Objective: The objective of this study was to examine the longitudinal relationship between the elapsed time in the action and maintenance stages of change for multiple target behaviors and weight loss or gain.
Research methods and procedures: The research design was a prospective cohort study of overweight and obese primary care patients randomized to an obesity management intervention based on the Transtheoretical Model and a chronic disease paradigm. The target behaviors included increased planned exercise and usual physical activity, decreased dietary fat, increased fruit and vegetable consumption, and increased dietary portion control. The participants were 329 middle-aged men and women with elevated body mass indices recruited from 15 primary care practices in Northeastern Ohio; 28% of the participants were African Americans. The main outcomes were weight loss (5% or more) or weight gain (5% or more) after 18 or 24 months of follow-up.
Results: There were significant (p < 0.05) longitudinal relationships between the number of periods (0 to 4) in action or maintenance for each of the five target behaviors, or a composite score taken across the five target behaviors, and weight loss. In all cases, there was a significant (p < 0.05) stepped (graded) relationship between the time in action or maintenance and weight loss (or gain).
Discussion: The data support the concept of applying the Transtheoretical Model to the problem of managing obesity in primary care settings. The remaining challenge is to identify those factors that reliably move patients into the action and maintenance stages for long periods.