This study aims to evaluate the outcome of a 12-week behavioral lifestyle modification program focusing on
the blood oxidative stress levels/activities in obese subjects and aims to examine the association between the changes in
blood oxidative stress levels/activities and modifications in serum lipid profile concentrations. An interventional study
was conducted involving thirty-four obese adults, all of whom were recruited from the Obesity Clinic, Hospital Universiti
Sains Malaysia. The subjects participated in the 12-week behavioral lifestyle modification program consisting of diet and
exercise interventions. Blood was obtained from the subjects at baseline (week 0) and after 12 weeks (week 13) for the
determination of oxidative stress levels/activities and lipid profile concentrations. Plasma glutathione peroxidase (GPx)
activity and 4-hydroxynonenal (4-HNE) level increased significantly, and the ratio of reduced glutathione (GSH) to
oxidized glutathione (GSSG) was decreased following 12-week interventions. Other enzymatic antioxidant activities such
as catalase (CAT) and superoxide dismutase (SOD) were increased, but the changes were not statistically significant.
Changes in plasma GPx activity were negatively correlated with changes in serum triglyceride (TG) and
VLDL-cholesterol concentrations. In conclusion, diet and exercise interventions in the 12-week behavioral lifestyle
modification program were effective in increasing antioxidant enzyme activities in obese adults.