The use of the internet in all areas of life is beginning to have a clear impact upon the way in which dietary assessment is carried out. JHND is currently publishing a number of validation studies for web-based tools. My personal interest in this is mounting as recent undergraduate projects in my own department have highlighted the utility of web-based survey tools to reach very large numbers of potential participants, in a short space of time and at negligible cost. The limitations of the web for recruitment require further consideration, particularly around selection bias and the veracity of participant responses and fit with eligibility criteria.
The paper by Hutchesson and colleagues reports the findings of a pilot study examining the use of a web based tool for assessing energy intake. The researchers recruited 12 obese and overweight women to complete the SP Health Weight Loss Platform tool for 9 days, alongside measurements of total energy expenditure using doubly labelled water. Overall the agreement between the two methods at the individual level was poor, but for the whole group of subjects was approx. 80% which compares quite favourably with paper-based methods.
The study highlights that, although problems of underreporting by overweight participants clearly remain, the use of web based tools is at least as accurate as existing food record approaches. Web-based assessment allows for simple recording of food and beverage intake, with a low respondent burden and simplified analysis for researchers. When coupled to suitable platforms that support weight-loss programmes, the technique can give subjects feedback in real-time which can reinforce positive behaviours.