Dietary assessment and physical activity measurements toolkit

Choosing a dietary assessment or physical activity assessment method

The selection of method(s) to measure diet or physical activity needs to be driven by the study design and the research question. Researchers need to carefully consider what aspect or aspects of diet or physical activity are central to the aims and the outcome measures of the study. It is essential to be clear about the primary outcome / exposure / confounder / covariate.
Bearing in mind there is no single ideal method for measuring diet or physical activity some fundamental questions should be carefully considered before making a decision on the assessment method.

1. What are the objectives of the research question?
2. What are the dietary or physical activity outcome measures that are central to the aims and outcome measures of the study?
3. What specific kinds of information are being sought e.g. nutrients and/or foods; ranking broad categories of physical activity or physical activity energy expenditure?
4. What resources are available both in terms of finance and manpower?
5. Are there special subject characteristics to be considered e.g. memory in the case of the elderly, literacy?
6. What type of analysis will the data be subjected?
7. What resources and experience are available for the analysis of the data?

A short food frequency questionnaire will not provide an estimate of energy intake and an individual level.  A physical activity questionnaire designed for surveillance purposes is not suitable to measure physical activity in a cohort study.  A researcher interested in obesity may be interested in the energetics of physical activity while a researcher in bone health may be interested in the biomechanical aspects of physical activity.
The aim of this section is to assist researchers choose the most appropriate method by clarifying the primary and secondary outcomes of the diet or physical activity assessment and providing guidance on methods that are suitable.  The choice of method will be dependent on practical considerations such as resources and the population understudy; the impact of these on the choice diet and physical activity assessment methods are provided.


For each of the diet and physical activity assessment methods there is a detailed section on the toolkit which should be read in conjunction with the matrices.
Users are advised to refer to the specific pages for each assessment method as well as reading the information provided in the matrices. 


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