Food Literacy
The first article about fat here meant the fat on your plate: what it builds, why your brain is roughly 60% fat by dry weight, and how three decades of low-fat messaging got the story wrong. That article was about the fat you eat.
This one is about the fat you carry. The part that surprises most people is that the amount matters less than the address.
Two people can weigh the same and wear the same size while storing that weight in completely different places. One stores it under the skin, where you can pinch it. The other stores it deep in the abdomen, packed around the liver and intestines, where there is nothing to pinch. The second person often looks like the healthier of the two.
Correction notice, 28 August 2026. Three things in this article were checked against their primary sources and did not hold. They are marked where they appear rather than quietly deleted:
- the waist measurement was taken level with the navel. The published method for measuring your own waist puts the tape midway between your lowest rib and the top of your hip, which sits higher on most people. If you recorded a number using the old instruction, take it again
- vitamin D was listed as a marker that sees inside. Fat tissue does lower it, which is why it still appears earlier in this article, but a vitamin D result does not tell you where your fat is
- the closing position recommended fiber, water and regular bowel movements as the route your body clears stored pollutants by. No human evidence for that turned up, and it sat one paragraph below a paragraph promising not to imply a mechanism just because it sounds convincing
What the article is actually about, that the fat you cannot pinch is the fat that matters and a tape measure finds it before a scale does, is unchanged.
The principle. Body fat is not inert storage. It is an active endocrine organ that releases hormones and inflammatory signals into your bloodstream, and the portion packed around your organs behaves very differently from the portion sitting under your skin.
Two Kinds of Fat, One Word
One word, “fat,” covers two tissues that do different jobs.
| Subcutaneous fat | Visceral fat | |
|---|---|---|
| Where it sits | Under the skin | Behind the abdominal wall, around the organs |
| Can you pinch it | Yes | No |
| Shows on the scale | Yes | Yes, but indistinguishably |
| Metabolically active | Somewhat | Considerably more |
| Drains into | General circulation | The portal vein, straight to the liver |
That last row does most of the work. Visceral fat empties into the portal vein, delivering its output straight to your liver before the rest of the body sees any of it. Subcutaneous fat has no such shortcut.
So a person can carry a risky amount of visceral fat at a weight nobody would comment on. Thomas and colleagues (Obesity, 2012) used MRI to map where fat actually sits and named the pattern TOFI, thin on the outside, fat on the inside: a normal BMI hiding a large internal fat depot. The mirror and the pinch test measure the fat that matters least.
What Visceral Fat Does While You Are Not Thinking About It
It files away your vitamin D. Vitamin D is fat soluble, so it dissolves into fat tissue instead of circulating where your body can use it. Wortsman and colleagues (American Journal of Clinical Nutrition, 2000) gave participants whole-body UV light and found the rise in blood vitamin D was roughly 57% lower in the participants with obesity than in the others, from the same dose. Same sunlight, less delivered. If you get sun, supplement, and still cannot move your numbers, body composition is worth looking at.
It makes its own estrogen. Fat tissue expresses aromatase, the enzyme that converts androgens such as testosterone into estrogens, so more fat tissue generally means more of that conversion. Wang and colleagues (Journal of Steroid Biochemistry and Molecular Biology, 2015) describe aromatase overexpression in dysfunctional fat tissue as one link between obesity and postmenopausal breast cancer risk. In men, the same enzyme turns testosterone into estradiol, and low testosterone and central fat feed each other: Kelly and Jones (Obesity Reviews, 2015) call this two-way link the hypogonadal-obesity cycle, and note that weight loss can raise testosterone. Worth knowing: one drug class used against certain breast cancers is an aromatase inhibitor, aimed at that enzyme.
It interrupts the message that you are full. Leptin is how fat tissue tells your brain there is enough stored energy on board. More fat means more leptin, but obesity also sets off cellular changes that blunt leptin signaling, a pattern called leptin resistance (Myers and colleagues, Trends in Endocrinology and Metabolism, 2010). Whether that causes weight gain or follows from it is debated. Either way, more fat does not produce a stronger stop signal.
Your Fat Cells Run Short of Oxygen. Then Your Immune System Shows Up.
Fat cells can expand faster than the blood vessels feeding them. Trayhurn (Physiological Reviews, 2013) laid out the consequence: enlarged fat tissue becomes relatively hypoxic. Stressed and dying fat cells attract immune cells, which release inflammatory molecules including TNF-alpha, first tied to fat tissue and insulin resistance by Hotamisligil and colleagues (Science, 1993). Your liver answers those signals by producing C-reactive protein.
That matters practically, because CRP appears on ordinary blood panels. A raised hs-CRP tells you inflammation is happening somewhere, not where. Visceral fat is a common answer and one of the few you can directly change. It shows up in outcomes too: Pischon and colleagues (New England Journal of Medicine, 2008) followed roughly 360,000 people across Europe in an observational cohort and found waist circumference associated with mortality risk independent of BMI. Same BMI, different waists, different risk.
