BMI has been a widely used traditional “indicator” of good health for years. It’s a parameter to determine risk factors for a variety of chronic diseases that health professionals are taught in school.
Weight in grams divided by height squared in meters = BMI
Primary care doctors use BMI often as one measure of “good health.”
Dietitians use it to determine whether an individual is underweight, a healthy weight, or overweight.
And I hear all the time of personal trainers encouraging their clients to get under a certain BMI no matter the cost. Whatever it takes.
But does BMI matter?
As an RD and RN, I think BMI means absolutely nothing.
One of my favorite meals right now – cauliflower and brussels sprout rice with all kinds of Indian veggies and a little shredded organic chicken from a place called Inday, aka Indian Chipotle
It doesn’t take into account waist size, muscle mass, or bone size. In esssence, it makes no physiologic sense. Bone is denser than muscle and two times as dense as fat, therefore a person with strong bones, good muscle tone and healthy body fat is going to have a higher BMI compared to someone with little muscle tone and thinner bones who might be “healthy” by BMI standards, but actually not healthy.
one of my favorite snacks right now – 2 T chia seeds + 1/2 cup cashew milk, topped with cashews, banana and chunky AB
This is exactly why athletes or even physically fit people find themselves with a higher BMI, but in good health from all other parameters – waist size, body fat, strength, lab values etc etc. BMI is simply unreliable.
And if health professionals are looking at BMI as one of the primary indicators of “good health” then they aren’t fully assessing a patient – they could be overlooking many other health concerns with this focused view of health. Furthermore, they could be putting patient at risk in having them lose weight to get to a certain BMI, but in actuality that could be doing more harm than good. Not only because of the physiological distress and shame that comes with being told to lose weight, but pursuits of weight loss lead to decreasing calorie intake and perhaps macronutrient intake (carbs and fats especially) which can lead to poor health outcomes.
There are so many other factors that determine the quality of our health than BMI. Weight alone is a poor indicator of health! So often, I talk with women both in clinicals and through Nutshell who are on the lower end of a “normal” BMI, yet they aren’t getting their menstrual cycle, their hair is thinning, and they are fighting tooth and nail to maintain that BMI. Then after working together, they regain their menstrual cycle, are eating well and freely, and have thick hair, strong nails, and more energy than ever. And although their weight is at the higher end of the BMI scale, they are the healthiest they have ever been.
BMI shouldn’t even be part of patient assessment. We should look at lab markers. We should look at thyroid function and energy/nutrient intake and sleep patterns and stress levels. And that would help us assess someone’s health. BMI would have no part in the equation.
I’ve seen patients with “overweight” and even “obese” BMI’s who you could say are some of the healthiest people I’ve seen.
But even more than that, the most important point that I want to drive home is that being on the higher end of a “normal BMI” does not mean you are teetering on the edge of unhealthy or that you need to watch your weight. Not at all. Especially with women, our bodies are genetically programmed to be hormonally healthy (including having a healthy menstrual cycle) at a particular weight and even though you want to fight it, you cannot change that. You have a set point where your body will thrive best.
We have to stop fighting it. And instead settle into the body we were given from the very beginning. And walk freely in that. Because this life is way too short to worry about BMIs and fitting into an arbitrary numeric range.
Focus on your energy, how strong you feel, and what your lab values say.
Because the Body Mass Index is bogus.
Faith VanderMolen says
Thanks for sharing Robyn!! Love your posts. So informative but not over my head:)
This is what I strive to feel about my body but I’m scared that I never will…We have to stop fighting it. And instead settle into the body we were given from the very beginning. And walk freely in that.” This seriously just spoke to me. Thank you!
so glad it resonated!
Jacklyn @ Jack's Balancing Act says
I think this is such an important post!! I totally feel for people who aren’t even exactly sure what BMI IS but get caught up in their number when they see charts at the doctor’s and at the gym claiming that it’s reflective of their health. Thanks for shedding light on what the value does and does NOT take into account. I think the message really hit home for a lot of my classmates and I in our first year of dietetics when the prof pointed out at that Arnold Schwarzenegger would be considered obese with the BMI scale! Hope you had a great weekend, Robyn 🙂
Great point about Arnold, ha!
