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Hey everyone, Mikki here. You're listening to Mini Mikkipedia on a Monday. And today I want to chat about a topic which I have conversations about with clients all of the time. And that is where should my body fat percentage be? And this episode was sparked somewhat by a couple of chasing clarity podcast episodes. And you guys will know that my mate Brandon Nacruz does an excellent job of distilling

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the research and on one of the more recent episodes, him and his mate, Jeff, were chatting about it just in the context of fat loss. You know, where should someone aim in terms of their body fat percentage? And then last year, just over a year ago, Brandon did quite a deep dive into this question, whether we are in fact just under-muscled or are we over fat? And I really wanted to dive a little bit deeper into the research, if you like, and give you my understanding.

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of it because it's a question that I talk to a lot of clients about. When they're on this fat loss journey or when they're wanting to maintain, they had this particular number of, is where my body fat percentage is, what should it be? And what I will start off by saying is that there isn't a universal consensus. And it is worth noting that because so often a lot of the research looks at body fat percentage norms in relation to cardiovascular disease, risk, diabetes,

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risk and other cardio metabolic outcomes. But then on the flip side, you've got the fitness and the physique space, whereby that whole sport is defined on levels of body fat percentage. And so, you know, what does this mean for the average healthy individual who really just wants to look good and perform great and be at lowest possible health risk? So I want to go through some of the evidence with you today and we're going to cover off

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why body fat matters for health in the first place. Surprisingly, this is contentious. You should see the things that I see on Instagram about this. What we actually know about healthy ranges across different ages and populations and how best to measure it because it turns out that, huh, that's even more complicated than most people realize. So let's get into it. Let's first go through why does body fat matter? Because if you understand the mechanisms,

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the numbers can make a lot more sense. We used to think fat tissue was dead weight, and it isn't. It is not just passive storage. Fat itself is metabolically active endocrine organ. It produces hormones, including leptin, which regulates hunger, and adiponectin, which plays a role in insulin sensitivity. It contributes to inflammation. It communicates with your liver, your pancreas, your cardiovascular system, and all of this is fine and functional.

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because we need body fat. provides energy, storage, thermal insulation, mechanical cushioning for organs, and it's essential for reproductive function, particularly in women. However, the problems arise when we carry fat in excess, and particularly when that fat accumulates in specific places, i.e. the trunk, the abdomen, visceral fat. And so this does bring us to this important distinction that doesn't always get talked about enough, but

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which I talk about quite a bit because I'm, you know, it's in my wheelhouse if you like, the difference between subcutaneous fat and visceral fat. And I know that you've heard me say this multiple times, but for the context of this discussion, it is worth repeating. Subcutaneous fat sits just beneath the skin. It's the fat that you can pinch. It's metabolically active, but relatively benign in moderate amounts. Visceral fat, on the other hand, sits deep in the abdominal cavity surrounding your organs.

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And this is the stuff that really drives cardiometabolic risk. Visceral fat is more metabolically disruptive, so it contributes to insulin resistance, raises blood pressure, drives systemic inflammation, and is closely linked to the development of metabolic syndrome, type 2 diabetes, and cardiovascular disease. And this is why waist circumference as a rough proxy for visceral fat is a useful clinical measure.

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It's also why two people with the same BMI can have very different health outcomes. Someone with the same body weight but more visceral fat relative to subcutaneous fat is at meaningfully higher risk. So what happens when we carry too much body fat overall? So the research is pretty clear m and sobering actually. Excess adiposity, carrying more body fat than our physiology can manage well,

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increases risk for a substantial list of conditions. Type 2 diabetes, heart disease, hypertension, metabolic syndrome, certain cancers including breast, colon and prostate, osteoarthritis, sleep apnea, non-alcoholic fatty liver disease, known as metabolic associated fatty liver disease, fertility issues in both men and women, and mental health challenges including depression and body image difficulties. So,

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That is not a trivial list. One study looking specifically at body fat percentage thresholds found that once men exceeded around 26 % body fat and women exceeded around 37 % body fat, the odds of developing cardiovascular risk factors were two to four times higher than for people below those thresholds. For men specifically, the odds of developing hypertension and diabetes were more than two and a half times above that cutoff.

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So the relationship between excess body fat and poor health outcomes is real. It's consistent across the literature and I'd say that it isn't subtle. However, I do want to address something directly because I think it would be a disservice to talk about body fat and health without acknowledging the cultural context we're operating in. There is a movement, the Health at Every Size movement, which has genuinely done important work. It has challenged weight stigma.

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which is real and causes real harm. It is pushed back against the damaging messaging that ties people's worth to their body size. It has highlighted that healthcare providers have historically given poorer care to larger bodied patients, and that's a problem that needs addressing. And it has correctly noted that the pursuit of weight loss, particularly through restrictive dieting, can sometimes cause its own harms. So all of that is absolutely worth acknowledging and taking seriously.

