Assessing Intentions to Eat Low-Glycemic Index Foods by Adults with Diabetes Using a New Questionnaire Based on the Theory of Planned Behaviour

Abstract Objective The Canadian Diabetes Association recommends that people with diabetes choose foods with low-glycemic index (GI). This study developed a questionnaire measuring Theory of Planned Behaviour (TPB) constructs relative to consuming a low-GI diet by people with diabetes so as to achieve a better understanding of which TPB constructs, demographic characteristics and diabetes-related variables best predict intention to consume a low-GI diet. Method A questionnaire to measure intentions to consume a low-GI diet was developed based on TPB constructs and was administered to 369 adults (30 to 75 years) with type 1 or type 2 diabetes. Responses were analyzed using multiple linear regression. Results More than 90% of participants (mean age, 56.5±10.8 years; mean body mass index, 30.5±7.2 kg/m2 ) cited reduction and maintenance of healthy blood glucose levels as an advantage of eating low-GI foods. Older age, higher income, female gender, having type 2 diabetes, diabetes treatment (diet only) and understanding of the GI were positively associated with intention to eat a low-GI diet. TPB constructs that significantly predicted intentions to eat a low-GI diet were instrumental attitude (beta = 0.24, p