The Edit · Founder Insights
What Over 1000 Healthspan Audits Reveal About Ageing Well
Over 1000 people have taken Catalyst's Healthspan Audit. Here is what the data says predicts ageing well, and why most diets get it backwards.
Over 1000 people in Singapore have taken the Catalyst Healthspan Audit, and the data keeps saying the same thing: age, body fat, and muscle predict how well someone ages more reliably than anything else we measure, and muscle is the one people manage worst.
TL;DR
- Across over 1000 Healthspan Audits, age, body fat, and muscle are the three strongest predictors of how well someone ages.
- 66.2% of adults in Singapore do not meet the minimum strength-training guideline of 2 sessions a week.
- When people lose weight through dieting alone, roughly 14% to 26% of that loss is muscle, not fat.
- Adding resistance training to a weight-loss diet significantly protects muscle while still increasing fat loss.
- Losing weight without training is not the same as ageing well. Often it moves you the wrong way.
What the audit actually measures
The Healthspan Audit is a free, 3-minute self-assessment built to put a number on the four things that predict long-term function: body composition, cardiorespiratory fitness, stability, and strength. Over 1000 people in Singapore have taken it. Reviewing that data, one pattern shows up more consistently than any other combination of inputs: age, body fat, and muscle move the score more than anything else.
The four pillars are not arbitrary. Body composition and cardiorespiratory fitness show up in almost every population study of healthy ageing. Stability predicts fall risk directly. Strength predicts almost everything else, including how long someone stays functionally independent. Age is the one variable nobody can train against, which is exactly why the other three matter more with each year that passes.
The score itself runs 0 to 10, the same scale we use for the in-studio assessment. It is not designed to diagnose anything. It is designed to show, in one honest number, roughly where someone stands before symptoms force the issue.
In practice, that shows up as something ordinary and easy to miss. Not a dramatic health event, just a slower recovery from a flight, a heavier feeling on the stairs at the MRT, a grip that used to open a jar without thinking twice. None of that shows up on a bathroom scale. It shows up in the muscle number.
That is not a surprising result on its own. What is worth stopping on is which of the three people are worst positioned on, and why.
The pillar people manage worst
Dr Luqman Haris, our co-founder, reviews this data closely, and the same gap shows up constantly: strength is the pillar people arrive furthest behind on. Not because strength training is complicated. Because most people are not doing enough of it for it to count.
That is not just a studio impression. In Singapore's most recent national health survey, only 33.8% of residents aged 18 to 74 reported meeting the guideline of at least two muscle-strengthening sessions a week, meaning two in three adults fall short (National Population Health Survey 2020). It gets worse with age: only 25.5% of adults aged 60 to 74 meet the guideline.
Ask most people how often they train against resistance specifically, not cardio, not walking, and the honest answer is usually once a week, if that. That matches what shows up in the audit responses, and it matches the national picture below almost exactly.
The diet that costs you the wrong tissue
Here is the part most diets never mention. When you lose weight through calorie restriction alone, without resistance training, a meaningful share of what comes off is muscle, not fat. A 2024 analysis modelling caloric-restriction-induced weight loss found that roughly 14% to 26% of the weight lost this way is skeletal muscle, depending on sex and starting body composition (Heymsfield et al., 2024).
Add resistance training to the same diet and the picture changes. A 2025 systematic review and meta-analysis of 25 randomised controlled trials found that combining resistance exercise with dietary weight loss significantly reduced the amount of fat-free mass lost, while also increasing the amount of fat lost, compared with diet alone (Binmahfoz et al., 2025).
The scale cannot tell you what you actually lost. Only the composition can.
The mechanism is not complicated. In a calorie deficit, the body breaks down tissue for energy, and without a strong enough signal telling it to protect muscle, it takes whichever tissue is easiest, not whichever tissue is most valuable. Resistance training supplies that signal. It tells the body specifically which tissue is still being used and needs to stay. Adequate protein reinforces the same signal by supplying the raw material muscle needs to repair itself between sessions.
This is why a lower number on the scale is not the same as ageing well. It depends entirely on what came off.
What this looks like in Singapore
Put the two findings together and the local picture is stark. Two in three adults in Singapore are not training their muscle enough to protect it. At the same time, any weight-loss effort undertaken without resistance training is likely eating into the same tissue that guideline exists to protect.
Muscle is not only about strength. A 2014 analysis of the NHANES III cohort found that older adults with higher relative muscle mass had a meaningfully lower risk of all-cause mortality than those with less, independent of body fat (Srikanthan and Karlamangla, 2014). Muscle mass tracked with survival, not just performance.
