For decades, the bathroom scale and the body mass index (BMI) chart have been the default tools for judging health risk. Step on, read a number, and receive a verdict. But a body of research has steadily undermined the idea that a single weight figure tells the whole story. A study by Van Pelt and colleagues, published in the American Journal of Physiology – Endocrinology and Metabolism in 2002, offers a particularly clear illustration of why where the body stores fat may matter more than how much it stores overall — and why a thoughtful, well-planned diet remains one of the most important levers we have.
What the researchers found
The team measured total and regional body composition in 166 healthy postmenopausal women, averaging 66 years of age, using dual-energy X-ray absorptiometry (DEXA) — a scanning technology best known for measuring bone density but capable of breaking body fat down by region (trunk, arms, legs). They then compared these fat measurements against markers of metabolic and cardiovascular risk: insulin levels during a glucose tolerance test, an index of insulin resistance, triglycerides, and HDL ("good") cholesterol.
The standout result was that trunk fat — fat carried around the abdomen and midsection — was the single strongest predictor of poor metabolic health. Women with more trunk fat tended to show higher insulin resistance, higher triglycerides, and lower HDL cholesterol. Crucially, this relationship held up even after accounting for fat stored elsewhere in the body.
The more surprising finding concerned leg fat. Once trunk fat was statistically controlled for, greater leg fat was associated with a more favorable metabolic profile — lower insulin resistance, lower triglycerides, and a tendency toward higher HDL. To make the point vivid, the researchers looked at women who carried similar amounts of trunk fat but differed in leg fat. Those in the high-leg-fat group were less insulin resistant and had markedly lower triglycerides (roughly 98 mg/dL versus 192 mg/dL in the low-leg-fat group) despite having a higher overall body-fat percentage. Arm fat, by contrast, showed no independent relationship once trunk fat was taken into account.
In short: fat around the middle appears to carry metabolic risk, fat in the lower body appears to be comparatively benign or even protective, and total fatness alone is a blunt instrument. As the authors put it, the usefulness of BMI for assessing disease risk in this population is questionable.
Why location changes everything
The reason fat distribution matters comes down to biology that differs from one depot to another. Fat cells in the abdominal, and especially the visceral, region are more metabolically active — they release fatty acids more readily and are more resistant to insulin's signal to hold onto stored fat. Because abdominal fat sits close to the portal circulation that feeds the liver, the free fatty acids it releases can flood the liver directly, promoting triglyceride production and blunting the liver's ability to clear insulin. Lower-body, gluteal-femoral fat behaves differently: it tends to act as a more stable, long-term storage depot that keeps fatty acids out of circulation.
This heterogeneity is why two women of identical weight — or identical BMI — can sit at very different levels of cardiovascular and diabetes risk. The number on the scale cannot see the difference; the metabolism can.
Where nutrition enters the picture
Here an important caveat is worth stating plainly: the Van Pelt study was observational. It measured associations at a single point in time and did not test any diet or lifestyle intervention. It cannot, on its own, prove that changing what you eat will change where fat is stored or lower disease risk. What it does do is identify what to worry about — central adiposity and its metabolic fingerprint of insulin resistance and dyslipidemia — and those are precisely the outcomes that nutrition is known to influence.
That distinction is where a well-planned diet earns its importance. The markers this study flags as dangerous are among the most diet-responsive measures in all of medicine:
Insulin resistance and blood sugar. Insulin resistance is strongly shaped by the quantity and quality of carbohydrates, overall energy balance, fiber intake, and body fatness. Diets emphasizing whole grains, legumes, vegetables, and unprocessed foods — and moderating refined carbohydrates and added sugars — are repeatedly linked to improved insulin sensitivity. Since the study identifies insulin resistance as a central risk pathway, the food choices that improve it matter directly.
Triglycerides. Of all the blood lipids, triglycerides may be the most responsive to diet. Excess refined carbohydrate, added sugar, and alcohol reliably push them up; reducing these, along with weight loss and omega-3-rich foods, brings them down. The study found that women with a healthier fat distribution had dramatically lower triglycerides — a target a well-designed diet can move.
HDL cholesterol. Dietary patterns rich in healthy fats and low in refined carbohydrate, combined with physical activity, tend to support higher HDL. The study links this protective cholesterol to lower-body fat and a favorable overall profile.
Central fat itself. While genetics and hormones (menopause prominently among them) strongly influence where fat is deposited, total central fat is not fixed. Sustained changes in eating patterns and energy balance can reduce visceral and abdominal fat, and abdominal fat is often among the first to respond to a modest, consistent caloric deficit.
The case for planning, not just restricting
The word "diet" too often conjures short-term restriction. What this research argues for is closer to the opposite: a planned pattern of eating designed to influence specific metabolic outcomes over time. The study's own findings suggest why a scattershot approach falls short. Regional fat distribution explained only around 38 percent of the variability in insulin resistance, meaning the majority of the difference between individuals came from other factors — genetic predisposition, activity, and, plausibly, long-term dietary habits. Body composition is one piece of a larger, modifiable picture.
A well-planned diet works on several of those pieces at once. It manages energy balance to limit central fat accumulation. It shapes carbohydrate quality to protect insulin sensitivity. It moderates the sugar, refined starch, and alcohol that drive triglycerides. And it supplies the fiber, healthy fats, and micronutrients that a body — especially an aging one navigating the metabolic shifts of menopause — needs to function well. For postmenopausal women in particular, when the tendency to store fat centrally increases, being deliberate about food becomes less optional and more foundational.
The takeaway
The Van Pelt study is a reminder that health risk is written in the details of body composition, not just in a single weight or BMI figure. Trunk fat signals danger; lower-body fat does not carry the same burden; and the metabolic consequences show up in insulin, triglycerides, and cholesterol long before disease does.
We cannot fully choose where our bodies store fat — genetics and hormones cast a long shadow. But the downstream risks this research highlights are, to a meaningful degree, ones that nutrition can bend. A thoughtful, sustained, well-planned diet does not just chase a number on the scale. It works directly on the very markers that determine whether extra weight quietly becomes disease — which is exactly why planning what we eat is one of the most powerful health decisions within our reach.
This article is based on the findings of Van Pelt RE, Evans EM, Schechtman KB, Ehsani AA, Kohrt WM. "Contributions of total and regional fat mass to risk for cardiovascular disease in older women." Am J Physiol Endocrinol Metab 282: E1023–E1028, 2002. The original study was observational and did not test dietary interventions; the discussion of nutrition reflects broader, well-established evidence about how diet influences the metabolic markers the study identified. It is general information, not personalized medical or dietary advice.