Purpose: Guided by the cognitive load theory, the purpose of this study was to determine the impacts of cognitive load and school socioeconomic status-related environmental factors on ninth-graders' energy-balanced living knowledge gain. Methods: A stratified random sample of high-school students (N = 150) participated in this study. Data were collected on students' knowledge gain, cognitive load, free and reduced-price meal rates, and student-to-teacher ratio. Results: The path analysis results revealed that the reasoning learning tasks had direct significant effects on students' knowledge gain ([beta][subscript i-Diet and i-Exercise] = 0.34, p < 0.01). The free and reduced-price meal rates and student-to-teacher ratio did not have significant effects on students' knowledge gain (p > 0.05). Discussion: These findings advance our understanding of the role cognitive learning tasks play in enhancing student learning in the subjects of energy-balanced knowledge and healthy lifestyle