NC: Behavior Change Theories (2007-2008)
Behavior change theories or models are used to design and implement nutrition interventions. Theories and theoretical models consist of principles, constructs and variables, which offer systematic explanations of the human behavior change process. Behavior change theories and models provide a research-based rationale for designing and tailoring nutrition interventions to achieve the desired effect. Theories and models guide determination of:
- What information patients/clients need at different points in the behavior change process
- What tools and strategies may be best applied to facilitate behavior change
- Outcome measures to assess effectiveness in interventions or components of interventions
The Nutrition Counseling Evidence Analysis Project explored the evidence related to the following theories/models and nutrition therapy:
- Cognitive-Behavioral Therapy (CBT) - is based on the assumption that all behavior is learned and is directly related to internal factors (e.g., thoughts and thinking patterns) and external factors (e.g., environmental stimulus and reinforcement) that are related to the problem behaviors. Application involves use of both cognitive and behavioral change strategies to effect behavior change.
- Transtheoretical Model - A theoretical model of intentional health behavior change that describes a sequence of cognitive (attitudes and intentions) and behavioral steps people take in successful behavior change. The model, developed by Prochaska and DiClemente, is composed of a core concept known as Stages of Change, a series of independent variables, the Processes of Change, and outcome measures including decision balance and self-efficacy. The model has been used to guide development of effective interventions for a variety of health behaviors.
- Social Cognitive Theory/Social Learning Theory - provides a framework for understanding, predicting, and changing behavior. The theory identifies a dynamic, reciprocal relationship between environment, the person, and behavior. The person can be both an agent for change and a responder to change. It emphasizes the importance of observing and modeling behaviors, attitudes and emotional reactions of others. Determinants of behavior include goals, outcome expectations and self-efficacy. Reinforcements increase or decrease the likelihood that the behavior will be repeated.
Evidence related to these theories was explored for the following conditions:
- Cardiovascular disease
- Weight management
- Diabetes management
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Summary of Findings
Behavior Change Theory Evidence as it Relates to Nutrition Counseling
Eighteen positive quality RCTs, five neutral quality RCTs, two neutral quality non-randomized trials and two neutral quality quasi experimental studies provide evidence that Cognitive Behavioral Therapy (CBT)is beneficial in facilitating modification of targeted dietary habits (e.g., decreased calories from fat, decreased sodium, increased intake of fruits and vegetables), weight, and cardiovascular and diabetes risk factors. Evidence is particularly strong in patients with type 2 diabetes receiving intensive, intermediate-duration CBT (6-12 months in duration), and long-term (> 12 months duration) CBT targeting prevention or delay in onset of type 2 diabetes and hypertension. The workgroup answered 12 questions related to CBT.
One positive quality RCT supported the application of the Transtheoretical Model to improve health and food behavior change. Most research to date has been to validate instruments to measure diet-related stage of change rather than testing the efficacy of the model to change behavior. The workgroup answered 1 question related to the Transtheoretical Model
Two small RCTs (one positive and one neutral quality) assessed the effectiveness of nutrition counseling utilizing strategies based upon Social Cognitive Theory and failed to show clear effect. Additional studies of increased intensity are needed to better explore application of this theory in the nutrition therapy. The workgroup answered two questions related to Social Cognitive Theory.