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If you’ve been paying attention to our latest podcasts, articles, Q/A’s, and other content then you’ve likely heard us discuss the importance of waist circumference in determining who is a good candidate for weight gain and who could stand to lose a bit of weight.

Waist circumference is a quick, low-cost piece of data with reams of scientific evidence relating the distance around your abdomen with health outcomes like premature death, diabetes, heart disease, stroke risk, etc. While the aforementioned disease processes have many variables contributing to their development and burden, we have large, well-designed studies showing that males and females that have a waist circumferences greater than 40 or 37 inches, respectively, have much higher risks of disease than those who do not.*

That said, there’s a right and a wrong way to do this and we want to make sure you’re doing it correctly. The venerable belly button-or more properly, the umbilicus- is typically the anatomical location suggested to take the waist circumference measurement, but this not actually where much of the waist circumference data described above comes from.

To further complicate things, some large data sets do not even report the procedure used to obtain the waist measurements being studied.

Great.

On the plus side, we have some guidance from the Centers for Disease Control and Prevention (CDC) who commission yearly data collection series, The National Heallth and Nutrition Examination Survey (NHANES). Given that many of the waist circumference studies rely on NHANES data, it is reasonable to use their procedure for our own purposes as well. Here’s the rundown:

  • Use your hand to feel the bony prominences on the front of your hip and find the highest one, theanterior superior iliac spine (ASIS). 
  • Draw a horizontal line to mark ASIS with cosmetic pencil on both sides
  • Place tape measure around waist with the base of the tape measure flush the marked line.
  • Pull the tape snug, but do not compress the skin such that it’s indented by the tape measure
  • Measure to the nearest 0.1cm at the end of expiration.


Practically speaking, I’m aware that most folks are not going to use a cosmetic pencil to measure their waists so I would recommend feeling for the ASIS and then placing the tape around the area just above that bony projection- taking care to keep the tape level to the floor.

So, what does this measurement mean? If it is greater than 40 or 37″ for a male or female, respectively, then I would recommend immediate weight loss via calorie restriction and training modifications (if needed).  Additionally, if someone is within an inch or so of the cut-point, I’ll typically recommend either maintenance level calories if they are relatively untrained, as the waist circumference tends to decrease readily in this population with training. If the person is more advanced and has been gaining weight, I’ll usually reverse the process at this point unless additional contextual factors are present, e.g. a meet very soon.

And there you have it folks, how to measure your waist, what it means, and what to do about it. Thanks for reading!

-Jordan Feigenbaum, MD

*At present, there appears to be some ethnic differences in waist circumference “cut-points”, e.g. men and women of Asian descent appear to have cut points of 37 and 34 inches, respectively. That said, we use the 40 and 37 inch cut points referred to in this section are for all non-Asian men and women as a screening tool.

Join the discussion 21 Comments

  • Marcel says:

    How does one get the funny numbers 40/37 and 37/34 inch? That seems rather arbitrary to me, as if someone just looked at the data and just picked the number for which some error term vanishes.

    I would have expected something related to the body size, e.g. I personally always use a circumference of half the height for men and 40% of the height for women as cut points. Which, given that Asians seem to be a tad smaller, also gives lower numbers. Of course theoretically it should be something non-linear, but a 170cm (66 ish inch) male certainly looks much fatter and carries a lot more bellyfat with 100cm (40 inch) waist than a 2m (80 inch) male, who at this point is probably still quite lean – at least powerlifting lean.

    • Jordan Feigenbaum says:

      By reviewing large data sets and rigorous statistical analysis. Your cut points ARE arbitrary, which is interesting considering your comment. Both examples you posit are at risk.

      • Marcel says:

        Yeah, I pulled my numbers clearly out of my glutes. I just found it curious that the best linear separation of low and high risk groups is a waist circumference levelset and nothing more skew wrt height.

        My reasoning is that waist circumference is mainly used as a proxy for belly fat. But maybe even though a larger person does look less fat with the same waist circumference, it still carries more fat absolutely, and this would mean that the absolute amount of fat mass carried is more relevant to risk factors than the relative amount of fat mass carried. Is that so?

      • Andrew says:

        I think he was giving an example of how he thought that the threshold for waist circumference should be proportional to the height of the person, not that he was suggesting those percentages were the correct thresholds.

        You must be able to understand the confusion since a 5’0″ male with 40″ waist and a 6’2″ male with 40″ waist would likely have very different body compositions.

        Can you speak at all to the reason WHY height is irrelevant? Is that purely based on empirical data for waist size and health outcomes? I assume yes since you mentioned rigorous statistical analysis of large data sets. Did those data sets attempt to differentiate based on height with no statistical differentiation? Were outliers in terms of height excluded from the analysis in order to simplify the recommendation?

        If all of that is irrelevant, are there some theories for the underlying reasons?

