Reputable sources for nutritional information include established organizations like the Academy of Nutrition and Dietetics, the World Health Organization (WHO), and government health departments like the U.S. Department of Agriculture (USDA). Academic journals and peer-reviewed publications also provide credible research on nutrition. Websites associated with registered dietitians or certified nutritionists can be reliable, as they base their information on scientific evidence. It's essential to cross-reference information and consult professionals for personalized advice.