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But I do want to be honest with you about what the evidence does and doesn't support. Health at every size is a literal physiological claim that body fat level has no bearing on health outcomes isn't supported by the research. The evidence that excess body fat increases risk for a range of chronic diseases is substantial, replicated across huge population studies and not seriously contested in the scientific literature. There's a concept called metabolically healthy obesity.

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where someone has a BMI in the obese range, but doesn't yet show the metabolic complications we'd expect. And again, that's real. Its prevalence is estimated at somewhere between 10 and 30 % of people with obesity. But the research indicates it's 10, it tends to be this transient state. So over time, the metabolic consequences tend to emerge. So it's not a stable or permanent condition for most people and

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often you see it's actually tied back to activity levels. So the more active you are, it's a bit of a buffer for this excess body fat. However, my position, and I think the position that the evidence supports, is that we can and should fight weight stigma, of course. We should treat everyone with dignity and respect, regardless of body size. And we should challenge the type of diet culture that makes someone question their worth, absolutely.

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And we can simultaneously acknowledge that body composition does matter for health and that excess body fat carries genuine risk. These aren't contradictory positions. They just require holding a bit of nuance if you like. And the goal isn't to be skinny. It's not about getting a six pack. It's a body composition that supports your long-term health and function. And these are two very different things. Right. So with that context, what does the research actually tell us about healthy body fat ranges?

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As I said, there is no single universally accepted number and no official cutoff from the World Health Organization or the NIH or any sort of European classification. There's no one number that all bodies support. What we have are ranges derived from population studies, primarily using methods like DEXA or bioelectrical impedance that correlate with lower morbidity and mortality. And those ranges can

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vary meaningfully depending on sex, age, and ethnicity. So let's start with a broad consensus for adults. For adult men, most large studies report a healthy body fat percentage somewhere in the range of 8 to 21%. The biological minimum, so the amount of fat required for basic physiologic function, is around 4 to 6%, and below that you start to see hormonal disruption, immune function issues, and other serious health consequences.

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Above around 25%, cardio metabolic risk begins to increase meaningfully. For adult women, the healthy range does sit notably higher, generally around 21 to 33%. Women carry more body fat than men at any given BMI, and this is normal and appropriate. It's driven by sex hormones, particularly estrogen, and it serves important physiological functions, including reproductive health.

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The biological minimum for women is around 15 to 18 percent, and when women drop below this, as can happen in elite athletes, physique athletes, or with disordered eating, the consequences include hormonal disruption, bone loss, and loss of menstrual function. Above around 35 percent, risk increases meaningfully for women. Now, these are broad population ranges, but there are several factors that shift what's normal, quote unquote, for any individual.

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So the first one is probably age. Body fat naturally increases with age in both sexes. This is a relatively normal physiological process. Although I say that, I haven't actually seen data in uh sort of ancestral tribes or anything. So maybe this didn't happen back a million years ago. Anyway, but as I'm talking about it here and now, these shifts are driven by changes in metabolism, hormones, and body composition.

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We lose muscle mass as we age, which can shift the ratio toward fat even without any change in lifestyle. Older adults will have higher normal body fat values than younger adults. Women over 60, for example, may have values up of around 40 % that still fall within population norms for that age group. So what I would like to add here though, is that this is a population norm, but norm and health aren't the same thing.

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the ranges for older adults are, they're just descriptive. They reflect what we commonly see in the population, but they're not necessarily prescriptive targets to aim for. So it isn't suggesting that 40 % is associated with good health. And I will say that, you know, research on older adults and body fat is pretty complex. And there is something called the obesity paradox, where some studies find that slightly higher body fat in older adults is associated with

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better survival outcomes, possibly because fat mass provides metabolic reserve during illness or hospitalization, and also potentially it's protective if an adult might fall, for example. So very low body fat in older age carries risk. But even though body fat naturally increases with age, we really also want to tease out where that body fat is actually accumulating. And as said, you do not want the

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visceral fat accumulation that drives cardio metabolic risk to be the reason for this increase in body fat percentage, which is actually often the case. So even though the broad consensus might be that age is a natural process with which body fat percentage increases,

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And this is what we see across the board. I wouldn't necessarily say this is a healthy or desirable outcome. And the other thing to make note of here is of course, older adults, rising body fat percentage often does also reflect sarcopenia, which is a loss of muscle mass that Professor David Scott was chatting about last week. So the 40 % figure may partly be telling us that someone has lost significant muscle, which is independently dangerous for things like falls, frailty, or metabolic decline.

