Dietary Perceptions in People with Type 2 Diabetes: Accuracy of Estimated Dietary Intake and Perception of Healthy and Unhealthy Foods

Abstract

Misperception of one’s dietary intake is one of many barriers to dietary behaviour change. Those who have a falsely optimistic perception of their dietary intake are less likely to intend to improve their current behaviours. The accuracy of perceived intakes of common carbohydrate-containing foods is of particular importance for people with type 2 diabetes, given the importance of dietary management in achieving glycaemic control. There is evidence to suggest that perceived intakes of some foods are less accurate in people with type 2 diabetes, however the accuracy of their perceived intakes of common carbohydrate-containing foods have not been investigated.

Perceptions and beliefs regarding the healthiness of foods also influence dietary behaviours. Once again, these perceptions have not been well explored in people with type 2 diabetes. The aim of this study therefore was to investigate the accuracy of perceived intakes of common carbohydrate-containing foods and perception of the healthiness and unhealthiness of foods in New Zealand adults with type 2 diabetes.

In the first part of this study (quantitative component) the accuracy of perceived intakes were assessed in twenty-four participants. Participants completed a seven-day food diary, followed one month later by a short interview which included a tool that measured participants’ perceived intake of common carbohydrate-containing foods. Data from each of these measurements were then compared to determine the accuracy of their perceived intake, compared to their actual intake.

Participants’ perceived intake of grains, fruit, dried fruit, scones/pikelets/sweet buns/cheese puffs, pies/pastries/savouries and biscuits/crackers were significantly different to their actual intake of these foods. Furthermore, perceived intakes of fruit, dried fruit and pies, pastries and savouries were falsely optimistic. Participants perceived they ate 6.0 (3.2 – 8.8) servings more of fruit, 1.4 (0.4 – 2.4) servings more of dried fruit and -2.3 (-3.8 – -0.8) servings less of pies, pastries and savouries compared to their actual intake, per week.

In the second part of this study (qualitative component) perceptions of the healthiness and unhealthiness of foods were investigated in twelve participants. Participants attended one of three ninety-minute focus groups to discuss their perceptions. Thematic analysis was applied to analyse the findings from these discussions and four themes were identified; Perceptions of Food Components; Other Factors Perceived to Influence the Healthiness of Foods; Perceptions of Dietary Information; Challenges to Forming Accurate Perceptions. Participant perception of foods was largely consistent with dietary guidelines with the exception of some foods that are advised in moderation. Participants placed a great amount of importance on the carbohydrate content of foods which compromised their perception of some healthful foods such as fruit and starchy vegetables.

The results from this study provide insight into different dimensions of dietary perceptions in people with type 2 diabetes living in New Zealand. These findings highlight a number of requirements for achieving effective dietary management of people with type 2 diabetes. These requirements include increasing the accuracy of perceived intake, clarifying guidelines around foods advised in moderation and managing nutritional priorities, other than the carbohydrate content of foods.