Singapore uses a BMI of 23 for overweight and 27.5 for obesity, not 25 and 30, because research conducted substantially in Singapore found that the same BMI carries more body fat, and more risk, in this population. In one study of 291 Singaporean adults, a Caucasian-derived equation under-predicted body fat by 2.7 to 5.6 percentage points (Deurenberg-Yap 2000).
BMI: weight divided by height squared. A ratio designed as a population screening tool, which assumes a consistent relationship between that ratio and body fat. That assumption is where the problem sits.
The measurement that started it
BMI does not measure fat. It measures the relationship between mass and height, and it is used as a proxy for fat on the assumption that the relationship holds. In Singapore, researchers tested that assumption directly.
Using a four-compartment reference model — the most rigorous body-composition method available — in 291 Singaporean Chinese, Malay and Indian adults, a prediction equation derived from Caucasian populations under-predicted body-fat percentage by 2.7 to 5.6 percentage points (Deurenberg-Yap 2000).
Put the other way round: to reach the body-fat percentage that a Caucasian carries at a BMI of 30, the equivalent BMI was about 27 kg/m² for Chinese and Malay participants and about 26 for Indian participants.
The differences ran by ethnicity within Singapore too. Indian participants showed the highest body-fat percentage at equivalent BMI, Chinese participants the lowest. So this is not one adjustment applied to "Asians" as a bloc — it is a set of different relationships, which is part of why the guideline settles on a single practical threshold rather than trying to encode all of them.
A more recent DXA-based study of Singaporean adults reached the same conclusion by a different route: body-fat percentage was higher than the same BMI, age and sex would predict in Caucasian reference populations (Chen 2021).
The risk that follows
More fat at a given BMI would be an academic finding if it did not track with anything. It does.
In a Singapore population study of 4,723 adults, at a BMI of 22–24 and waist circumferences of 75–80 cm in women and 80–85 cm in men, cardiovascular risk-factor prevalence ran between 41% and 81%, with odds ratios of 1.97 to 4.38 against reference (Deurenberg-Yap 2002). At equivalent body fat, Singaporean BMI ran about 3 kg/m² lower than Caucasian.
A BMI of 22 to 24 sits comfortably inside the international "normal" band. In this population, a substantial share of people in that band already had cardiovascular risk factors.
That is the finding the thresholds exist to catch.
What WHO actually did
This gets misreported often enough to be worth stating precisely.
A WHO expert consultation reviewed the Asian data and found that health risk rises at BMI levels below the standard international overweight threshold — an observed-risk range across Asian populations of 22–25 kg/m², and a high-risk range of 26–31 (WHO 2004).
What it did not do was lower the international cut-offs. It explicitly retained the existing global classification and proposed additional public-health action points alongside it, at 23.0, 27.5, 32.5 and 37.5 kg/m².
So "WHO changed BMI for Asians" is wrong. WHO kept the international classification and added a second set of trigger points for countries to use. Singapore adopted the relevant ones: its clinical practice guidelines set overweight at 23.0 and obesity at 27.5 (HPB-MOH 2016), alongside waist-circumference action points of above 90 cm for men and 80 cm for women.
What is a normal BMI for seniors?
A normal BMI for seniors in Singapore is the same as for every other adult, 18.5 to 22.9, because the national guideline gives one set of adult bands and does not split them by age (HPB-MOH 2016). Studies of older adults read a low BMI with more caution. In a 2014 analysis of 32 studies and 197,940 adults aged 65 and over, death risk from any cause was 12% higher at a BMI of 21.0 to 21.9 and 19% higher at 20.0 to 20.9 than at 23.0 to 23.9, and only began to rise above a BMI of 33 (Winter 2014).
A Singapore study points the same way. The Singapore Longitudinal Ageing Studies followed 2,605 Chinese adults aged 55 and over from 2003 to 2011: deaths from any cause were lowest at a BMI of 23.0 to 24.9, and among those aged 65 and over the overweight and obese groups did not have significantly more deaths from any cause, although the overweight-obese group had more deaths from heart disease and stroke (Ng 2017). Both are observational studies of death rates, not a guideline, so they show an association, not a target, and neither changes Singapore's bands.
What is the ideal weight for a 70-year-old woman?
There is no single ideal weight for a 70-year-old woman: Singapore's guideline works in BMI bands, not weights, and gives her the same normal band as any adult, 18.5 to 22.9, with a waist above 80 cm as the action point for women (HPB-MOH 2016). The weight that falls in that band depends on her height, which the BMI chart for Singapore sets out from 145 to 190 cm. In the 2014 analysis of older adults, death risk was higher below a BMI of 23, and its authors advise watching the weight of older people in that range and dealing promptly with any cause of weight loss that can be addressed (Winter 2014), so unplanned weight loss at 70 is worth raising with a doctor.
What it does not tell you
Three things, and the third is the one people most often get wrong.
It is still BMI. A lower threshold does not fix the underlying limitation — BMI still cannot distinguish muscle from fat, and it still says nothing about where fat is carried. Lowering the number makes the screen more sensitive in this population; it does not make it a measure of composition. We cover the alternatives in body fat vs BMI vs weight.
There is no matching body-fat threshold. Singapore publishes BMI and waist-circumference figures. Neither HPB nor MOH publishes a body-fat-percentage cut-off, and a 2021 Singapore study reports the same absence of an Asian consensus cut-off (Chen 2021). If you are shown a body-fat percentage presented as a Singapore standard, it is not one.
A threshold is not an eligibility rule. Whether any particular treatment is appropriate for a particular person is a clinical assessment, and it takes account of considerably more than one ratio. A number crossing a line is a reason for a conversation, not the outcome of one.
At GetLean, the programme is designed to end, and our philosophy is that the composition is the goal and the weight is a by-product. The Asian threshold research is, in a sense, the same argument made at national scale: the number on its own was hiding something, and looking at what bodies are actually made of changed the answer. The plan for coming off is the GetLean GLP-1 Taper Plan: after hitting your goal weight with the right nutrition and exercise habits built, the dose is stepped down at Dr Quek's monthly reviews towards your lowest effective dose and, where clinically appropriate, off the medication.
Individual circumstances vary, and what any of this means for you is a question for a doctor who has assessed you.
Common questions
Why does Singapore use a BMI of 27.5 instead of 30?
Because risk appears at lower body sizes here. A WHO expert consultation found risk rising below the standard threshold in Asian populations and proposed additional action points at 23.0 and 27.5 kg/m² (WHO 2004), which Singapore's guidelines adopt (HPB-MOH 2016).
Do Asians have more body fat at the same BMI?
In Singaporeans, yes. A Caucasian-derived prediction equation under-predicted body-fat percentage by 2.7 to 5.6 percentage points in a four-compartment study of 291 adults (Deurenberg-Yap 2000).
Is the difference the same for all ethnic groups in Singapore?
No. In that study Indian participants showed the highest body-fat percentage at equivalent BMI and Chinese participants the lowest, with matching thresholds of about 26 and 27 kg/m² respectively (Deurenberg-Yap 2000).
Did WHO lower the international BMI cut-offs?
No. The consultation explicitly retained the existing international classification and added supplementary public-health action points alongside it (WHO 2004).
Is a BMI of 24 a problem in Singapore?
It is worth looking at rather than dismissing. Cardiovascular risk-factor prevalence ran 41-81% at BMI 22-24 in a Singapore population study (Deurenberg-Yap 2002). What it means for you is a clinical question.