The fat burning analyser comprises at least a sampling part, an analysis unit and a processing unit. The sampling part is equipped for collecting a breath sample from the user. Furthermore, the sampling part is equipped for collecting information on the conditions of the breath sample collection. Additionally, the sampling part is equipped to provide a sampling signal correlated to the collection condition of the breath sample. The analysis unit is equipped to provide a detection signal corresponding to an acetone concentration in the collected breath sample. As the detection signal corresponds to the acetone concentration in the breath sample the analysis unit provides information on the breath acetone of the user (during exercise or resting). The processing unit is equipped to receive the sampling signal and/or detection signal. Furthermore, the processing unit is equipped to evaluate the sampling signal and/or the detection signal. The evaluation provides information correlated to the fat burning intensity of the user. These information can be provided as an output signal by the processing unit. Accordingly, the processing unit is equipped is equipped to provide an output signal correlated to the fat burning intensity of the user.
