Association Between Sugar Intake, Body Mass Index, Income, and Life Expectancy: A Global Analysis

Background: Life expectancy is shaped by a combination of lifestyle and socioeconomic factors. While sugar consumption, body mass index (BMI), and income have been individually linked to health outcomes, their combined effects on longevity—particularly across countries with differing development levels—are less well understood. Objective: This study investigates how sugar intake, BMI, and per capita income interact to influence life expectancy across 187 countries. Methods: We conducted a cross-sectional analysis using national-level data from FAOSTAT, the World Bank, and the World Health Organization for the years 2022–2023. Pearson correlation was used to assess bivariate relationships, and multiple linear regression was employed to estimate the collective impact of BMI, sugar consumption (kg per capita/year), and income (USD) on life expectancy (years). The model was adjusted for confounding variables such as healthcare expenditure, education, and smoking prevalence. Results: Sugar intake was moderately associated with BMI (r = 0.52) and life expectancy (r = 0.50), with p value <0.05 for both with stronger relationships observed in countries with per capita income below USD 10,000. BMI also showed a moderate positive correlation with life expectancy (r = 0.49), but this association weakened—and slightly reversed—for countries with BMI greater than 27 kg/m². The regression model explained 33.9% of the variance in life expectancy (adjusted R² = 0.325), increasing to 61.6% after accounting for structural confounders. Conclusion: BMI and sugar intake are important predictors of life expectancy, with their impact shaped by income level and healthcare infrastructure. The decline in longevity above a BMI threshold of 27 kg/m² highlights a critical point for public health intervention. Integrated strategies targeting obesity, sugar intake, and structural inequities are essential for improving global health outcomes.