Introduction: Nutritional status is an indicator of health status that can be determined using the Body Mass Index (BMI) (kg/m2). This study aimed to determine factors affecting the nutritional status of adults, pre-elderly, and elderly. Methods: This cross-sectional study used secondary data from 13,655 respondents aged 36– 66 years that were a part of the 2014 Indonesian Family Life Survey (IFLS). Food consumption patterns, physical activity, and socio-demographic data were used to assess nutritional status (BMI). Results: Consumption patterns of carbohydrates, protein, fat, vegetables, and fruits were significantly associated with mean BMI as an increase in consumption score led to an increase in mean BMI. Conversely, greater physical activity resulted in a decrease in mean BMI. Mean BMI among females was higher than that of males, irrespective of factors such as marital status, unemployment, presence of health insurance, or smoking. Sumatranese people had the highest mean BMI among the population, along with senior high school graduates and high-income earners. Both higher income and education levels led to higher mean BMI. Conclusion: Many factors were shown to affect nutritional status. The results imply that solving nutritional problems in order to improve quality of life will involve many factors, including socioeconomic variables, which are important for designing and evaluating health programmes.