15 years was about 195 and that was damn good (ie far from skeletal). The BMI charts tell me that "normal" for me would be 145 - 190 and I totally agree that the low end of "normal" would be "cadaver ready for science"

Having said that, if you're fit & happy, don't sweat it. Do pay attention to BP & blood indicators and stay active. Go for 60 miles next time. :)

krobinson103 04-09-12 05:06 AM

I need to increase my average speed a little to get 60 miles in and still have time to be Father to 2 kids. The best I get away with is to get up uber early every morning and get as much time in as possible. On the weekdays that around 20 miles. On the weekends I can get away with a little more. Perhaps even out to 100km, but it would come at a cost, my wife would never stop talking about it. Last Sunday I felt like crap with a cold so I just setup the old bike with a super strong rack and put a seat on it for my eldest. I've really missed riding with her riding shotgun. :)

Not sure. Give it a month and I'll be at 90kg. If I can still find some room to lose more I'll shoot for 85kg. Funny thing is my wife was the one who got this whole thing started and now I get "don't exercise so much!" Can't win either way.

vesteroid 04-09-12 07:19 AM

I decided to go by fat. To me it's simple, whatever muscle and skeletal structure you have, you have. The rest is fat. I don't have a measurement tool, but I can pinch under my biceps, around my mid section, and under my legs, and tell if I am still fat. If I am, I simply keep trying to lose weight.

I hope with all this exercise, I am gaining at least a little muscle ( although I don't thin you gain nearly as much as people say you do)

I hope one day this year I will finally be able to say I am not fat anymore, but I still have a long way to go. 6'5" and 230 now and I could easily lose another 30 and not be skin and bones.

tony_merlino 04-09-12 07:56 AM

The BMI method doesn't factor in gender, age or body type. When I was in my twenties, I had a BMI of about 20. My waist was 29 inches and I wore a men's small shirt. It was ok for a 25 year old in the 1970s. If I weighed that now, I'd look like a walking corpse. The last time I got to a BMI of 22 or so, in my early 50s, everyone told me that I looked wasted.

My goal now is to get to a BMI of about 25, as long as that doesn't look too emaciated.

TrojanHorse 04-13-12 11:31 AM

I hear you on the time required to cycle - it's the biggest negative as far as using cycling as a form of exercise. Running is fast and effective, but I hate it.

I squeeze in rides when I take my son to practice (2 hours for him, so once you factor in parking & getting ready, I can get in about 1:20 on the bike and be back in time to pick him up) and then as you mentioned, ludicrously early starts on the weekend if I want a longer ride.

It's definitely a balancing act.

goldfinch 04-13-12 12:24 PM

If you do not actually get your body fat measured you can get a rough approximation by taking measuring your neck, waist, hips and height:

According to measurements I am still a bit higher than I want on body fat even though my BMI is 21.3 after losing weight. I am not surprised.

Tundra_Man 04-13-12 02:52 PM

Every year my son's school does a BMI calculation on all the kids.
Every year we get a form letter informing us that our child is borderline obese.
Every year we crumple up the letter and throw it away.

Anyone who looks at my son (now age 9) can tell this isn't true. In fact, I wish I had his six-pack abs.

I don't put too much stock in BMI numbers.

squirtdad 04-13-12 03:26 PM

BMI is not at all accurate on an individual basis, it is accurate for a population, meaning there are extremes on either side. And as I undertand it it was never meant to be used is it is...and absolute. It is also supposed to be further off for atheletes.

For me personally it seems really off. at 6 feed per BMI should weigh between 140 and 184. I could see 184 but I would be really skinny....last time I was close (190) I was training hard for a triathalon (and was under 35 and was single). Below that much I would anorexic looking.

One of my doctors did a odd little screening test for bone size. He had me wrap my hand around my other rist. I couldn't touch my thumb and middle finger together...suggesting large bones..... he gave me a targe of 200 lbs

youcoming 04-13-12 03:46 PM

I'm 6'1" and gunning for 180 or less, not training for any event just want to see where my limits are on the bike. I love climbing and I know hills never get easy you just get faster up them and the less there is of me the faster I will be, that is as long as I keep muscle. BMI means crap in the big scheme but I'm using it, I'm at 213 right now and I by no means look skeletal.

krobinson103 04-13-12 07:49 PM

Don't really care about speed, though it seems every day it gets easier to go faster - especially on the hills. Just looking to get myself back into shape before I hit 40. Have to say that today I rode 51km in 2 hours 20 minutes (including some brief stops) and I feel like I could do it all again. Feels good to have that sort of energy again. :) Hit 93.8kg today and my body feels oddly light. I guess 8kg of extra mass does indeed slow you down.

