Information metabolism, sometimes referred to as informational metabolism or energetic-informational metabolism, is a psychological theory of interaction between biological organisms and their environment, developed by Polish psychiatrist Antoni Kępiński.

Kępiński described his psychological theory in several books but the most detailed description is given in his 1974 book Melancholy (in Polish: "Melancholia"). In order to explain psychological phenomena encountered in humans, he borrowed many concepts from the field of cybernetics which gained popularity in Poland at that time, thanks to the works of Marian Mazur (the father of the Polish school of cybernetics). Kępiński starts with the consideration of most basic organisms and how they are different from inanimate matter. First of all, any organism may be treated as an autonomous but open system, separated from its environment by means of a boundary (skin or cell membrane). As an open system, it is engaged in a continual exchange with its surroundings. That exchange may be regarded as twofold i.e. energetic and informational. For the sake of analysis, one may think of energy metabolism and information metabolism as separate processes. Kępiński postulates that life is sustained if both metabolisms are occurring, and it stops if one of them is ceased.

The energy metabolism concept is relatively easy to understand. The molecules of the body are continually replaced. Catabolic and anabolic processes occur in cells. Information metabolism is the other side of the same process, but it concerns the structural aspect (i.e. how matter and energy are organized) and how control is executed. During energy exchange, the organism strives to maintain its characteristic order (negentropy) and projects that order onto the surroundings. As a result, the order of the surroundings is destroyed. By contrast, inanimate matter does not have the ability to raise or even maintain its negentropy, because spontaneous natural processes are always accompanied by entropy generation.

Information metabolism may be generally seen as the exchange of signals between the organism and its environment, but also as the processing of signals originating in the organism. These signals must be interpreted in relation to some goals. For all organisms these goals are predicated on two biological laws: the first law states that an organism must be oriented towards its own survival. The second law states that the preservation of the species is equally important. Kępiński noticed that these objectives are conflicting. The conflict between the two biological laws is often the source of ethical dilemmas. There are times when the organism needs to sacrifice its life in order to save its offspring. Sometimes it is forced to fight with the representatives of its own species, in order to protect itself. The first biological law is egoistic and related with withdrawal from reality (escape, destruction of reality etc.). The second biological law is altruistic and requires turning towards the reality (sexual reproduction requires union with the partner).

In case of humans, the connection between the goals of various everyday actions and two biological laws is less direct, nevertheless these laws still motivate us. Humans are able to project themselves into the future, think abstractly and consciously and therefore their goals may possess transcendent and symbolic character. This fact is typically expressed as belief in a higher good or an afterlife.

It is impossible to keep track of all information generated by various processes occurring in reality. As organisms strive to fulfill two biological laws, proper selection of signals becomes a central problem. According to Kępiński, a hierarchy of value is necessary in order to integrate information. In humans, that hierarchy comprises three levels i.e. biological, emotional and sociocultural. The first two levels are handled subconsciously. The third level, by contrast, is associated with consciousness. From the biological perspective, the number of processes occurring simultaneously in the organism and its physical surroundings is virtually infinite. There is also infinite number of ways in which these processes may be framed. That complexity must be reduced, as only selected signals may be sensed and processed in the nervous system. Moreover, the signals must be ordered according to their present and future relevance. The structure of the body and locations of various receptors are evolutionally adapted to assure isolation of the most relevant signals from the surrounding environment. The internal structure of the body is adjusted to ensure proper integration of information. Of all signals collected by the receptors, only the most important ones reach the level of subjective experience. At the level of signals reaching the field of subjective experience, attention is actively directed (with the help of emotions) towards those related with two biological laws. Perception is not passive and inclusive, but anticipatory and selective. Above biological and emotional levels of signal interpretation, there is the frame of social and cultural norms of the community, which serves as reference for conscious decisions. The sociocultural background plays significant role in people's lives.

The division of information metabolism into two phases is loosely based on the analysis of the orienting response. Information metabolism is initiated by the perception of a change in the internal or external environment of the organism. In the first phase, the organism seeks to obtain direct information about the perceived phenomenon. Because of that, it must turn its attention 'outside' to the reality. The perceived phenomenon is then subconsciously evaluated. The result of that evaluation manifests itself as an emotion. The sign of the invoked emotion may be positive or negative. This emotion, arising quickly and automatically, serves as the background for the second phase of information metabolism.

In the second phase, the organism executes a locomotor reaction to the phenomenon. Motion towards the source of the stimulus is performed if the stimulus signifies a positive possibility. If the stimulus was evaluated negatively in the first phase, then it is likely that the executed reaction will take the form of escape, fight or immobilization. During the second phase, the organism is primarily occupied by its own actions. It observes their effect and makes adjustments (which forms a feedback loop). Despite the feedback, its connection with reality is less intensive than during the first phase. The separation from reality in the second phase of information metabolism is greater in complex animals and reaches its maximum in humans.