This study examines the impact of overweight and obesity on life expectancy and premature death in adults, focusing on participants from the Framingham Heart Study who were 30 to 49 years old at baseline. The analysis, conducted from 1948 to 1990, found that obesity (body mass index [BMI] ≥ 30 kg/m²) at age 40 was associated with a significant decrease in life expectancy, with obese individuals losing 6 to 7 years of life compared to those with normal BMI. Overweight (BMI 25 to 29.9 kg/m²) was also linked to a 3-year reduction in life expectancy. The study highlights that obesity and overweight are strong predictors of early mortality, similar to the effects of smoking. The findings emphasize the importance of obesity prevention and treatment as high priorities in public health, given the increasing prevalence of these conditions.This study examines the impact of overweight and obesity on life expectancy and premature death in adults, focusing on participants from the Framingham Heart Study who were 30 to 49 years old at baseline. The analysis, conducted from 1948 to 1990, found that obesity (body mass index [BMI] ≥ 30 kg/m²) at age 40 was associated with a significant decrease in life expectancy, with obese individuals losing 6 to 7 years of life compared to those with normal BMI. Overweight (BMI 25 to 29.9 kg/m²) was also linked to a 3-year reduction in life expectancy. The study highlights that obesity and overweight are strong predictors of early mortality, similar to the effects of smoking. The findings emphasize the importance of obesity prevention and treatment as high priorities in public health, given the increasing prevalence of these conditions.