Review of self-efficacy and locus of control for nutrition- and health-related behavior.

This article reviews several cognitive predictors of health- and diet-related behaviors commonly used in theories and models of nutrition and health behavior change. Constructs such as self-efficacy, self-esteem, outcome expectancies, health value, and locus of control are examined. Self-efficacy has repeatedly been a good predictor of health behavior, sometimes explaining more than 50% of variability. Research on locus of control and other predictive factors has been less conclusive. The take-home message is threefold: (a) task specificity of self-efficacy and domain specificity of locus of control are crucial for unraveling their effects on behavior; (b) careful segmentation of different population groups under study may explain the inconsistencies in previous research; and (c) especially when studying dietary behavior, these predictors of behavior change should not be used alone or in place of one another but should be used simultaneously to explain complex food and diet-related behaviors. We recommend that nutritionists systematically integrate available theories and models and explore new areas for studying human behavior, such as sociology and anthropology, to form a more powerful, comprehensive model for behavior change.