Which of the following is NOT one of the six key constructs influencing behavioral change?

The construct that does not belong to the recognized key constructs influencing behavioral change is external motivation. The established constructs that are typically associated with influencing behavior change include perceived susceptibility, perceived severity, and self-efficacy.

Perceived susceptibility refers to an individual's belief about the likelihood of experiencing a health problem, which can motivate changes in behavior to reduce that risk. Perceived severity relates to the individual's feelings on the seriousness of the health issue, which can also drive the urgency to change behaviors for better health outcomes. Self-efficacy, on the other hand, involves an individual’s confidence in their ability to perform behaviors necessary for good health, which is crucial for motivating sustained behavior change.

External motivation, while it can play a role in influencing behavior through incentives or pressures from outside sources, is not identified as one of the primary constructs that form the foundational theories used to understand and promote behavior change in the context of lifestyle medicine. Therefore, its absence in the list of key constructs marks it as the correct choice in this scenario.