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it's not just that they're carrying more body fat. So whilst with aging, there is this increase in body fat. It's a normal thing that we see, but it's not necessarily a healthy thing that we see. Another area where we see individual differences is of course ethnicity. So Asian populations tend to reach kado metabolic risk at lower body fat percentages than white populations with the same BMI. Meaning that the typical cutoffs may underestimate risk in Asian populations. Non-Hispanic

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Black adults, Maori and Pacific populations, conversely, tend to have lower body fat at a given BMI compared to white or Asian populations. So country-specific studies from China, for example, have established obesity cutoffs around 28 to 33 % for men and 29 to 37 for women, which are lower than the Western figures that are typically cited. And then of course, there's that concept of normal weight obesity.

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which I think is really important for people to appreciate and get a better understanding of. And this is where someone has a BMI that falls in the normal range, but their actual body fat percentage is elevated. Studies have found that these individuals can still have significantly elevated cardiometabolic risk, elevated insulin resistance, and worse metabolic markers than their BMI would suggest. So BMI alone, while useful at a population level, can miss a meaningful group of people.

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who are carrying metabolically problematic levels of fat that aren't captured by standard screening. And then of course, you know, this is something that Brandon talks a lot about, the body fat percentage targets that circulate in fitness spaces. And I think this is where a lot of people get caught up because there is a disconnect between what's optimal from a health perspective and what gets promoted in performance or aesthetic contexts. So the American Council on Exercise, for example, classifies body fat ranges for men

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is essential at 2-5%, athletes at 6-13%, fitness at 14-17%, acceptable at 18-24%, and obesity at 25 % and above. For women, the categories run at essential body fat at 10-13%, athletes at 14-20%, fitness at 21-24%, acceptable at 25-30%.

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31 % body fat and obesity at 32 % and above. And you know, these are reasonable general guidelines. They do broadly overlap with other research, but it is worth noting that the athlete level of body fat, 6 to 13 % range for men or 14 to 20 % for women isn't where most people need to be for good health. And this is something Brandon pointed out in his podcast that I was listening to last year. And I will link that in the show notes.

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Those are ranges associated with competitive performance or aesthetic goals, and maintaining them often requires a level of dietary and training vigilance that isn't sustainable or necessary for most people. So where these numbers may, I guess, converge might be that from a metabolic health perspective, men aiming to stay around 17 to 20 % body fat and women

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below around 29 to 32 % are in a good position health-wise. So this may be a much more achievable and sustainable target for most people to feel fit, to have a pleasingly aesthetic look, and to be at lowest risk for these metabolic health outcomes. And I do want to just briefly touch on how we measure body fat, because a lot of people bring to me their data from their BIA machine and they're like, you know,

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This is telling me this X number, how accurate is this? And of course I've done a couple of podcasts on this very topic and I spoke to Grant Tinsley who is an expert in measuring body composition. Let me take you through the, I guess the levels of hierarchy if you like. um There's more than this, but this will work down from sort of where the gold standard might sit and what most people have access to. So there is...

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something called the Four Compartment Model, which is a DEXA. It's gold standard from the research perspective. It separates body fat into fat mass, water, mineral, and protein and requires multiple independent measures, including body volume, total body water via isotope dilution, and bone mineral content via DEXA. So it's extremely accurate, but it's only really used in research settings. Time consuming, expensive, and requires specialized equipment.

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And then we've got Dexer, which is something which you can get. It's not overly cheap, yet it's not like thousands of dollars, it's a few hundred dollars. ah And you can often get one through a sports medicine clinic or a research facility. And here in Auckland, there used to be places you could just sort of like use a pay, go and grab one. And I'm not actually sure that that still exists at the minute, but Dexer is a two compartment model. So it separates fat mass from fat free mass with

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bone pulled out separately, which is different from that four compartment model separately measuring fat, water, mineral, and protein. So DEXA estimates fat mass based on what's left over after accounting for bone and lean tissue. So it is worth noting that. It's also worth noting that different DEXA manufacturers give different algorithms, use different algorithms and give meaningfully different readings based on the same person.

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And there have been studies that have found discrepancies on several percentage points between machines. So it's good, it's worth knowing that. Some machines are better at distinguishing visceral fat from subcutaneous fat than others. And you do need some specific additional software with which to do it. Hydration status can still affect readings with DEXA. Overall, it is still better than bioelectrical impedance or BIA machine.

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What we do know, what I will say about DEXA is that it's most notably useful for assessing your bone mass. Now, what about bioelectrical impedance analysis in the BIA machines, which is what you encounter most commonly, whether it's the gym in-body machines, clinical tonnita devices, or those bathroom scales that tell you your body fat percentage. The principle is that a small electrical current is passed through the body.

