N09001: A family-based study to determine the acceptability of an increased intake of complex carbohydrates and explore how change can be achieved

Study Duration: September 1997 to June 2002

Contractor: University of Newcastle upon Tyne

This project aims to identify important factors which influence consumer choice of foods rich in complex carbohydrates. It will examine factors at the family level, individual level and different age and gender groups. It will determine the palatability and acceptability of foods high in complex carbohydrates. The project will identify the most effective method for encouraging consumers to eat more foods rich in complex carbohydrate and how an increase in complex carbohydrates effects the total diet composition.

The results will be translated into advice for consumers and food manufacturers.

The objectives of this research project are to:

• Identify and determine the relative importance of factors influencing consumer choice of foods rich in complex carbohydrates at a family level, an individual level and for different age and gender groups.
• Determine the palatability and acceptability, on initial exposure and at three months, of a range of foods high in complex carbohydrates at a family level, an individual level and for different age and gender groups.
• Determine the process of the change and effectiveness of each of three approaches in encouraging customers to eat more foods rich in complex carbohydrates. The three approaches to be tested are:
  (a) an increased awareness of foods rich in starch by risk free trial of foods high in starch;
  (b) new or improved cooking skills for starchy foods and confidence in their application;
  (c) intensive intervention (a plus b plus individualised dietary advice).
• Measure the effects of the three approaches indicated in scientific objective 3 on consumers' choices (at family and individual level) of foods rich in complex carbohydrates, on total diet composition (in particular % energy from fat) and intakes of other nutrients.
• Measure the sustained effects of the three approaches of objective 3 on consumers' choices of foods rich in complex carbohydrates, on total diet composition and intakes of other nutrients at 6 months post intervention and at 18 months post intervention.
• Make recommendations for the application of the findings in advice to consumers and in guidance to food manufacturers and retailers in the light of results of assessments at baseline and at 3, 6 and 18 months post intervention.

Newcastle families (any number of adults living with at least one child under age of 16 years), living in enumeration districts (ED) in the middle three quintiles of the Townsend Deprivation Index who do not meet dietary targets for fat (<35% energy) and starch (>29% energy) have been recruited and randomly allocated (by ED) to one of three interventions designed to encourage and enable them to choose diets richer in starchy foods. The interventions are designed to test the hypothesis that a more positive message to eat more (low fat) starchy foods would be better received than a message to eat less fatty foods and so achieve the desired dietary goals.

• Intervention A is a one-off family health event designed to be interactive and provides plans for personal change, recipes and food samples to eat and to try at home.
• Intervention B is a series of four cooking groups for adults (plus separate single session for children).
• Intervention C invites families to participate in all intervention A and B events and receive individualised dietary advice based on baseline food diaries.

Data collection includes anthropometric measurements, 3-day dietary diaries followed by interview, an assessment of knowledge of starchy foods, and a questionnaire. The questionnaire includes both qualitative and quantitative questions constructed to gather contextual, knowledge and attitudinal data on issues pertinent to dietary change. Psychological models which may be predictive of change and demographic data questions are also included. Data have been collected at baseline, 3 months, 6 months and 18 months following the intervention. Information on the acceptability of the interventions is also being gathered. A sub-sample of families has been selected at random for in-depth interview (at baseline and 3 months ). Interviews explore early life influences and the decision-making process for food choice within the family. An aim is not only to measure any dietary change which may occur, but also to determine the process of change by which consumers adapt a diet high in complex carbohydrates.

A total of 206 families (709 individuals) completed baseline food diaries of which 27 families were already meeting the dietary targets for fat and starch. Baseline and 3 month data were collected from 176 families who completed the intervention. Six month and 18 month data have also been collected.

A subsidiary study has measured the initial acceptability of foods rich in starch. Members of 77 families (186 individuals) were recruited, using the method outlined above, to take part in sensory evaluation. Subjects used visual analogue scales to assess the sensory attributes of different forms of bread, pasta and potato.

