The study will conform to a randomised mixed design. Both the diabetic experimental group and the control group will take part in three conditions whereby participants will receive a high GI, a low GI, or a water breakfast delivered in a counterbalanced order. Participants will then perform the battery of cognitive tests on 2 occasions throughout the morning; 30 minutes after breakfast and 180 minutes after breakfast. Blood glucose will be measured from capillary finger-prick blood samples using diabetic glucose meters throughout the morning.