Weight Loss Support - Does BMI actually mean anything?

View Full Version : Does BMI actually mean anything?

03-23-2014, 03:57 PM
According to the upper limits for a "normal" BMI range, for my height I'm supposed to weigh 145. If I weigh 146 I'm overweight. Personally, i think 145 is too skinny for me and I can't even imagine myself at that weight.

What, if anything, should we think about BMI? Is it really a marker for good health? I template to work off of? Is it just general guidelines?

03-23-2014, 04:37 PM
I tend to follow BMI charts..I'm teetering on the overweight category but I'm okay with it as long as I'm within normal range.

03-23-2014, 04:57 PM
If you're perfectly average, it's probably a decent guideline, but if you're very athletic with more muscle than the average, then the BMI guidelines are too low. If you're more sedentary and undermuscled than average, the BMI guidelines would be a bit high.

BMI guidelines are probably a bit generous for me right now because I'm not very active, but I'm working on that. One day I would love to be more muscular than average, so that my ideal BMI might eventually (in theory) fall in the mildly overweight category.

Also, BMI isn't designed to calculate ideals, just averages, so I think at best it's a ballpark starting point, and nothing more. Finding your own unique best weight and best activity/athletic level requires further tweaking/trial and error.

03-23-2014, 05:42 PM
Absolutely not. A friend of mine who is in the Navy is very fit and quite muscular. According to his BMI, he should lose 30 lbs to be normal weight.

03-23-2014, 06:11 PM
Like kaplods said, it doesn't work for muscular and not muscular people. It also doesn't work for too tall or too short people. So, basically, it's for average people just like kaplods said.

I used to think that 152 tops wasn't for me. I thought I'd be too thin and that it would be difficult to maintain. But now I'm here and I can definitely stand to lose more. I've chosen 130 as a goal for a completely ridiculous reason: years ago I saw in a Dior ad that 130 is the ideal weight for my height. I was a kid then and I decided that I'd get there some day. But I like to have a number to aim for. So, I'm going for 130, but I could stop before I get there or I may get there and then keep going. I have no idea.

I haven't weighed this low since elementary, so I don't know what I'll look like 20 pounds from now. I have a friend who used to weigh 160 pounds, she gained 53 pounds and she wanted to get back to 160. She did and now she wants to keep losing because she has more fat now, so she's bigger than she was.

So, I believe that you can't really know what you're aiming for. Just keep losing and stop when you think that you look good and that you will be able to maintain your weight.

03-23-2014, 07:46 PM
That's a good point. I have 165 as my goal now, but who knows what it will be like when i'm actually there. It's hard to say what my "body makeup" is. I've always been strong, and I've played soccer all my life up until I was about 22 - so I know the potential is there for a muscular body and i think it still might be there under a few layers of fat lol.

I'm still going strong at the gym and I can see a noticeable increase in my strength already. My roommate was shocked yesterday when I told her my weight and said she would have pegged me for at least 20lbs less (she's someone of similar stature) so this leads me to believe that although I'm fat the BMI might not be a very good measure for me. Heh, i guess just wait and see until I get there!

03-23-2014, 08:16 PM
Exactly what kaplods said. BMI was developed to be an accurate measure of health in populations of people, and it's great for that. For individuals, though, it's just a ballpark figure, and it isn't necessarily accurate for everybody.

03-24-2014, 10:18 AM
I was remembering something I posted about this topic on another thread a few years ago, so went searching and found it:

It's one tool, one metric, and it's useful as far as it goes. It shouldn't be given more value than it has, though. It's not a be-all, end-all metric of health for every person.

Averaged over populations, though, it has a lot of value. And for most people - people who fall under the big part of the bell curves for height, musculature, etc., it probably gives a pretty good indication of ballpark ranges of weights that are healthy versus ballpark ranges that are not.

And I suspect that a lot of people probably fall under the big part of the bell curves who believe, for whatever reason, that they do not.

I will use myself as an example. The BMI guideline puts the top of the "healthy" weight range for a 5'5" woman at 150 pounds. For the longest time, I thought, that doesn't apply to me; I could never, ever be healthy at 150 pounds. After all, I am built like an ox, with strong muscles and a very powerful core, and I have very large breasts. So I must be one of those people who falls outside the average range that the BMI charts cover.

Well, guess what? I now weigh 164 pounds, less than I've weighed in 23 years. And I have to tell you that looking at my body now, 150 pounds seems totally reasonable and doable to me. Looking at my body fat percentage (still around 28%), looking at my saddlebags and my belly, I can readily stand to lose another 15 or 20 pounds, putting me well within the "healthy" range for those BMI standards, despite all my muscle and boobs.

