Provided are a melanine-concentrating hormone receptor antagonist composition, a use for the composition for inhibiting the binding of melanine-concentrating hormone to a receptor therefor, and a method for inhibiting the binding of melanine-concentrating hormone to a receptor therefor. It was discovered that a specific cyclic dipeptide or a salt thereof has a melanine-concentrating hormone receptor antagonist effect. The present invention provides an effective and novel means that contributes to the enhancement of various physiological activities such as weight gain resistance.