The Part Almost Nobody Mentions
Fat is also where your body files fat-soluble compounds it cannot immediately clear. Many industrial pollutants are lipophilic: they dissolve into fat rather than water. Persistent organic pollutants such as PCBs and dioxins accumulate there over years. In the short term that is arguably protective, since a compound parked in fat is not circulating past every cell you own.
The complication arrives when the fat comes off. Chevrier and colleagues (International Journal of Obesity, 2000) measured pollutant concentrations in people losing weight and found plasma levels rose as fat mass fell. Cheikh Rouhou and colleagues (Diabetes and Metabolism, 2016) later asked whether that release explains some of the adverse effects seen after weight loss. The question is open. The release is well documented.
Two compounds in this category already have entries on the Dirty List: BPA, the can-lining chemical, and PFAS, the forever chemicals.
Where Diet Discipline Stands
This is where somebody usually tries to sell you a detox protocol, so the evidence and the opinion are kept apart here.
The evidence: fat tissue stores these compounds, and losing fat releases them into circulation. Measured in humans, repeatedly. Not established: that any cleanse, supplement stack or detox program improves how your body handles that release. No good human evidence for it has turned up, and nothing here implies otherwise just because the mechanism sounds convincing.
The position here: the answer to a real mechanism is not a product, it is a pace and a direction. Take fat off steadily rather than as fast as possible, and reduce what is arriving now, which is the half of this that is fully under your control.
What this article will not do is tell you how to speed up the clearing. The literature was searched. The only approach with human data behind it is olestra, a fat your gut cannot absorb, which carries these compounds out with it. Moser and McLachlan (Chemosphere, 1999) measured excretion rising by a factor of 1.5 to 11, in three volunteers. Jandacek and colleagues (Journal of Nutritional Biochemistry, 2014) ran a year long randomized trial in 23 people and saw faster elimination on olestra, while the comparison between the two groups fell short of significance. Fiber and chlorophyll have shown the effect in rats. That is the entire file: two small studies of a manufactured food additive, which is not a habit and not something recommended here. Anyone selling you a protocol has less than this.
What changed: this section used to close by telling you to support “the routes your body already uses, which run on fiber, water and regular bowel movements.” That was the same detox mechanism refused a paragraph earlier, wearing free clothes. Fiber and water are still in the protocol below, for the things they actually do.
Myth vs Reality
Myth: If I cannot pinch it, I do not have it.
Reality: Visceral fat sits behind the abdominal wall, out of reach of the pinch test.
Myth: A normal BMI means normal metabolic health.
Reality: BMI describes weight against height and says nothing about where that weight sits, which is why TOFI exists as a described pattern.
The Protocol
1. Measure your waist. It takes 60 seconds. Find the bottom of your ribs and the top of your hips, and run the tape around midway between the two, which lands just above the navel on most people. Breathe out normally, do not suck in. Divide the number by your height in the same units. That is the method the National Institute for Health and Care Excellence, the body that writes clinical guidance for the UK health service, publishes for people measuring themselves, and it reads the result in three bands: 0.4 to 0.49 no increased risk, 0.5 to 0.59 increased, 0.6 or more higher still. It needs no appointment.
What changed: this step used to say to measure level with the navel, which sits below the correct site on most people. If you have a number written down from before, it is not comparable to one taken this way. Start the record again.
2. Ask for the markers that see inside. At your next blood draw: fasting glucose or HbA1c, triglycerides and HDL, hs-CRP. Those three say more about visceral fat than the scale does. Vitamin D is worth having on the same draw for the reason described above, that fat tissue holds on to it, but it is not one of these markers: season, sun exposure, skin tone and whether you supplement all move a vitamin D result, so a low one does not tell you where your fat is.
3. Choose steady over rapid. Slower fat loss is not weaker discipline. Given what the fat is holding, it is the more considered choice.
4. Reduce what comes in. Cook and store in glass or stainless rather than plastic, skip food that arrives in grease-resistant wrappers, and read the packaging as carefully as the label.
5. Give fiber and water their real job. Most people run a 10 to 20 gram daily fiber gap, and hydration is the other half. Neither one clears stored pollutants, and this step used to imply that they did. They earn their place here on their own merits, which are large enough without borrowing somebody else’s.
What to Watch Over 4 to 12 Weeks
Waist measurement, taken the same way on the same day of the week. It often moves before the scale does, and it tracks the fat you actually care about. Also notice whether meals hold you longer than they used to.
For context: 72.4% of American adults aged 20 and over are overweight or have obesity, per CDC National Center for Health Statistics data for August 2021 to August 2023. If that describes you, you are the majority, not an outlier.
Your action step, today. Find a tape measure. Measure your waist midway between your lowest rib and the top of your hip, divide by your height, and write both numbers down with today’s date.
That one ratio tells you more about the fat that matters than your scale has told you all year, and you can repeat it at home, for free, for the rest of your life.
Latest health news
