Trends in the double burden of malnutrition among Indonesian adults, 2007 to 2023.

Indonesia, like many low- and middle-income countries (LMICs), faces a double burden of malnutrition, with undernutrition and obesity coexisting within its population. Despite previous studies analyzing malnutrition trends between 1993 and 2007, a gap remains in understanding how these trends have evolved, particularly across different demographic and socioeconomic groups. This study aims to examine the national trends of undernutrition (BMI < 18.5 kg/m²) and obesity (BMI ≥ 25 kg/m², Asian cutoff) using a repeated cross-sectional analysis conducted using Indonesia Health Surveys 2007, 2013, 2018, and 2023, with a nationally representative sample of 2.4 million Indonesian adults aged ≥ 20 years. Anthropometric measurements were standardized, and sensitivity analyses accounted for missing data. Weighted logistic regression models were used to estimate adjusted odds ratios (AORs) for undernutrition and obesity, adjusting for key demographic and socioeconomic variables. Between 2007 and 2023, the prevalence of underweight declined from 12.3 to 7.5%, while obesity nearly doubled from 19.7 to 38.3% (Asian cutoff). The shift was more pronounced among urban women, whose obesity prevalence rose from 30.1 to 49.9%, and in the highest income group, where obesity surged from 25.6 to 48.3%. Central adiposity (waist circumference ≥ 80 cm in women, ≥ 90 cm in men) has also increased significantly since 2007, reaching 42.0% by 2023. Age-specific trends revealed a U-shaped underweight prevalence (highest among young adults and elderly) and an inverted U pattern for obesity (peaking in midlife). Multivariable analysis confirmed strong socioeconomic gradients, with the wealthiest quintile at higher risk of obesity (AOR = 2.13, 95%CI = 2.09-2.17) and lower risk of being underweight (AOR = 0.47, 95%CI = 0.46-0.49) than the poorest quintile. Compared to women, men were less likely to be obese (AOR = 0.38, 0.38-0.39) and at higher risk of underweight (AOR = 1.33, 95%CI = 1.30-1.36). Indonesia's nutrition transition is accelerating, with obesity rising much faster than undernutrition is declining. The country is in a stage where higher socioeconomic groups remain the most affected, but lower-income populations are increasingly at risk. Without timely intervention, obesity may soon become disproportionately concentrated among poorer populations, as seen in other transitioning economies.