206 Newcastle families completed baseline (T0) assessment of their diets using a three-day diet diary.

172 families with mean intakes of more than 35% food energy from fat and less than 29% food energy from starch were allocated to one of three interventions:

• Intervention A: 'Health Fayre' – information-based intervention
• Intervention B: 'Cook and Eat' – skills and information
• Intervention C: 'Intensive' – components of Interventions A and B plus personalised advice

Quantitative data on dietary behaviour outcomes were obtained at 3 months (T1), 6 months (T2) and 18 months (T3) after the end of the interventions. In addition, information about knowledge of healthy eating, attitudes to starchy foods and shopping habits, for example, were collected by questionnaire at each time point. A sub-set of families was interviewed to help inform understanding of barriers to change and how these might be overcome.

Key findings

• All interventions resulted in increases in starch intake and reductions in fat intake. At T1, the percentage of food energy from starch was 2.5% units higher and the percentage of food energy from fat 1.5% units lower than at T0 for intervention families. By T2 and T3 these changes were maintained but at lower levels than at T0.
• Changes in diet tended to be greater for adults than for children and greater in women than in men.
• Overall, Intervention B tended to be the most effective in the longer term in eliciting the desired changes.
• Participants in the study did not perceive starchy foods as a coherent food group (unlike the case for fruits and vegetables) nor had they a good understanding of role of starchy foods in healthy diets.
• The 'myth' that starchy foods are fattening persists.

This suggests that a positive message, e.g. 'eat more starchy foods', may be effective in lowering fat intake. However, the public's poor understanding of starchy foods as a group and the confusion about their place in a healthy diet remains a considerable barrier.

Final report is available from the FSA Library and Information centre.
To obtain a copy, please contact the Enquiry Desk, Dr. Elsie Widdowson Library and Information Services, Food Standards Agency (020 7276 8181/8182 or at infocentre@foodstandards.gsi.gov.uk).

Loughridge, J.L., Beard, C.M., Adamson, A.J. and Mathers, J.C. Bear-ing it all. Starting with starch. Article in British Dietetic Association Advisor magazine Winter 1998.

Spendiff, A. and Stacy, R. Factors affecting the consumption of starchy foods: a model derived from qualitative data. Oral presentation at the 28th Annual Scientific meeting of the Association of University Department of General Practice. London, July 1999.

Denby, N., Adamson, A.J., Curtis, P.J. and Mathers, J.C. What are starchy foods? Poster presentation at the XIIIth International Congress of Dietetics. Edinburgh, July 2000.

Adamson, A.J., Curtis, P.J., Loughridge, J., Rugg-Gunn, A., Spendiff, A., Mathers, J.C. (2000). A family-based intervention to increase consumption of starchy foods. Nutrition and Food Science, 30 19-23.

Mathers, J.C. (2000). Dietary strategies to reduce the burden of cancer and cardiovascular disease in the UK. British Journal of Nutrition 84, S211-S216.

Curtis, P.J., Adamson, A.J. and Mathers, J.C. (2001). The relationship between starch and fat consumption in a UK population. Proceedings of the Nutrition Society 60, 70A.

Adamson, A.J., Spendiff, A., Curtis, P.J., Jones, A., Mathers, J.C. (2001). Relationship between consumer attitudes to starchy foods and starch consumption. Proceedings of the Nutrition Society 60, 184A.

Tohill, U.R., Curtis, P.J., Adamson, A.J., Mathers, J.C. (2001). Individual's perception of diet with regard to health compared with recorded intake. Proceedings of the Nutrition Society 60, 181A.

Curtis, P.J., Adamson, A.J., Mathers, J.C. (2001). Associations between fruit and vegetable, starch and fat consumption? Proceedings of the Nutrition Society 60, 183A.

Stacy, R., Spendiff, A. and Adamson, A. Dietary change and perceptions of self: a qualitative study. Oral presentation at the 30th Annual Scientific meeting of the Association of University Departments of General Practice, University of Leeds, July 2001.

Carlin, L., Tohill, U.R. and Adamson, A.J. Who, me? Participation in a dietary intervention program. Presented at the American Anthropological Associations 100th Annual meeting. Washington DC. Dec 2001.

Curtis, P.J., Webster, S., Adamson, A.J., and Mathers, J.C. (2002). Parental change in starch and fat Intake after a "Starchy Food" intervention. Proceedings of the Nutrition Society 61, 106A.

Invited keynote lecture to British Dietetic Association Conference June 2003 - Dr Ashley Adamson, The Family, Food and Health project.

Contact: For any enquiries concerning this research project, please contact science@foodstandards.gsi.gov.uk