Sarah @ bucketlisttummy says
Great post, especially from a medical professional’s point of view. I definitely agree that people put too strong of a focus on BMI – you need to “eat this” because your BMI is too low, or “avoid eating that” because your BMI is too high. BMI is far from the end all be all and while it can provide some initial indication, it essentially provides nothing else about that person. It is NOT individualized medicine. I like how you say focus on the labs, w/c and muscle mass. Hopefully more RD’s and medical professionals will adopt this view!
Wow, such a great post and I completely agree with you. BMI is something that society puts way too much of an emphasis over. Such an important topic to shed light over, thank you Robyn! <3
Rebecca @ Strength and Sunshine says
Ugh yes!!! Health can not be measured by BMI!
Totally agree! It think looking at weight is a total waste too! Ever since I started lifting and gaining muscle I’ve noticed that the scale sometimes goes up! But that doesn’t mean I’m packing on the weight !
totally agree with weight as well! of course, in underweight patients it carries more weight (no pun intended ha) but as far as being xyz weight to be healthy – that means NOTHING.
I love this and have felt the same way for a long time!! Thanks for the post!
You know I love this post 😉
Thank you for being a breath of fresh air in a world that’s always telling us to strive and change!
thank YOU for reading!
[email protected] says
YESSSS! As a person with a Bachelor’s degree in Food and Human Nutrition I get fed up with the media, press, and other “nutrition professionals” obsessed over the BMI numbers. They are on the leading indicators of good health. Great post, girl!
It’s so misleading! Good to know we’re on the same page 🙂
I had a professor who was an exercise physiologist who would always say that BMI was something made up by the diet industry to make $$$. Thinking about just the people in my life I see how it can be irrelevant.
I also hate the societal assumption that the lower you are on the BMI range the better. So dangerous.
Kate @mindfoodly says
Such a great message. one of the things I have learnt throughout the my recovery from an Eating Disorder (thanks to my wonderful Dietitian) is that BMI’S are absolute bull and really have no indication of someone’s health.
BMI = weight in KILOgrams/height in m squared, not weight in grams. I think BMI is a useful tool when used in collaboration with other indicators of health, not as a standalone number.
rachel @ athletic avocado says
This is perfect! Every single time I go to the doctors and they talk about BMI I just want to tell them that it’s not accurate. Thank you so much for sharing, you said this perfectly!
I absolutely could not agree more! As someone who struggled with her relationship with food and her body for a long time, I so SO believe that our bodies have a natural weight/BMI they’d like to be at, although it can change, and trying to maintain a lower one has only negative consequences. Thank you for this post!
Are lower BMIs indicating someone is underweight as “not big of a deal” as having an above average overweight BMI?
Robyn, I really enjoy the posts that come in my inbox. I get excited for them each and every time because you put things in a way that I get. I have a problem though with myself that I was hoping you could please help me with. It has been going on way too long. I have an eating disorder. I restrict my food. I don’t binge or purge but I do restrict to about 700-800 daily . I am 45, 54″ and my current weight is 107. I am a mother of 5 beautiful gifts. I want to live my life again. I want to incorporate in more food and water (which I find I also restrict because of volume) but have such a deep rooted fear of gaining weight. I used to weigh 180 back in high school and it was not well received by family or friends. I have great faith in God and pray that he will show guidance to me. Robyn, if there is any small thing you can share with me it would be such a blessing. Thank you, ML
Please seek professional help. I suffered from an undiagnosed restrictive eating disorder for 10 years, and because my BMI was not in the underweight category (BMI was 19) and I did not restrict to 300 calories a day (more like 1000 in my case) none of the medical professionals I saw over the years caught it (and I went in for lack of sex drive, never getting my period, and losing hair). I am now in recovery and although it is hard, it is a thousand times better than living life with an eating disorder. It is very unlikely that this is something you can overcome without proper support, and you deserve to live if ed-free.