Now that I'm not fat anymore, I can see that I'm not as much of an outlier as I thought I was. While it's still true that the low end of the healthy range is not realistic or healthy for someone of my build, the high end most certainly is - that's why the healthy range is a range.

So, I'm less down on BMI as a guideline than I used to be. Applied to averages over populations, it's still a pretty useful measure of overall health. And applied to individuals, more people fit within the guidelines than you might think.

03-24-2014, 10:29 AM
Trust me, you will not be skinny at 145pounds. I am only half an inch taller than you. I've been as skinny as about 115 or even less i can't remember what the lowest i ever was but it was very small, not anorexic but as close as i can get to that without being considered sick.

Just enjoy yourself and your new body as you go and don't worry so much about the future. Deal with it when you get there. You'll see.

RAther than worry too much about what you might look, think a little bit about how you are going to maintain it. Don't go relaxing too much. People with a history of bad eating habits can't really afford to relax too much about food. At least not for a very good while of maintaining.

I'm saying this to you but its something i'm telling myself more or less every day. Not in a deliberate way but just thoughts that come to mind and i'm aware of because of past experience.

03-24-2014, 10:37 AM
Oh sorry back to the question. In the absence of anything better, i think its an accurate guideline for the greater majority of people.

BMI is calculated on height and weight and takes into account how much muscle mass and fat a healthy person would be at their age.

There is also the healthy weight range which is given in pounds and kgs not in bmi. It is probably easier to understand than BMI.

Personally i think its good to aim for the middle of the range because if you take your foot of the break too soon, you might go back up too soon. If you aim for the bottom of the range, you might push the limits of what your body will allow before it tries to rebound. That happened to me last time. I am trying to avoid that this time. I know it can be done. I know i can reach the bottom end of the range and stay there but it should be done slowly and carefully and i don't think i need to be that skinny really. Its too much effort.

03-24-2014, 10:41 AM
According to the upper limits for a "normal" BMI range, for my height I'm supposed to weigh 145. If I weigh 146 I'm overweight. Personally, i think 145 is too skinny for me and I can't even imagine myself at that weight.

What, if anything, should we think about BMI? Is it really a marker for good health? I template to work off of? Is it just general guidelines?

I am 6'1" and lived most of my life between 145 and 150lbs. I didn't look sick or too skinny. I think you'd be fine.

03-24-2014, 10:43 AM
Another thing I wanted to throw out there is that frequently, few people keep that strong of a track of their weight, much less actually report it. So often because so many of us keep a tight eye and report our true weights, we surprise people because people (in the general population) in my experience are often surprised when they hear about anyone's real weight/where they fall in the BMI range.

03-24-2014, 10:49 AM
I, myself, prefer this BMI calculator


and this is the weight chart I prefer:


Here is headless me at 6'1" tall (73 inches) and 150lbs exactly
http://i271.photobucket.com/albums/jj135/iwasbornonahorse/e112edb8-e080-4c53-8aa1-4875757cbf1f_zps1dd0bf62.jpg (http://s271.photobucket.com/user/iwasbornonahorse/media/e112edb8-e080-4c53-8aa1-4875757cbf1f_zps1dd0bf62.jpg.html)

03-24-2014, 11:24 AM
I will probably be one of the few that goes against the grain. I don't base anything off of BMI charts. If I happen to fall into one at some point, so be it, if not, so be it. The goal I have set for myself will leave me in the over weight category on the BMI chart. However, it is also the weight I was as a senior in highschool, on 3 different sports teams, with a very muscular build. At that time, being a self conscious teenager, my doctors reassured me I was extremely healthy. Being healthy doesn't necessarily equate to where you land on a chart. If I get to my goal and more weight comes off, so be it. I've changed my lifestyle and am becoming who I want to be, regardless of what percentile I fall into. Good luck.

Mrs Snark
03-24-2014, 11:58 AM
I've always found the BMI a useful guide.

I'm 5'9, currently 147, and I'm pretty muscular with broad shoulders -- though not very big-boned. My BMI, 21.7, is fairly in the middle of the normal range (18.5—24.9 is "Normal").

The CDC calculator I used said : "For your height, a normal weight range would be from 125 to 169 pounds."

That's a pretty big range.

03-24-2014, 01:22 PM
In my opinion BMI is almost useless. The only thing it is good for is to assist an obese person to pick a starting target goal weight. Why do I feel this way?

