BACKGROUND: Childhood obesity is a leading health concern. We have previously demonstrated the effectiveness of a restricted-carbohydrate, unlimited energy diet for weight reduction in elementary school-aged children. To our knowledge, there are no studies that have looked at the effect of this diet on lipid profiles in elementary school-aged children. Therefore, the objective of this pilot study was to examine the effect of a restricted-carbohydrate, unlimited protein, unlimited energy diet on lipid profiles in obese children 6 to 12 years of age. METHODS: Overweight children (body mass index >97%) referred to our obesity clinic were treated with a restricted-carbohydrate (<30 grams daily), unlimited protein, and unlimited energy diet. Weight, height, body mass index, and fasting lipid profiles were obtained at baseline and at 10 weeks on each patient. RESULTS: Twenty-seven patients were enrolled in our study, with a total of 18 patients returning for our 10 week follow-up (67%). The study group included 10 males and 8 females, with an age range of 6 to 12 years. Both total serum cholesterol and triglyceride levels showed a significant reduction; 24.2 (P = 0.018) and 56.9 (P = 0.015) mg/dL, respectively. CONCLUSIONS: We have demonstrated a significant decrease in total cholesterol and triglycerides in elementary school-aged children after 10 weeks of a restricted-carbohydrate, unlimited protein, and unlimited energy diet. We suggest that this diet may decrease cardiovascular risk factors in obese children. Long-term studies will be needed to substantiate these data.