Thanks for bearing with me as we trawl through the seemingly endless Lancet Commission on ‘clinical o*esity’. Click here to read Parts 1 and 2.Please be advised that the following post contains multiple meat-puns, which may be triggering to vegetarians/the squeamish.
Akin to the elaborate grading systems seen in Wagyu beef, BMI alone is now deemed insufficient: they want additional measurements to sleuth human marbling fatness. This is because the BMI has done a spectacularly awful job of detecting it.
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The Bullsh*t Measurement Index (BMI)
The entire field of o*esity research is based on BMI, which is not a disease but an equation- (weight divided by height squared)- invented by a 17th century statistician. The story of the BMI’s rise to prominence is replete with eugenics-loving white men bearing serious grudges against fat people. The BMI was intended for use in population statistics, but decades of research correlating BMI categories with actual diseases (particularly diabetes) has resulted in widespread acceptance that ‘o*esity’ (BMI >30) itself is a proxy for poor health. In spite of no evidence of a causal link between high BMI and the diseases it’s ‘associated’ with, the unusual persistence of the o*esity field is largely due to the influence and manipulation of the weight loss industry, who have diligently funded o*esity researchers and ‘societies’ and disease-mongering research, drumming up ever-increasing hysteria about the ‘o*esity epidemic.’
In spite of concerted efforts to be seen as legitimate science- and not just a front for the weight loss industry- the field has grappled with a fundamental problem: BMI is a terrible predictor of individual health. High quality data shows that 1 in 3 people with BMIs > 30 were in good metabolic health, while 1 in 3 with BMIs < 25 experienced metabolic health issues. The Lancet authors had an interesting take why the BMI’s inaccuracy was problematic:
‘BMI can overdiagnose o*esity; famous examples of such misclassifications are legendary boxers and US National Football League quarterbacks.’
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The reference provided for this statement was a Scientific American article written by ‘Get Fit Guy’ Brock Armstrong,’ a Youtuber- which didn’t even mention boxers.
Good Quality Research is ‘Biased’
Echoing concerns raised by weight-inclusive advocates and researchers, the Lancet authors admitted that when confounding factors such as smoking, other diseases, weight cycling, overall diet quality, and physical activity levels are taken into account, the relationship between BMI and adverse health outcomes essentially vanishes. Factors like age, sociodemographic status and experiences of weight stigma weren’t mentioned, but these are also important mediators in the relationship between BMI and health.
Identifying and controlling for confounding variables is standard scientific practice. This would have been a good time for the Lancet authors to call for the adoption of high quality data, eliminating the widespread use of confounded information across their field.Instead they doubled down on the use of said confounded BMI research, in a befuddling claim that:
‘eliminating individuals from the analysis on the basis of such factors can plausibly create biases.’
I checked the 2 references provided for this- what kind of ‘biases’ could possibly be introduced from using clean data? The first paper actually recommended in favour of BMI data controlling for gender and race, and the second didn’t even discuss confounding variables in BMI research. It seems that the ‘bias’ the Commission authors are worried about may simply be the facts: once confounds are taken into account, the BMI’s irrelevance is exposed.
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Assessing ‘Excess Adiposity’
After gaslighting the reader by claiming that quality controlled BMI research was biased, the paper moved on to suggest that the best way forward would be to keep it, and add more body measurements ‘such as waist circumference or body fat percentage’ to ensure the detection of ‘excess adiposity’ rather than muscle.
The justification for this was the relevance of the ‘location and distribution’ of fat around the body, reminiscent of the wagyu beef grading endocrinologists’ ABCD model. This differentiated between ‘good’ fat around butts and thighs, and ‘bad’ fat within the abdomen and around and within organs, the apparent ‘smoking gun’ in the relationship between weight and poor health outcomes.
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The problem is, it’s very difficult to accurately assess how much fat is lurking inside the middle of our bodies. Short of carving into people’s midsections, we simply can’t know for sure.**
The Lancet recommended a new process, including:
● At least one measurement of body size (waist circumference, waist-to-hip ratio or waist-to-height ratio) in addition to BMI
● At least two measurements of body size (waist circumference, waist-to-hip ratio or waist-to-height ratio) regardless of BMI
● Direct body fat measurement (such as by a bone densitometry scan or DEXA) regardless of BMI
● In people with very high BMI (ie, >40 kg/m2), however, excess adiposity can pragmatically be assumed, and no further confirmation is required????.
