Aim: To investigate the association among genetics, lifestyle and environmental factors in obese and non-obese university students in Malaysia. Subjects and methods: A cross-sectional study was conducted on students who were studying at universities in Selangor and Kuala Lumpur, Malaysia. Face-to-face interviews were conducted using a pre-tested, self-administered questionnaire, consisting of three major parts: demographics, factors influencing body weight and actions to alter or maintain the present body weight. Results: Most of the parents and siblings of young obese participants were also obese compared with non-obese participants (p < 0.001). Family and friends had an influence on the eating habits of both obese and non-obese participants. About 40% of obese participants had a smoking habit. Non-obese participants did not eat much differently, whilst obese participants increased their food intake when they had fewer sleeping hours (p = 0.002). Only 29% of obese participants preferred fruit or vegetables, while 71% preferred salty, baked, fatty and sugary food. More than 50% of non-obese participants always had breakfast. None of the obese participants exercised daily. Stress and poor time management were the major factors preventing obese participants from losing body weight, while encouragement from family members, peers and social influencers were the major motivators for non-obese participants to maintain their body weight. Conclusion: Genetics, family and friends, sleep, eating habits, smoking, physical activity and stress have influences on both obese and non-obese cohorts. Obese populations should adopt good discipline, have adequate sleep, observe a healthy diet and maintain an active lifestyle to reduce body weight. [ABSTRACT FROM AUTHOR]