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and resistance to that current is used to estimate body composition because fat tissue and lean tissue conduct electricity differently. BIA is non-invasive, fast and affordable, but the evidence on the accuracy is definitely worth discussing. So a 2026 systematic review published just this year compared multiple BIA machines against the four compartment criterion model across 12 studies. They found

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While the average bias between BIA and the Criterion Method was sometimes reasonably small, ranging from about minus 3.5 to plus 4.4 percentage points for body fat, the limits of agreement were very wide. We're talking 15 to 20 percentage points wide. So in practice, this means that for any individual person, your BIA reading could be several percentage points higher or lower than your true body fat percentage.

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So it's a meaningful margin if you're trying to track changes or make clinical decisions. Several factors affect BIA accuracy significantly. Your hydration status is probably the biggest one. Being even mildly dehydrated will inflate your reading. Recent exercise, food intake, time of day, menstrual cycle phase in women, and specific device and equation being used all introduce variability.

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Different BIA devices use different algorithms and researchers show and they don't always agree with each other. You can get different readings from two different devices on the same day. I guess the practical take home here is this, if you're using BIA to monitor your body composition over time, the most important thing is consistency. Use the same device at the same time of day under the same conditions. Ideally first thing in the morning, well hydrated before eating.

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look at trends over weeks and months, not day to day fluctuations, and be appropriately skeptical of any single reading as an absolute truth. Skin fold measurements, where calipers are used to print skin at specific sites and measure subcutaneous fat thickness, I think these can be reasonably accurate in the hands of a skilled practitioner using validated protocols. And such protocols come from, like the International Society for the Advancements of

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can that anthropometry or ISAC. So it's used to assess body composition and body size and practitioners get formally accredited at different levels, levels one through four. I think I got to level two on that, but I'm not particularly detailed, so it's never that good, if I'm honest. So these skin folds, which are taken at eight sites, if you do a full profile, can then be plugged into predicted equations to estimate body fat percentage or

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As I was taught, they can be used as summer skin folds, where many practitioners also prefer this because it avoids additional error introduced by the prediction equations themselves. Girth, such as waist, hip, or limb circumferences, and bone breads are also measured. So that's another super cheap and reasonably accessible way as long as you've got a practitioner who is accredited in something like Isaac and who's very skilled.

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And then of course waist circumference, often underrated as a tool. It's simple, it's free, and it's closely related with visceral fat. General thresholds from the research suggest elevated risk at waist circumference above 94 centimeters in men and 80 centimeters in women, with substantially elevated risk above 102 centimeters in men and 88 centimeters in women. Again, these aren't perfect, but as a quick practical health check, they're pretty useful.

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And don't forget that waist to height ratio either, with a cutoff of 0.5 when you're looking at risk from a cardio metabolic perspective. So let's bring it back to the original question. What even is a healthy level of body fat? For most adult men staying somewhere in the region of 10 to 20 % is associated with good cardio metabolic health. And at above 25%, your risk starts climbing.

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For adult women, somewhere in the 20 to 32 % range is associated with lower risk, above 35 % risk increases. So, I just want to leave you with this. The goal when we're thinking about healthy body fat levels isn't about aesthetic leanness. The research doesn't require you to be as lean in the way that fitness culture sometimes implies. A moderate, sustainable body fat percentage, one you can maintain through consistent health-promoting behaviours, is what matters.

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not having a six pack, eating a salad on Instagram, like almost every 40 something plus woman fitness influencer that I follow. Second, where your fat sits matters as much as how much you have. So if you carry fat predominantly in the hips and thighs rather than around your abdomen, your risk profile is actually better than someone with the same total body fat, but with more central distribution. Waist circumference is a pretty simple tool for assessing this. And

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Body fat is just one piece of the picture. Cardio respiratory fitness, muscle mass, strength, diet quality, sleep and stress management, all of these contribute independently to health outcomes. Improving body composition definitely is important, but it doesn't happen in isolation from these other factors. And finally, if you're genuinely curious about where you set in terms of your body fat percentage levels and your overall health risk,

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The most useful thing you can do is speak with a healthcare provider who actually looks at the full picture. So not just body fat percentage, but also glucose, blood pressure, your lipid profile, your waist circumference, and your individual health history and your habits, lifestyles and behaviours. So a single number from your bathroom scale is a starting point, but not a complete assessment. All right, team, that's Mini Micropeda for this week.

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And as always shout out to my mentors and mates like Brandon who really does encourage me to just look a little bit deeper into topics which then gives me great content for Mini Mikkipedia. Alright guys, you have the best week. I'm over on Instagram threads and X @mikkiwilliden Facebook @mikkiwillidennutrition or head to my website, mikkiwilliden.com. Book a one-on-one call with me.