BMI is not an indication of health. You can be skinny and about to die or overweight and incredibly healthy. Diet and lifestyle determine health, not your weight. I qualify this of course with the knowledge that past a certain weight your health will suffer especially long term but BMI will not help you find this point.

BMI doesn't tell you how you look. You can be a healthy BMI and feel you need to lose a lot still or you can be "overweight" and perfectly content.

BMI was not created to measure anything with an individual.

03-24-2014, 01:43 PM
Here is headless me at 6'1" tall (73 inches) and 150lbs exactly

Looks like we have similar body types. I'm 5'11" and weigh 145 lbs. I also don't look skinny.


03-24-2014, 02:06 PM

That is a fantastic article about BMI.

If you want a quick and easy number, waist size is much better. Men under 40 and women under 35 inches have much better health outcomes.

BMI not only is totally wonky with the squaring, but it takes no account whatsoever of the difference between muscle, bone, and fat. Most NFL players with under 10 percent body fat would be 'obese'.

But it is barely useful even for the general public.

03-24-2014, 02:31 PM
I think everyone else has pretty much hit the nail on the head.

The BMI guidelines work, in a way; but are they perfectly accurate for every human being? I would say definitely not and it would be dangerous to say otherwise. So many doctors I've gone to have focused on that with me, and last time I was losing weight it bothered me greatly that I seemed so far away from my ideal BMI weight. For me, the highest weight I could possibly be is 159 pounds. I've never been under 213 as an adult, so I can't even imagine it!

It was always funny to me, because from the weights 225-213 people were already complaining I was getting too thin. I knew I definitely wasn't but I heard some mention it. By BMI standards, I was still obese at that time! I never even managed to reach an "overweight" status.

I don't mind using the BMI as a tool, but I find it less reliable than other means of measuring my progress and I'll certainly never measure my health by it.

03-24-2014, 02:52 PM
BMI is a starting point but so many other things come into play... interesting quote from a clinical Endocrinology study:

Conclusions: Increasing paternal age at childbirth is associated with a more favourable phenotype in their children (taller and slimmer, with better insulin sensitivity in girls) but with a less favourable lipid profile.

So even though BMI is lower, the LDL/HDL profile is less healthy...

Here's the whole article if anyone is interested

This site is a Health Professionals' Continuing Education site.

Quick quote - sorry but it is quite 'scientific' in language - but extremely interesting nonetheless.
"As paternal age at childbirth increased, their children displayed a reduction in BMI and truncal fat. As BMI in childhood is predictive of adult BMI, our findings suggest that the slimmer children of older fathers may have a lower risk of obesity in adulthood.[18] Increased truncal fat is a component of the metabolic syndrome, so that the children born to fathers aged over 30 years may be at a lower risk of metabolic disease and obesity. Importantly, the observed improvement in insulin sensitivity seen among girls born of older fathers would support this hypothesis, as a reduction in insulin sensitivity is predictive of the metabolic syndrome in adulthood.[19] Nonetheless, there are conflicting reports regarding the effects of paternal age at childbirth on offspring obesity. In contrast to our study, a recent large investigation found an increased risk of obesity in young adult offspring in association with increasing paternal age. However, this was only observed when groups at the extreme of the paternal age spectrum were compared (<20 vs >50 years).[8] Furthermore, unlike our study, they only examined males and parental BMI was not accounted for in their analyses to correct for genetically determined obesity.[8]

However, increasing paternal age at childbirth was also associated with less favourable lipid profiles in their children. Specifically, children of fathers over 30 years of age had higher total cholesterol to HDL-C ratios compared with the children of younger fathers. Childhood lipid profiles worsened as paternal age at childbirth increased further, so that the children of fathers aged over 35 years had higher total cholesterol (due to higher LDL-C concentrations) than children of fathers aged ≤35 years. Childhood lipid profiles track or accentuate into adulthood.[20] It is therefore possible that the less favourable lipid profiles in these children may deteriorate further later in life, placing them at a greater risk of cardiovascular disease in adulthood."


03-24-2014, 04:36 PM
Here is headless me at 6'1" tall (73 inches) and 150lbs exactly

Looks like we have similar body types. I'm 5'11" and weigh 145 lbs. I also don't look skinny.


I can go as low as the upper 130s and still look fine. No one is accusing me of starving or being too thin in that range.

03-24-2014, 04:53 PM
I think BMI is pretty realistic for the average person, as everyone has said. Body composition is everything.

I have maintained between 125 and 130 for over two years now. In that range I have had periods of lots of exercise and very little, so even though my weight barely changes, my clothing and overall "look" vary a lot.