A metabolic disorder can occur if the processes of conversion and utilization of individual building blocks and nutrients mentioned above come to a standstill or do not function correctly. This can mean that the required substances do not get to where they are needed in the body or the processing of individual important nutrients is disrupted. Diffuse, long-lasting symptoms, such as persistent exhaustion, lack of energy, problems concentrating, problems with the digestive tract, a weak immune system, recurring infections or persisting obesity or a sudden change in body weight can be indications of a metabolic disorder.