Canadian Trial of Dietary Carbohydrates in Diabetes

Long-Term Effect of Altering the Source or Amount of Dietary Carbohydrate in Type 2 Diabetes

A long-term low carbohydrate, high monounsaturated fat diet, compared to a high carbohydrate, low glycemic index diet, results in more rapid progression of diabetes; i.e. increased fasting glucose and glycated hemoglobin, reduced beta-cell function and insulin sensitivity and increased free fatty acids. The deleterious effects of a high carbohydrate diet on plasma lipids are only temporary and do not persist beyond 6 months. A long-term high carbohydrate, low glycemic index diet, compared to a high carbohydrate, high glycemic index diet, improves glycemic control and beta-cell function

Inclusion Criteria:

• male or non-pregnant/non-lactating females with type 2 diabetes treated by diet alone
• age 53-75y
• body mass index 25-40kg/m^2 (Caucasian) or 23-40kg/m^2 (other)
• HbA1c <=130% of upper limit of normal of local hospital lab

Exclusion Criteria:

• use of any hypoglycemic or anti-hyperglycemic drug within 6 months of randomization
• major cardiovascular event or major surgery within 6 months of randomization
• serum triglycerides >10mmol/L
• presence of other major debilitating disorder such as liver disease, renal failure or cancer
• presence of gastrointestinal disorder or use of drug which is likely to alter gastrointestinal motility or nutrient absorption
• use of oral steroids
• substance or alcohol abuse
• simultaneous participation in another clinical trial
• allergy or intolerance to more than one of wheat, barley, corn, oats, potato, legumes, nuts, psyllium, olives, avocado or canola
• unwilling or unable to follow the protocol and/or give informed consent
• subjects planning to be on holiday for more than 8 weeks in a row or a total of 12 weeks in the year in locations to which they will not take study food