Healthy weight based on BMI?

I'm 4'11" and am 112 lbs. during a cut, 118 lbs. on a regular basis. Which is technically "overweight" but my BF% is about 16% so it's all relative. More muscle = more weight, but doesn't mean less healthy. Go by how you feel and what your doctor advises.

MikePfirrman wrote: »

This recent study points out that Waist to Height ratio is a much better predictor of obesity (both in general and abdominal obesity) than BMI. The general rule of thumb is you want your waist to be half the size of your height, so for you, your waist should be under 30 inches. When you start creeping above 31/32, you probably need to lose some weight.

https://www.sciencedaily.com/releases/2017/06/170606090942.htm

According to BMI, I'm around 10 lbs overweight but according to this measure, I'm fine (I'm 5' 10" with a 33 inch waist). In general, I find this to be pretty accurate. Most people that are lower body fat will meet this second criteria when they "fail" the first.

I read an article about WHO using this by giving people a length of cord that was half their height. They were doing this in remote villages. Whether or not they were convincing native villagers that it was important is another matter entirely.

The thing I wonder about with that one is why the waist and not the abdomen (gut)? I lost a lot more circumference in the gut than the waist. I did use BMI and my waist measurement did not change much between 26.5 and 24.5 but my gut shrank quite a bit. Right now I have a 31" waist and I am just under 5'8" and weigh 157. Using 5'7.5" in a BMI calculator, that's 24.2 while waist to height is 31/67.5. In my case, i think BMI may be more accurate; I am near the top of healthy and only a few more pounds would push me into the low end of overweight by BMI and a waist under 33" would say I am healthy by WTHeight. I think BMI would be correct.

BMI is a difficult kettle of fish, but generally, yes, it's a pretty good indication of how much you should weigh. However there is a few things to think about. BMI is made for the majority and not for the people at the extremes. Those who are very tall, or very short, will find that BMI doesn't make as much sense for them. However, it is useful to bare in mind that it is still a useful tool. The bands are reasonably large to allow for some of this type of variation.

Another exception is if you have a larger amount of muscle mass. Because muscle occupies less volume than fat (per unit mass), you will appear to weigh less than the scales would suggest. (and there's plenty of health benefits to having some muscle mass)

It sounds like your doctor hesitated because they were probably mentally calculating your BMI, and then measuring up if you were the type of person for whom BMI isn't a good indicator for. At your height, 120 would be near the top of the healthy bracket. I assume that you're probably not carrying that much muscle mass, so for your height it seems like a pretty fair target.

However, in answer to your question, if you're intending on losing weight anyway, does it matter greatly if where you currently are is unhealthy? Unless you need more motivation, isn't this question somewhat academic?

Being slightly overweight by BMI only barely ups most health risks statistically in any case. You would need to hit the obese category to see a substantial jump in risk factors.

But you will still probably look and feel better at a lower weight. Good luck!

nadnan91 wrote: »

I went to the doctor this morning and when I got on the scale, it read 132 pounds. I asked the doc about how I don’t think I am currently at healthy weight based on BMI but I’m not sure since not everyone considers BMI to be the best indicator of physical health and well being. She hesitated for a second and said “technically you are overweight by BMI standards (I am just about 5 feet tall), so if you lose five pounds great and if you lose ten that’s even better. It’s best to stay under 120 pounds for someone of your height and stature.” I already want to go down to 117-118 but now I’m actually concerned based on what she said (maybe that’s a good thing if it motivates me to lose weight even more). Am I putting my health at risk by weighing in the 130s? Thoughts?

I imagine there is not a massive health risk being 10-15 lbs overweight. It is probably more important if you have a health condition or a high risk of developing a health condition that weight contributes to.
A medical professional told you that 127 or 122 were okay for you and 120 or less was probably best. Your goal was already in line with that thinking. Why are you concerned about the risks of remaining your current weight since you do not intend to?

5-10lbs is not usually going to have a really drastic effect on health. If you were "obese" or over, then I'd maybe be concerned, "overweight" not as much (not saying there's no risk, just that I wouldn't say it's anything to worry about, especially as you want to lose weight already)

BMI does not take into account body composition, or other health indicators, only weight and height.