Thank you, thank you for this post. As a current NP student myself this post was everything I needed to hear today. I, too, feel that looking at the whole person (for more than just a number on a scale) is so vitally important. I find myself feeling frustrated at times when other practitioners talk about telling patients above a certain BMI to lose weight when in actually they are thriving where they are. Obviously if someone is obese and experiencing negative health impacts, than I want to talk about healthy eating and movement and how I can help them improve their health. But so many times assumptions are made based off of a number alone. Your outlook is so refreshing and gave me the encouragement to be the kind of NP I desire to be (one who focuses on the whole person). Thanks again!
Sharing this with all of my clients! I’m a personal trainer and people always want this number. I tell them straight up that it means nothing. Hearing it from an RD as well will help a ton! Thank you for this post!
Thank you for sharing your insight and knowledge on this! I agree with you on BMI not being a very good measure of health. In fact, I read an article recently that said BMI ranges were changed in 2000 so people who were “healthy” one day were suddenly “obese” the next day! Insane.
When I started with you, by BMI standards i was still “within a healthy range”. I”m just over 5’4″, and i was about 120lbs. At that time, my hair was breaking off at the crown, my ribs, spine, and sternum were visible, and as you know i was eating 6 months. Presumably my weight stayed in the optimal range because i naturally have a good bit of muscle which as we all know is more dense and heavier than fat. 🙁 It took ma really long time to accept that it’s mostly a bunch of hooey. According to a BMI chart i could weigh 105lbs and be healthy. uhhh, nope? and, at my body’s set point, which is where i’ve hoovered around for like 6 months now, i’m barely within the upper limit for “healthy range”. Uhhh, what? ha. It’s so arbitrary. even the mathematician that came up with it, is like “hey guys, i never meant for you to use this so broadly.” For me, letting go of the idea of BMI and learning not to weigh myself so much, has made all the difference. I workout 5-7x a week, i try to keep a healthy balance of cardio, strength, and yoga/stretching in there… and really i have a feeling that’s way more healthy than looking at my health in terms of weight divided by height. 🙂
*eating < 1000 calories and hadn't had a period for 6 months.
Melissa a says
Interesting post. I have conflicted feelings about it. I think for many people who may read this blog or the part of our society that strive to be healthy in general, BMI is just a number that has little meaning to it. We put too much pressure on it and our weight. I totally agree with the sentiment.
However, I also think that BMI can be a good number to look at in population health management. I am a consultant for employers who want strategy to improve the health of their workforce. Often an employer will implement a BMI standard (>30, or hip:waist, or an alternative standard) for an incentive. Paired of course with offering programs and resources- like nutritionist, challenges, gym memberships, culture building activists. Sometimes BMI is not a good value to look at if the persons body composition is more muscular so other metrics are looked at. As you know though, high BMI is often seen paired with other elevated biometrics and chronic conditions so giving attention to one value can positively impact others. And BMI, for the good and bad, is one metric that people are more familiar with than triglycerides for example. In this case, I think BMI can be a meaningful number when addressing a population… Of course with individual exceptions.
I would be interested in hearing your thoughts!
Jess @ Keeping It Real Food says
As a fellow RD, I really appreciate this post. There is so much more to take into consideration than BMI! I think it’s one of many factors that we need to look at when discussing overall health. Having those guidelines can be a good jumping-off point, but I do think there tends to be a greater importance placed on it than there should be.
Really nice post–BMI is too often regarded as the only measure of health. A lot of folks don’t realize that calorie restriction even when you’re at a higher BMI can be really bad for you. Thanks for sharing!
Amen to that! I completely agree that BMI is not a clear indication of health. I lift weight and my BMI is teetering on being overweight. However, I do not look overweight or obese…I just have a healthy amount of muscle mass. Great post and will definitely be visiting your blog more often! Glad I found you!
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Nurse Bischof says
I’ve also been told that BMI was developed as a way of measuring the average height-to-weight ratio among entire ethnic/social groups, rather than individuals where things like age and body type can make the number very misleading. I’ve heard, on the individual level, hip-to-waist ratio is a better indicator of personal health.
BMI helps dictate where we go in terms of what kind of plan or program is most appropriate for a patient. The number is not meant to define someone’s health. It’s meant to guide their care where it needs to go.
I’d have to disagree – you’re still then making assumptions about someone’s health based on their BMI, which literature shows, has many inaccuracies. If I guided patient care based on BMI, my care wouldn’t be ethical or evidence based.