Stages of change for fruit, vegetable and fat intake: consequences of misconception

In order to study whether the Stages of Change concept of the Transtheoretical Model is applicable to fruit, vegetable and fat intake, data on two different study populations were analysed. Two methods of classifying stages of change were compared in both study populations. The first, more traditional, classification method was based on intentions and self-rated intake. In the second classification method, estimated level of consumption (using a food frequency questionnaire) of fruit, vegetables and fat was included. Differences between both classification methods in distributions of respondents over stages of change were large, especially for vegetable and fat intake. Many subjects who were in maintenance based on the traditional classification method were classified in the precontemplation stage if the alternative classification method was used, since these subjects were unaware of their unfavourable dietary intake. Nutrition education that uses the Stages of Change as a base for developing educational messages should not provide these subjects with information aimed at sustaining the present behaviour but with information that creates awareness of personal dietary behaviour. Considerations should be given to including more objective behavioural assessment methods in Stages of Change classification methods when the Transtheoretical Model is applied to nutrition research.