Extra Pounds Linked To Lower Death Risk In Seniors — With One Exception

Study Warns That Being Underweight At 65 Tied To Sharply Higher Risk Of Dying

For decades, doctors have told older Americans to lose weight. But a major new study tracking nearly 7,000 seniors over 14 years is turning that advice on its head, at least in part. Where fat is stored on an aging body may matter far more than how much someone weighs overall.

Published in the Journal of the American Geriatrics Society, the study found that older adults classified as overweight actually had a lower risk of dying from any cause than their peers at so-called “normal” weight, and in men, mild to moderate obesity was linked to lower risk as well. At the same time, carrying extra fat specifically around the belly was linked to a higher death risk, regardless of overall weight. It’s a finding that unsettles one of the most stubborn assumptions in American medicine.

For millions of older adults who have spent years being nudged by their doctors toward a lower number on the scale, this research raises an uncomfortable question: Has the medical community been focused on only part of the picture all along?

Why Body Mass Index Alone May Be Misleading Seniors

At the center of this story is a familiar number: body mass index, or BMI, a simple ratio of weight to height that doctors have used for generations to categorize patients as underweight, normal, overweight, or obese. It’s fast, cheap, and easy to calculate. It also has a well-documented blind spot: it can’t tell the difference between fat and muscle, and it offers no information about where fat actually sits on the body.

Researchers leaned into that blind spot. Using data from the National Health and Aging Trends Study, a nationally recognized long-term research project, they tracked 6,905 adults aged 65 and older from 2011 to 2024. Rather than relying on a single weight measurement taken at the start of the study, they tracked how participants’ BMI and waist size changed over time. That approach matters because a person’s body composition doesn’t stay frozen in place, especially over 14 years of aging.

Waist size, a simple indicator of fat carried around the middle, was analyzed alongside BMI to understand how the two measurements interact. A larger waist is widely considered a reliable sign of fat stored around the midsection and internal organs, which has long been associated with heart disease and metabolic problems.

Belly Fat and Body Weight, by the Numbers

Among male participants, those classified as overweight had a 46% lower risk of dying during the study period compared to men at normal weight. Men in the lower two tiers of obesity had a 51% lower mortality risk than normal-weight men. Overweight women showed a similar, though smaller, reduction in risk; for mild to moderate obesity, the lower mortality was clear only in men, not women.

When looking at waist size separately, men with a high waist measurement faced a 24% greater risk of death compared to those with a lower measurement. A parallel pattern was observed in women.

When researchers combined both measurements, the results became even more telling. Overweight older adults had lower mortality risk regardless of whether their waist size was high or not. Men with obesity and a large waist still had lower mortality risk than normal-weight men. But being underweight, no matter the waist size, was associated with a much higher death risk in both men and women.

Perhaps most revealing: older adults at a “normal” BMI who carried excess belly fat faced elevated mortality risk, meaning they looked fine on paper but were in greater danger than many of their heavier peers.

These results were adjusted to account for factors that could otherwise skew the findings, including age, race, education, income, smoking status, and whether participants were homebound.

Making Sense of the “Obesity Paradox”

Researchers have observed before that being somewhat overweight appears protective in older populations. Scientists have a name for it: the “obesity paradox,” a pattern where the usual risks tied to higher body weight seem to flip in elderly people. One possibility is that preserved muscle or greater metabolic reserve partly explains the association. Another is that people who reach old age at a higher weight may simply be a hardier group to begin with. The authors caution, though, that reverse causation, undiagnosed illness that lowers weight before death, and survivorship bias could all make a higher BMI look more protective than it truly is.

Where the body stores fat shifts that picture considerably. Carrying extra weight overall in older age was linked to lower mortality, not higher. Carrying it specifically around the middle showed the opposite.

As the authors wrote, the results “highlight the adverse association of central adiposity and the limitations of BMI-only classification for mortality risk stratification in older adults” (Xu et al., Abstract, Conclusions). In other words, an older person’s waist measurement may flag mortality risk that the number on the scale misses.

Rethinking How Doctors Weigh Belly Fat Risk

Standard clinical practice still leans heavily on BMI. Patients get flagged as overweight or obese based on that number, and weight loss is frequently recommended. In older populations, that approach may be both imprecise and actively misleading.

An older adult at “normal” BMI with a large waist might be dismissed as healthy based on weight alone, when in reality they face elevated mortality risk. Conversely, an older adult who is technically overweight by BMI standards may carry a different risk profile than the number alone would suggest.

Underweight older adults emerged as a particularly high-risk group in this study. Muscle loss, poor nutrition, and underlying illness can all drive weight down in older people, and the mortality risk tied to low body weight in this population is serious.

For the roughly 57 million Americans aged 65 and older, this research makes a case for doctors to look beyond BMI alone and also weigh where body fat is carried.

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Disclaimer: This article describes an observational study. Research of this kind can reveal that two things tend to occur together, such as belly fat and a higher risk of death, but it cannot prove that one directly causes the other. Factors the researchers could not fully account for, including underlying illness that lowers body weight before death, may influence the results. Findings should not be taken as personal medical advice; decisions about weight, diet, or health should be made with a qualified clinician.

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