Objectives: To characterize the health behaviors and outcomes of first-year international students (FYIS) studying in the U.S. Participants and methods: Three different cohorts of FYIS from a large midwestern university in the U.S. completed three laboratory visits between August and March. The study began in 2017 and ended in March 2020. Anthropometrics, acculturative stress, eating behaviors, sleep, physical activity, and eating habits were assessed. Results: Fifty-four students completed the study. Females had a significant increase in percent body fat (p = 0.036) and a decrease in sleep quality (p = 0.006) at the final visit vs. baseline, and uncontrolled (p = 0.006) and emotional (p < 0.001) eating behaviors were higher. FYIS who gained more than the median 1.2 kg over the study period experienced higher acculturative stress (p = 0.004) and a decline in sleep quality (p = 0.003). Conclusion: Reducing acculturative stress and improving sleep quality should be explored as interventions to protect against undesirable changes in adiposity among FYIS.