        • Jordan Feigenbaum says:

          I wouldn’t necessarily assume that waist should be proportional to height, as there are significant differences between abdominal adipose tissue and subcutaneous adipose tissue in the periphery. Much of the risk attributed to carrying too much fat is secondary to abdominal adipose tissue and its physiology.

          • Andrew says:

            Interesting – the thought had never crossed my mind that general proportionality doesn’t hold as height varies. I wonder if that’s been studied – I’d be curious to know if people in different standard deviations for height have different skeletal proportionality. Must be.

            Anyhow, good stuff. Thanks for the response.

  • Mike says:

    Does the 37/34” recommendation apply to all Asians, or what is typically viewed as East Asian? I ask as someone of South Asian descent. Thanks.

  • Sven says:

    I have the feeling that this article should and could be a lot longer, and should contain much more references to scientific sources and/or resources. Don’t mistake this for not believing you, I just think it would give your article a lot more depth as I don’t have any reason to doubt your knowledge.

  • Andrew.pegg93 says:

    Is there any scientific recommended limit for someone of mixed genetics?

    For example, I am half Chinese (and half European – all over). I have had a doctor in the past take a mid point (i.e. 38.5).

  • Paul says:

    Hi. Thanks for your work and your blog. To help us, your audience, understand the implications of this “40-inch rule,” would you be willing to publish the waist measurements of some of your prominent coaches and/or colleagues who are near or over 40″? And write a few sentences on how you might change their training in order to drop waist measurement and maintain strength? For example, measuring and evaluating someone like Allan Thrall would be super helpful. I may be wrong, but Thrall probably has a waist just over 40″ yet is someone we also listen to and respect as an athlete and coach. Thanks again.

    • bbmedicine says:

      Alan’s is way less than 40″, but I don’t have access to anyone else’s waist data besides my own and my clients. You could just ask a person who’s waist you’re curious about. Might be met with some weird stares, of course.

  • Chris says:

    Hello Jordan,

    thanks for the user manual. I didnt know that and always measured to high. Lets see if that was under- or overestimating…

    I think the data says only waist circumference is ok, but indeed waistt/height is a bit better. https://www.ncbi.nlm.nih.gov/pubmed/18359190

    Of course, its one more step, making it a bit higher threshold. Although imo for somenone who doesnt mind, or for larger study populations, taking into account the height may make sense to get a bit more validity.

    • bbmedicine says:

      That study is 10 years old and much has been done in the interim. Currently there is no singular value that does what we want it to do. That said, BMI and waist circumference together do a good job and other ratios, calculations, etc. don’t do any better.

  • gentlestick says:

    Hello Dr. Feigenbaum,

    I’m having trouble reconciling the waist measuring instructions in the video to the text of the article. I may be misunderstanding, but it seems the video is recommending to measure above the top of the iliac crest. During your demonstration in the video, the tape goes near your belly button, which is similar to where mine goes when I measure from the same place.

    However, the article says to measure above the anterior superior iliac spine (ASIS). According to both Wikipedia (see below) and my potentially mistaken identification on my own body, the ASIS appears to be several centimeters below the top of the iliac crest. Could you clarify from which location is the correct place to measure? Thank you.

    https://en.wikipedia.org/wiki/Anterior_superior_iliac_spine

    • bbmedicine says:

      The position of the umbilicus (belly button) is irrelevant to the waist circumference measurement and only adds to the confusion. The article and the video are both correct, as you should measure above the ASIS at the top of the iliac crest.

  • gentlestick says:

    Forgive me, but as a lay person with zero background in anatomy, I’m afraid I’m still very confused by your instructions. I’m probably misunderstanding something, but let me be more specific about what is confusing me:

    The article states:

    “Use your hand to feel the bony prominences on the front of your hip and find the highest one, the anterior superior iliac spine (ASIS).
    Draw a horizontal line to mark ASIS with cosmetic pencil on both sides.
    Place tape measure around waist with the base of the tape measure flush the marked line.”

    and also:

    “I would recommend feeling for the ASIS and then placing the tape around the area just above that bony projection…”

    However, the horizontal mark depicted in Exhibit 3-9 does not appear to be at or even “just above” the location of the ASIS based on my understanding of where the ASIS is located. Using the following image (https://www.wesnorman.com/Images/pelvislateral.jpg) for example as a guidepost, the horizontal mark in Exhibit 3-9 appears to be at the top of the Iliac crest and NOT at or even “just above” the ASIS?

    Furthermore, the narration of the video, beginning at 5:10, says:

    “At the superior margin of the iliac crest, that’s the highest point that you can palpate…that’s where the bottom of the tape measure will be.”

    Again, based on my possibly incorrect understanding, and based on the images that I’ve found and linked in my two comments, placing the tape measure directly above the ASIS and directly above the superior margin of the iliac crest would appear to place the tape measure at two different locations that are several centimeters apart.

    I look forward to your clarifying my misunderstanding! Thanks.

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