Oral lipid‐based nutritional supplements (LNS) are designed to ensure dietary adequacy and to improve malnourishment in children. Therefore, this study investigated the effects of 4 weeks of LNS on appetite, energy intake, and lipid profile of moderately underweight children (5–10 years old) with BMI‐Z score between −2 and − 3 SDS, recruited in a single‐blind randomized control trial. In addition to the regular dietary intake, fasting blood samples, anthropometric measurements, energy intake, and appetite responses were obtained before and after 4 weeks of LNS (535 kcal) or PLACEBO (92 kcal). After 4 weeks of supplementation mean energy intake (kcal) (
p
< .001), body weight (kg) (
p
< .001), BMI (kg/m
2
) (
p
< .01), mid‐upper arm circumference (cm) (
p
< .01), total cholesterol (mg/dl) (
p
< .01) and fasting glucose (mg/dl) (
p
< .01) were raised significantly in the LNS group as compared to the PLACEBO group. No significant changes were detected in appetite responses (p > 0.05). In conclusion, LNS increases the overall energy intake, but does not affect the appetite but may induce hyperglycemia and hyperlipidemia.