A new study suggests that being overweight is not necessarily an enemy of health. The Danish research team found that people who are slightly heavier than the normal weight range have a lower risk of premature death compared to those who are underweight. Conversely, being excessively thin was found to significantly increase the risk of premature death, revealing that the relationship between weight and health is not as simple as commonly believed.

A joint research team from the Steno Diabetes Center Aarhus and Aarhus University Hospital in Denmark tracked the health data of 85,761 adult men and women over an extended period to analyze the correlation between body mass index (BMI) and mortality. BMI is calculated by dividing weight (kg) by height squared (m²); a BMI below 18.5 is considered underweight, 18.5-25 is normal, 25-30 is overweight, and 30 or higher is classified as obese.

Overweight individuals have a lower risk of premature death than thin people

Excessively thin body types significantly increase the risk of premature death

Underweight causes malnutrition and weakened immunity
It is possible to be overweight but healthy

When setting obesity treatment goals,
a personalized approach considering fat distribution and diseases,
not just simple weight numbers, is necessary Photo by Getty Images Bank

According to the analysis, individuals in the overweight category did not have a higher likelihood of premature death than those at the upper boundary of the normal weight range. In fact, people with a BMI in the middle or lower boundary of the normal range (18.5-22.5), as well as those classified as underweight, had a higher risk of premature death. The underweight group had a 2.73 times higher risk of premature death compared to those at the upper end of the normal range. Of course, individuals with severe obesity (BMI of 40 or higher) also had more than twice (2.1 times) the risk of premature death compared to those in the normal weight range.

On the other hand, being overweight or having early-stage obesity (BMI 30-35) did not show a significant difference compared to the upper end of the normal range. However, severe obesity (BMI 40 or higher) was associated with a 2.1 times higher risk of death, and a BMI of 35-40 increased the risk by 23%. This aligns with previous research indicating that obesity negatively impacts health once it exceeds a certain level. The research team explained that mortality rates did not increase up to a BMI of 35, and the increase in risk for a BMI of 35-40 was relatively small.

Sigrid Bjerge Gribsholt, a professor at Aarhus University Hospital who led the study, explained, "Both underweight and obesity are global public health issues. Obesity can lead to metabolic disturbances, weakened immunity, type 2 diabetes, cardiovascular disease, and cancer, while underweight can cause malnutrition and weakened immunity." She added, "This study demonstrates that it is indeed possible to be 'fat but fit.'" She emphasized, "When setting obesity treatment goals, a personalized approach that considers fat distribution and comorbidities, rather than simply focusing on weight numbers, is necessary."