Researchers from Aarhus University Hospital in Denmark have discovered that underweight individuals face roughly a threefold higher risk of dying compared to those who are overweight or even moderately obese — defying long-held beliefs about body weight and health.

A large-scale Danish study found that being slightly overweight — or even mildly obese — may not shorten life expectancy, while those who are underweight or at the lower end of the “normal” weight range face greater risks.

The study, presented at the annual meeting of the European Association for the Study of Diabetes (EASD) in Vienna, Austria, suggested that being “fat but fit” could be less deadly than being underweight.

Researchers tracked nearly 86,000 people, mostly women in their mid-60s, over five years, comparing their body mass index (BMI) to mortality rates.

Typically, a BMI between 18.5 and less than 25 is considered “normal”, 25 to less than 30 is “overweight”, and 30 or above is classified as obese.

However, the findings suggest that people with BMIs typically classed as “overweight” appear to have outcomes just as good as — or even better than — those with lower BMIs.

Researchers observed a U-shaped curve when plotting BMI against mortality, indicating that individuals with the lowest and highest BMIs were at the greatest risk of death.

People with a BMI below 18.5 were nearly three times more likely to die prematurely than those with a BMI between 22.5 and 24.9.

Those at the lower end of the “healthy” range also faced higher risks: individuals with BMIs between 18.5 and 19.9 had double the likelihood of death, while those with BMIs between 20 and 22.4 were at a 27% higher risk of early death compared with the reference group.

Carrying extra weight did not always translate to greater risk, as individuals with BMIs between 25 and 35 (typically categorized as “overweight” or “obese”) showed no significant increase in mortality compared with the reference group.

Only those with a BMI of 40 or more experienced a substantially higher risk of death, more than doubling (2.1 times) compared with the reference group.

These findings add to the growing body of evidence challenging the common societal belief that thinness equates to health. In fact, research shows that being underweight poses significant health risks, particularly in older age.

According to the researchers, factors such as body fat distribution and underlying health conditions play a major role in determining overall health outcomes.

The lead researcher suggested a phenomenon known as “reverse causation” — where some people lose weight because they are already ill, making it appear that being thin causes poor health, when in reality, the illness is responsible for both weight loss and increased risk.

While BMI is not a perfect measure of health, this study reinforces the growing view that we must rethink what a “healthy body” truly looks like. Health is not merely about thinness; it’s about balance, body composition, and overall well-being. (Nigerian Tribune)