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Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet]. York (UK): Centre for Reviews and Dissemination (UK); 1995-.

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Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet].

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Synthesis of intervention research to modify physical activity and dietary behaviors

and .

Review published: .

CRD summary

This descriptive review explored conceptual and methodological issues of studies to improve both physical activity and dietary behaviour. The authors concluded, to a varying degree, that the interventions were effective in those who completed the programme. Methodological shortcomings in the review process undermine the reliability of the review findings.

Authors' objectives

To examine, through the use of a descriptive review, the conceptual and methodological issues of interventions designed to improve both physical and dietary behaviour.


CINAHL (1994 to 2004), MEDLINE (1997 to 2004) and PsycINFO (1966 to 2004) were searched for articles published in English between 1993 and 2003; the search terms were reported. The reference lists of retrieved articles were also checked.

Study selection

Study designs of evaluations included in the review

Explicit inclusion criteria for the study design were not defined. Randomised controlled trials (RCTs) and quasi-RCTs were included. The participants were randomised at a group or individual level.

Specific interventions included in the review

Studies that included both physical activity and dietary behaviour in naturalistic settings were eligible for inclusion. All interventions were defined as complex and included an educational and a behavioural change component. Some studies were guided by explicit theoretical models. The control interventions were usual care, self-help guides, waiting-list control and no treatment. Components of the intervention were categorised as education to change knowledge or attitudes; behaviour change strategies to overcome barriers or facilitate behaviour change; social strategies to provide support or a supportive environment; or organisational strategy. The interventions were administered in individual or group sessions for a duration of 5 months to 5 years, and the intensity of them varied between 42 and 52 sessions.

Participants included in the review

Studies of healthy adults, aged 18 years or older, were eligible for inclusion. Details of gender, age, ethnicity, and profession or social status were reported, along with characteristics of individual and environmental factors that might influence change. The included studies were conducted in communities, worksites, weight-loss or medical clinics, or a combination of these.

Outcomes assessed in the review

Explicit inclusion criteria for the outcomes were not reported. The included studies assessed the effectiveness of the intervention in relation to diabetes prevention, weight loss, hypertension prevention, or general healthy behaviours to prevent chronic illness, mainly using self-reporting questionnaires or diet and physical activity diaries. Details of the reliability and validity of outcome measures used in each individual study were reported.

How were decisions on the relevance of primary studies made?

The authors did not state how the papers were selected for the review, or how many reviewers performed the selection.

Assessment of study quality

A detailed assessment of the internal validity of each included study was undertaken. The criteria considered in the validity assessment related to study design, relevance of the intervention, components of the intervention, integrity of the intervention, reliability of the chosen outcome measure, and adherence and retention. The authors did not state how the validity assessment was performed.

Data extraction

The authors did not state how the data were extracted for the review, or how many reviewers performed the data extraction.

Methods of synthesis

How were the studies combined?

The synthesis was driven by a published framework recommended for the evaluation of intervention processes (see Other Publications of Related Interest). The studies were combined in a narrative and vote counting was used to synthesise the characteristics of the included studies. The studies were combined according to intervention description; research design; samples size and demographic data; relevance of intervention to the targeted outcome; intervention component; complexity, strength and integrity of the intervention; theoretical components of the intervention; expected intervention outcomes; reliability and validity of the outcome measures; extraneous factors; adherence to the interventions and retention; and effectiveness of the intervention.

How were differences between studies investigated?

Differences between the studies were apparent from the narrative synthesis and tables.

Results of the review

Seventeen studies (n >11,600) were included in the review.

Ten studies used a standardised curriculum, computer or written documents to deliver the intervention, while 13 used a professional. Eight studies used a standardised method to determine physiological markers of disease and most used anthropometric assessment. Most studies of physical activity and dietary behaviour used valid outcome measures. Eight studies reported adherence and 15 reported retention. Further details were given in the report.

Eleven studies showed that the intervention was effective in achieving the outcome of the study. The authors stated that it was not possible to determine the specific elements of these studies that contributed to the effectiveness, although effectiveness did not appear to be associated with the number of components, intensity or duration of an intervention.

Authors' conclusions

Overall, to varying degrees and for those completing the programmes, the interventions were effective in increasing physical activity, lowering dietary fat, weight loss, and reducing the risk of illness.

CRD commentary

This review aimed to provide a descriptive review to explore the conceptual and methodological issues of interventions aimed at improving both physical activity and dietary behaviour and, as such, the inclusion criteria were broadly defined. Several relevant sources were searched for studies, although the restriction to those reported in English will have introduced language bias. It is also noteworthy that the search was for studies published up to December 2003, thus this review may be in need of an update. Details of the review process were not reported, so reviewer error and bias cannot be ruled out. In line with the aim of the review, a thorough assessment of the internal validity of the studies was undertaken and reported clearly, and pertinent issues were highlighted for the development of interventions and future research. The review focused on process rather than outcome, thus a limited synthesis on the effectiveness of the interventions was performed.

This review provides a useful summary of the conceptual and methodological issues of studies in this area, and hence provides a guide for future practice and research. However, the aforementioned methodological shortcomings in the review process undermine the reliability of the review findings.

Implications of the review for practice and research

The authors stated that the overarching lesson is to focus on process evaluation (internal validity) and to decompose interventions. The authors identified 12 elements for consideration in future practice and research: the use of an explicit theoretical framework; explicitly defined problem and components of the intervention which are relevant to the problem; feasible and practical for use in a clinical setting; targeted to allow participants to decide on a strategy that suits; a focus on health pedagogy to concentrate on individual differences; moderating variables and extraneous factors should be reported and measured; recruitment and retention of the participants; the amount and duration of effective components should be identified and reported; positive and negative effects should be measured and reported; specific components of interventions that are effective should be reported; the inclusion of dependent measures that are reliable and valid; and the design of interventions that are sustainable. Priority should be given to the incorporation of theory to reveal the intervention content and mechanisms to modify physical activity and dietary behaviours concurrently, to ensure future interventions are more efficacious and efficient.


Indiana School of Nursing; National Institute of Nursing Research.

Bibliographic details

Blue C L, Black D R. Synthesis of intervention research to modify physical activity and dietary behaviors. Research and Theory for Nursing Practice 2005; 19(1): 25-61. [PubMed: 15989166]

Other publications of related interest

Sidani S, Braden CJ. Evaluating nursing interventions: a theory-driven approach. Thousand Oaks (CA): Sage; 1998.

Indexing Status

Subject indexing assigned by NLM


Attitude to Health; Diet, Fat-Restricted; Dietary Fats /adverse effects; Exercise; Food Habits; Health Behavior; Health Education /organization & administration; Health Knowledge, Attitudes, Practice; Health Promotion /organization & administration; Health Services Needs and Demand; Humans; Intervention Studies; Life Style; Outcome and Process Assessment (Health Care); Patient Compliance /psychology /statistics & numerical data; Randomized Controlled Trials as Topic; Research Design; Risk Factors; Risk Reduction Behavior; Sample Size; Weight Loss



Database entry date


Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.

Copyright © 2014 University of York.
Bookshelf ID: NBK71896


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