BMI was originally meant to be a tool for looking at populations as a whole and assessing their general health/risk - not individual people.

Yes, on average you are slightly more at risk for certain health issues. I wouldn't be worried. You want to lose weight, your Dr has said this would be best. There's no resistance by the sounds of it, or any indication of potential barriers to achieving this, sounds like you both agree. It's more a case of you doing what you are most comfortable with at this stage tbh.

motivatedmartha wrote: »

My view is that BMI was developed as a statistical tool to determine the health of populations. The weight ranges covered by the descriptions used are pretty broad and it will apply to the vast majority of people who fall within a normal distribution curve. There will be exceptions but unless you are an athlete with very well developed musculature, or exceptionally lean, it will probably fit you. Medics have often been surprised, even when I was young and fit, at how heavy I weigh; often around half a stone heavier than they were expecting me too. Even with that, BMI fits me. For aesthetic reasons I will probably stop towards the top of healthy range but I will see (very soon I hope!). Having said that, a few pounds into the overweight category wil probably not be doing you any damage but is a good indication that you would be better off watching the pounds - they have got a habit of creeping up on you. Good luck and be happy.

This is one of the better answers I've seen here. However, people usually misinterpret what is meant when we say a statistical measure is meant for "populations." All statistical measures are meant to determine something about a population, but that doesn't mean they can't or aren't designed to assess risks on an individual level. When statisticians say something is meant to assess risks in a population, what they mean is they have taken a sample from a certain population of people in order to estimate a parameter which can then be applied to assess some probability for other individuals or groups in that population. For example, if we take a sample of university students and estimate their score on a calculus test based on how much they study for it, we have a parameter we can use to predict test scores for the population of university students based on the amount of time they study. This has two important points:

1. Because the sample came only from university students, we can only accurately apply this statistic to the population of university students. We don't know how this applies to other people. Maybe university students already have some sort of knowledge which helps them on the test that the general population doesn't. So studying for one extra hour as a university student may increase your score by 10 percentage points, but only 2 percentage points for those with a lower education level.
2. Just because we say this can only be applied to the population known as university students, doesn't mean we can't use it to assess outcome likelihoods for individuals. We can use it to estimate individual scores with varying degrees of accuracy, but only if the people come from our select population known as university students. Let's say our confidence level is 99%. We can use this to say that, with 99% confidence, Student A who studied for 2 hours will score 10 percentage points higher than Student B who studied for one hour.

BMI works similarly. It estimates parameters for a "population" based on sample parameters, but that doesn't mean it was only meant to assess risks for a population as a whole. It is meant to serve as a easy way to estimate whether or not someone has a healthy body fat percentage based on certain criteria. It is accurate to within whatever confidence level is chosen when estimating these parameters and it applies to whatever individuals come from the population we estimated it from (in this case, adults of European descent). Obviously, there is an error rate, so some people will not fall into the correct categories, but error rates for scientific assessments such as these are usually no greater than 5% total (2.5% at each tail, meaning 2.5% will be classified as overfat when they are not, and 2.5% will be classified as underfat when they are not). The other thing to note is that this estimation was done at a different time, so it's very likely the estimate for a healthy BMI has changed over time, but given the fact that the western world has increased it's calorie consumption and become less active in the past few decades, it's unlikely that BMI overestimates the number of people with an unhealthy body fat percentage and more likely that it underestimates it.

In Short: BMI is a fairly accurate predictor for the average person, and can be applied to assess risk at an individual level. It is also possible that BMI today underestimates body fat percentage categories.
Saying it is a predictor meant for populations is a misinterpretation of how statistics works and can be applied. We use statistics derived for population assessments all the time to assess individual risk, that's how insurance rates are often calculated, and, since insurers do not regularly declare bankruptcy, it's a pretty good sign that these estimates are pretty accurate. If you're not someone who has been an athlete for a few years, BMI is very likely to be an accurate picture of your health risks, and possibly even an underestimation. It wouldn't hurt to follow your doctor's advice of losing some weight, but it also wouldn't hurt to do a "recomp" and try to reduce just your body fat percentage by increasing your activity level.