The increasing number of network attacks causes growing problems for network operators and users. Thus, detecting anomalous traffic is of primary interest in IP networks management. In this paper we present a novel method for network anomaly detection, based on the idea of discovering Heavy Change (HC) in the distribution of the Heavy Hitters in the network traffic. To assess the validity of the proposed method, we have performed an extensive experimental evaluation phase, during which our system performance have been compared to a more "classical" HC-based approach. The performance analysis, presented in this paper, demonstrates the effectiveness of the proposed method.