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

Introduction 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. Department of Health Education and Promotion, University of Maastricht, PO Box 616, 6200 MD Maastricht, The Netherlands The relationship between the consumption of fruit, vegetables and fat, and the prevention of numerous diseases has become more explicit in recent years. Many studies have shown that people with moderate to high consumption of fruit and vegetables have a lower risk of several kinds of cancer, cardiovascular diseases, hypertension and stroke (Gerster, 1991; Weisburger, 1991; Block et al, 1992; Hertog et al, 1993). Consumption of high fat diets, especially diets high in saturated fats, is considered a risk factor for a number of chronic diseases like cardiovascular diseases, various kinds of cancer, diabetes mellitus and obesity (Dutch Nutrition Council, 1986, 1991; Surgeon General, 1988; National Research Council, 1989). Increased knowledge of the health effects of fruit, vegetables and fat intake has led to the development of guidelines for daily intake. The Netherlands Bureau for Food and Nutrition recommends adults eat three to four serving spoons (approximately 150-200 g) of vegetables and two pieces of fruit (approximately 200 g) per day (Netherlands Bureau for Food and Nutrition Education, 1993). Also, the Dutch Nutrition Council recommends adults reduce their dietary fat intake to 35% or less of total calories, especially by reducing intake of saturated fat (Dutch Nutrition Council, 1986, 1991). Only a small proportion of the Dutch population eats according to these guidelines (Hulshof et al, 1994). Health education interventions aimed at increasing fruit and vegetable consumption and decreasing fat intake are therefore necessary. Health education interventions aimed at chan© Oxford University Press by gest on Jauary 3, 2012 http://herrdjournals.org/ D ow nladed from