(italics and angry emoji added)
There’s no reference to a scientific paper linking people with a BMI> 40 as being definitively #toofat, or information on how the Commissioners came to this ‘pragmatic’ decision. It seemed their concern about miscategorizing athletes didn’t extend to WWF wrestlers like Rikishi, or Olympic Judo champion Ricardo Blas Jr, both of whom could run rings around these dusty academics.
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In Rubino’s system, people with a BMI>25 (but below 40) would now require ‘at least 1’ additional body measurement to confirm ‘excess’ fat. Anyone suspected of being #toofat would be subjected to ‘at least 2 body measurements,’ – regardless of BMI, opening up a whole new market group of people to body scrutiny.
Let’s take a closer look at their additional body measurements:
Waist Circumference, Waist-to-Hip & Waist-to-Height Ratios:
An infographic accompanying the Commission report recommended cutoffs for waist circumference >102cm for men and >88cm for women, a waist-to-hip ratio >.90 for men and >.85 for women, and a waist-to-height ratio >.50 ‘for all.’ If you’re above these measures, you’re officially #toofat, and will be sent down the production line for assessment of ‘clinical o*esity.’
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The reference provided for these cut-off points was a WHO Expert consultation report from 2008, which was an enlightening read. Rather than providing a comprehensive, evidence-based list of cut offs for global use, they concluded that there were:
‘too many unresolved issues for the consultation to determine whether this process would be useful.’
These ‘unresolved issues’ were the fact that all 3 measures were confounded by sex differences, age-related body composition changes, and ethnicity. The WHO paper discussed these issues in depth, highlighting relevant facts about fat which were ignored by the Lancet Commissioners. Let’s take a closer look at #fatfacts:
Aging and BMI:
Body weight is not fixed: longitudinal research shows that BMI naturally increases with age. The WHO paper included three large American studies, which clearly showed BMI increases until the seventh or eighth decade:
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It also included this longitudinal BMI data from a Japanese cohort:
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And here’s some recent Australian data which also demonstrates the increase in average body weight over our lifespan:
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We need to face it: body weight increases as we age are normal- not a ‘disease process.’
Aging, Waist Circumference & Waist-Hip Ratio :
Waist circumference also increases with age. The WHO paper presented the 1999-2000 NHANES dataset, where the average waist circumference of males aged 20-29 was 92 cm. This increased to 105.4cm in 60–69-year old men. Women aged 20-29 had an average waist circumference of 86cm, increasing to 97cm for 60–69 year olds.
Here’s the Australian data showing the same trend:
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Waist-hip ratio also changes with age, demonstrated in the Baltimore Longitudinal Study of Aging for both males and females.
Waist circumference and waist-hip ratio increases happen across all BMI categories, and are a normal part of aging – not evidence of ‘pathology.’
Aging and Fat Distribution:
The distribution of fat around our bodies also changes with age. The WHO report stated:
‘ageing is associated with substantial redistribution of fat tissue among depots (Cartwright et al., 2007). From late middle age until the 80s or later, there is a decline in the volume of subcutaneous fat, and a redistribution of fat from subcutaneous to visceral depots. This age‐associated decline in the size of adipose depots is accompanied by the accumulation of fat outside adipose tissue (in muscle, liver and bone marrow), and loss of lean body mass.’
As we get older, subcutaneous fat- stored just under our skin, often in our butts and thighs- reduces, while visceral fat- which is stored in our abdomen and around our organs- dramatically increases. The reason for such changes are complex, including age-related loss of muscle mass and hormonal changes.
Sex Differences in Body Composition:
The WHO report described how due to sex hormones, females have more body fat than males, which is distributed differently. Men tend to have ‘a relatively greater central distribution of fat’. For women across the lifespan, body fat distribution is further impacted by events such as pregnancy and menopause. Across all BMI categories, pregnancy alters body fat distribution, from lower parts of the body to more ‘central’ locations. Menopause also gifts women with increased fat mass and visceral fat, thanks to reductions in oestrogen.
Body Composition and Ethnicity:
The WHO paper acknowledged that the bulk of research on waist circumference, waist-to-hip and waist-height ratios was conducted on (surprise surprise) white Europeans. Based on the small number of studies exploring these measures in other ethnicities, they concluded that:
‘Compared to Europeans, Asian populations have greater visceral adipose tissue, and African populations and, possibly, Pacific Islanders have less visceral adipose tissue or percentage of body fat at any given waist circumference.’