MadCityCyclist 04-13-12 07:57 PM

It's not body muscle index, now is it? That pretty much sums it up right there.

krobinson103 04-13-12 08:59 PM

I remember going to a gym where they had some kind of high end scale that had 2 extra clips to analyze the composition of your body. Not sure how accuate such a device is, but perhaps it might be worth going somewhere with either the appropriate foreceps, or a gadget to actually find out how much fat there actually is...

rwwff 04-14-12 08:26 AM

Considering I'd have to have a seriously negative body fat percentage to make the suggested weight, its not particularly useful in all cases. Its a good "head's up" if someone hasn't been paying attention to anything and just parking on the sofa though. Once you are athletically inclined though, if you are interested in this sort of info, you need to get a body fat % measurement to know anything useful. They do have some relatively inexpensive electro-zapping scales now, so you could DIY if you wanted.

linear 04-14-12 11:24 AM

The normal BMI range may not be realistic for some. I would like to get to the top of the normal range 184# but it has been a few decades. I would hate to go the effort to to lose down to an unrealistic weight that I could not maintain, as that is the hard part. I can gain quite fast but losing seems to be getting harder. Good luck with your weight loss endeavour.
The bottom of the normal range would not work for me, pretty sure of that.

contango 04-14-12 11:27 AM


Originally Posted by krobinson103 (Post 14075279)
I was 102kg. I now weigh 94.5kg and am close to my goal of 90kg. But, according to any BMI calculator 85kg would be optimum. This seems ridiculous as at 90kg I'm a walking skeleton. I'm 190cm tall and while not hercules have at least decent muscle development. To me 90kg is about right but every where I look 85kg seems to be the 'target'. What gives here?

I tend to use BMI as a guideline only.

When I started cycling I weighed in somewhere around 290. The highest I ever specifically saw on a scale was 287 but I only very rarely weighed myself, largely because I didn't like the numbers. At least once I used a scale that went up to 280 and I was somewhere over 280, but couldn't accurately gauge how far over. At about 6'4 my BMI was around 35, or "morbidly obese". There was no mistaking that I was fat but morbidly obese isn't a term I think was appropriate, even with the benefit of hindsight.

According to BMI charts I think I'm supposed to be somewhere around 180-190. I'm currently 230 and although there's still room to lose more from around my middle I'm wondering if I can sensibly go below about 210 without looking like a stick. Cycling has taken a lot off my stomach and put a lot of muscle on my legs, which is heavier than the fat that I lost. For the longest time people were telling me I looked like I'd lost a lot of weight even though the scale stayed resolutely the same.

Jonny Wilkinson, who plays (or at least once played) for the England rugby team, was reported to have a BMI of something like 29.6 which meant he was bordering on obesity.

Bottom line, I'd say use it as a guideline but take it with a pinch of salt, especially if you're doing anything that will cause you to lay down more muscle than the average person might carry. Other metrics will give you a better idea of where you are as opposed to where you fit on a one-size-fits-all scale that doesn't fit everybody very well.

chasm54 04-14-12 11:37 AM

OP, I'm almost exactly your height. I'm of medium build, square-shouldered, fairly big-boned. When in what I regard as top shape I am about 85k, a BMI of 23. So it works for me.

And it works for most people. That isn't too surprising, because it was devised as a population measure, not an individual measure. That is, in a given population, the incidence of degenerative disease increases in synch with increases in the number of people with BMIs over 22.

Of course, there are exceptions. Heavily-muscled athletes with low bodyfat percentages score high BMIs. But to be fair, there aren't many of those people around. Most of the people who complain that BMI isn't an appropriate measure are simply in denial about how fat they are; and their numbers are increasing as being overweight becomes the social norm.

Congratulations in advance for when you hit 90k. Bt when you get there, don't be surprised if you decide there may be a bit further you could go.

lucienrau 04-14-12 12:44 PM

It really depends on your build. If my brother were at a 'normal' bmi he'd be fat, me, I'm 6'2" and very broad shoulders. BMI says I should be around 185, I've been 201 once as an adult when I was very sick for a long time. Skinny and unmuscled puts me at around 215. I'm lifting and working with a trainer so with a much lower percent body fat and all that I'll probably balance out at somewhere between 240 and 250. I'm at 277 now, my lightest was 273 and I'm skinnier than I was then.

No matter what I'll still be obese according to bmi, even though I'm 6% body fat less than when I was very heavy. My dr and trainer keep saying cholesterol, blood pressure and resting heart rate are better indicators of health than weight or even looks.

Torrilin 04-14-12 01:59 PM

A better guide might be military standards. For example, I'm 5'6", so to meet the USMC standard I'd need to be between 106 and 147. My partner is 6'2", he'd need to be between 139 and 214. I've got ample data that my athletic performance is utter CRAP at anything under 130, so for me the low end of the range is not ok. I've been down as low as 105 as an adult, and I did not have any real strength or endurance. Didn't have the energy for most activity. I was cold all the time. Lots of bad stuff. Once I'm over 130, life is better.

There are women my size tho who *are* ok at 106, and do well athletically at that weight. And my partner does well athletically down pretty low in the acceptable range for Marines of his size. So it really does depend on the person.

ArchEtech 04-14-12 07:40 PM

Totally depends on body type. I'm 5'9" to 5'10" and weight 225 which by BMI is obese. But I'm 10% body fat, and can't bench over 400 lbs so I'm not built like a normal person. Some people do have bigger bones, and thicker builds. Body fat % (by using only accurate tests) is a better measure. In any case, blood pressure, pulse and general fitness levels is a better measure of health than a chart.

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