Three questions guided a literature review of the transtheoretical model (TTM) as applied to exercise to address the evidence for stage-matched interventions, the description of priority populations, and the identification of valid TTM measurement tools. One-hundredand-fifty studies were reviewed. Results indicate preliminary support for the use of stage-matched exercise interventions. Most studies have focused on White, middle-class, female populations, limiting the generalizability of their findings. Valid and reliable measures exist for stage of change, decisional balance, processes of change, self-efficacy, and temptations to not exercise; however, more research is needed to refine these measures. Evidence for the construct validity of the TTM as applied to exercise is mixed. When designing and implementing TTM-based exercise interventions, practitioners and policy makers are encouraged to clearly define the term exercise, choose a valid and reliable staging tool, and employ all TTM constructs and not just stage membership.

Evidence for the validity of the TTM as it applies to tobacco use is strong and growing; however, it is not conclusive. Eight different staging mechanisms were identified, raising the question of which are most valid and reliable. Interventions tailored to a smoker's stage were successful more often than nontailored interventions in promoting forward stage movement. Stage distribution is well-documented for U.S. populations; however, more research is needed for non-U.S. populations, for special populations, and on other TTM constructs.

The transtheoretical model (TTM) is a behavioural theory that describes behaviour change as occurring in five stages, ranging from precontemplation to maintenance. The purpose of the present paper is to review and synthesise the literature published since 1999 on applications of the TTM to dietary behaviour so that the evidence for the use of assessment tools and interventions based on this model might be evaluated. Six databases were identified and searched using combinations of key words. Sixty-five original, peer-reviewed studies were identified and summarised in one of three tables using the following categories: population (n 21), intervention (n 25) and validation (n 19). Internal validity ratings were given to each intervention, and the body of intervention studies as a whole was rated. The evidence for using stage-based interventions is rated as suggestive in the areas of fruit and vegetable consumption and dietary fat reduction. Valid and reliable staging algorithms are available for fruit and vegetable consumption and dietary fat intake, and are being developed for other dietary behaviours. Few assessment tools have been developed for other TTM constructs. Given the popularity of TTM-based assessments and interventions, more research is warranted to identify valid and reliable assessment tools and effective interventions. While the evidence supports the validity of the TTM to describe populations and to form interventions, evidence of the effectiveness of TTM-based interventions is not conclusive. Transtheoretical model: Dietary behaviour: Nutrition behaviour: Weight management Introduced in 1981 1 , the transtheoretical model (TTM) has become one of the most popular and enduring theories in the field of health promotion and health education. The central concept within the theory is that behaviour change is most likely to happen when individuals engage in the right activities, or processes of change, at the right time, or stage. According to the theory, individuals are most likely to experience success in changing behaviour when they engage in strategies that are appropriate to their stage of readiness to make the change. It has been applied to diverse health behaviours, including the cessation of addictions, participation in cancer screening, and the adoption of positive lifestyle behaviours 2. Overview of the transtheoretical model Many published papers provide a detailed description of the TTM, therefore only a brief overview of the model is offered here. The TTM is comprised of the following constructs: stages of change, processes of change, decisional balance, self-efficacy, and temptation. Stage of change refers to the degree of readiness an individual exhibits toward adopting healthful dietary behaviours. A generalised version of the five stages has been identified and used to classify behaviour 3. The stages are: (1) precontemplation, in which an individual may or may not be aware that a behaviour change is warranted and has no intention of changing within the next 6 months; (2) contemplation, ...

The author collected data on serum cholesterol, blood pressure, and self-reported health behavior in 226 college students aged 18 to 26 years. Twenty-nine percent had undesirable total cholesterol levels, 10% had high cholesterol, 10% had high systolic blood pressure, and 11% had high diastolic blood pressure. Half or more of the participants consumed a diet high in saturated fats, engaged in binge drinking, had a parental risk for high cholesterol or blood pressure, or reported they experienced elevated stress levels. Men had higher risk-factor levels than women. Findings from a regression analysis revealed that smoking, binge drinking, lack of cardiovascular exercise, and eating a high saturated-fat diet were predictive of undesirable cholesterol levels. Study limitations included self-selection of participants and single measurements of blood pressure and cholesterol. Trained students served as screeners in the program for providing an effective, low-cost screening intervention.

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