Although some progress has been made in controlling for ethnicity in these body measures, the bulk of o*esity research linking them to actual health risks is still conducted on white populations. The WHO concluded that:
‘given that the objective is to predict disease risk, drawing conclusions about cut‐offs solely on the basis of observed risks does not seem appropriate.’
Body Fat Percentage
The Lancet paper also recommended body fat percentage to detect ‘excess fatness,’ measured by either Dual X-Ray Absorptiometry (DXA), Bioelectrical Impedance Analysis (BIA), or the use of medieval torture devices such as calipers.
No data regarding the reliability of these methods was presented, so I Googled. If you don’t mind a little radiation DXA’s are considered the ‘gold standard,’ and are incidentally quite effective in grading steaks. On the downside, they require high tech radiography equipment, and are expensive.
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BIA yields dodgy data, especially for larger bodied people, and its validity has been questioned. Calipers are a scientific embarrassment which should exist only in medieval torture exhibits.
The Lancet Appendix provided body fat % thresholds for men and women, but warned that cut-offs vary according to which method was used, plus there’s still the problem of confounded data, particularly with age and ethnicity.
Sloppy Science
Rubino’s Commission recommended that ‘thresholds for age, sex and ethnicity or country should be used for all anthropomorphic measures,’directing readers to their supplemental index for ‘ethnicity-specific and paediatric thresholds.’
But the index provided no paediatric data. None of the thresholds controlled for age. Cut-offs for BMI and waist circumference for 14 different ethnicities were provided, but were still confounded by age.
It’s clear that the study of secondary anthropomorphic measures is in just as bad shape- if not worse- than the BMI.
Let’s cut the crap: the data on body size and health is inextricably entangled with aging, sex, and ethnicity. Instead of fixing fundamental flaws, the o*esity field keeps playing games—shifting goalposts and pretending fat exists in a vacuum.
The sloppiness of the Lancet Commission- quoting gym-bros, forgetting paediatric data- shows that this group couldn’t run a Bunnings sausage sizzle, and certainly shouldn’t be determining the diagnosis of being allegedly #toofat.
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A Waist of Time
Collecting waist and/or hip measurements requires health professionals to perform intimate procedures: for waist circumference, the WHO instructs them to locate the midpoint ‘between the lowest rib and the top of the iliac crest,’ and then measure. But they also said waist measurements could be taken at the level of the belly button, and still others at ‘minimal waist level,’ adding room for yet more confusion.
Calipers deserve a special place in hell mention- literally ‘pinching’ fat across multiple body parts. I can’t think of anything worse. All of these ‘fat-finding’ procedures put people’s bodies on show in a vulnerable and potentially very upsetting experience.
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Even if there was an established body of high quality, confound-controlled data to show that these procedures reliably elicit robust measures of too-fatness, would they meaningfully add to good health care?
A 2020 paper from the International Atherosclerosis Society (IAS) and International Chair on Cardiometabolic Risk (ICCR) Working Group on Visceral O*esity found that waist circumference was useful at a population level. But in clinical practice, adding waist circumference was no more predictive than using easily available data such as age, gender, race, and standardised cardiovascular risk assessment (ie, actual health care), skewering the Lancet’s position that measures of ‘excess adiposity’ are needed.
Additional fat-finding is a waist of time. The o*esity field’s obsession with ‘excess adiposity’ is terrific for expanding their market, but they’re merely encouraging bad science. If you’re faced with a tape-measure wielding health professional, don’t mince words: stand up for yourself, and demand actual health care!
Right, it’s off to the isolation tank for me. I’ll be back to discuss the Lancet finale- their elaborate ‘clinical o*esity’ criteria- very soon. Thanks for bearing with me- and apologies if I’ve put you off steak!
Louise x
*’Adiposity’ is a fancy name for fat cells.
**It’s only a matter of time before bariatric surgeons suggest exploratory surgery to ‘assess excess adiposity’????.
If you are struggling with issues relating to food, your body, exercise, or with an eating disorder, I can help. I have offices at Flourish Kirribilli in Sydney, and am also available for online appointments. If you’re a health professional looking for help with providing weight-inclusive care I also provide clinical supervision, and my books are currently open.