For the desk-based professionals we see most in Singapore's CBD, this compounds quietly. Long hours at a desk already reduce the incidental movement that used to substitute for deliberate training. Add an aggressive diet on top, without resistance work, and the two problems reinforce each other: less muscle from inactivity, then more muscle lost again through the diet.
This matters most for people in their 40s and beyond, not because younger people are exempt, but because the compounding effect is further along by then. Someone who starts paying attention to this in their 40s is on a genuinely different trajectory into their 60s and 70s than someone who only starts once a health scare forces the question.
That is the connection the Healthspan Audit is built to surface early, well before it shows up as a fall, a fracture, or a diagnosis.
What to do instead
None of this makes dieting the enemy. It means the method matters more than the number on the scale. If you are losing weight, the goal is to lose fat and keep the muscle, not to lose weight generally.
Practically, that means resistance training at least twice a week, as the main event rather than an add-on to cardio, alongside adequate protein. In practice that is 2 to 3 sessions a week and protein in the range of 1.2 to 1.6 grams per kilogram of bodyweight a day, adjusted to activity level and goals. Neither number is exotic. Both are simply higher than what most people are currently doing. I have written the fuller breakdown of what that looks like after 40 in body recomposition after 40. If you are managing muscle loss on a GLP-1 medication specifically, the mechanism is the same but the stakes are higher, and I cover that in keeping your muscle on a GLP-1.
The starting point, either way, is knowing where you actually stand. That is what the audit is for. I built it because I kept having the same conversation in the studio: someone proud of a number on the scale, and an assessment telling a different story underneath it. The audit will not replace that conversation. It just gives more people a way to start having it earlier, on their own terms, before the stakes get higher.
Frequently asked questions
Q. How much muscle do you actually lose when dieting without exercise?
Research modelling caloric-restriction-induced weight loss estimates that roughly 14% to 26% of the weight lost through diet alone is skeletal muscle, varying by sex and starting body composition. Adding resistance training substantially reduces that share.
Q. Do I need to lift weights if I am just trying to lose weight?
If the goal is to lose fat rather than lose weight generally, yes. Resistance training preserves the muscle a calorie deficit would otherwise take, and studies combining diet with resistance training show greater fat loss, not less, than diet alone.
Q. What share of adults in Singapore meet the strength training guideline?
According to Singapore's National Population Health Survey 2020, only 33.8% of residents aged 18 to 74 reported meeting the guideline of at least two muscle-strengthening sessions a week. The share is lower among adults aged 60 to 74.
Q. Is the Healthspan Audit the same as the in-studio assessment?
No. The Healthspan Audit is a free, 3-minute self-reported online estimate. The in-studio 4-Pillar Healthspan Assessment measures the same four pillars on real instruments over 60 minutes and is more precise. The audit is a first read, not a replacement.
Q. Why does muscle mass matter for ageing, not just strength?
A cohort study following older adults found that those with higher relative muscle mass had a meaningfully lower risk of all-cause mortality over the follow-up period than those with less, independent of strength alone. Muscle appears to matter for survival, not only performance.
Citations
Heymsfield SB, Yang S, McCarthy C, Brown JB, Martin CK, Redman LM, Ravussin E, Shen W, Muller MJ, Bosy-Westphal A (2024). Proportion of caloric restriction-induced weight loss as skeletal muscle. Obesity (Silver Spring), 32(1), 32-40. pubmed.ncbi.nlm.nih.gov/37807154
Binmahfoz A, Dighriri A, Gray C, Gray SR (2025). Effect of resistance exercise on body composition, muscle strength and cardiometabolic health during dietary weight loss in people living with overweight or obesity: a systematic review and meta-analysis. BMJ Open Sport & Exercise Medicine, 11(3), e002363. pubmed.ncbi.nlm.nih.gov/40909191
Ministry of Health, Singapore and Health Promotion Board (2021). National Population Health Survey 2020. Epidemiology and Disease Control Division. National Population Health Survey 2020 report (PDF) isomer-user-content.by.gov.sg/3/4bf349c8-25d6-4eb8-bf02-af769321458f/nphs-2020-survey-report.pdf
Srikanthan P, Karlamangla AS (2014). Muscle mass index as a predictor of longevity in older adults. American Journal of Medicine, 127(6), 547-553. pubmed.ncbi.nlm.nih.gov/24561114
