Metabolic and Inflammatory Outcomes of the Ketogenic Diet Comparing Saturated and Unsaturated Fat Sources

The ketogenic diet (KETO) is popular for weight loss and is gaining interest as a treatment for type 2 diabetes (T2D) because it is believed to help manage blood glucose and weight. However, KETO is often high in saturated fats (SFA), which may increase cholesterol and other cardiovascular (CVD) risk factors, such as inflammatory profile. Substituting a heart-healthy oil for SFA may improve these outcomes. The purpose of our study is to investigate the health beneficial effects of a healthy KETO diet supplemented with Canola oil, compared to a traditional Keto Diet and low-fat diet in adults at high risk of type 2 diabetes. Participants will be randomized to one of these three diets and will receive nutrition counselling during 6 months. Each month, participants will receive a 1-month supply of canola oil in the KETO-Can group, butter and coconut oil in the KETO-Sat group and whole grain foods (pasta or brown rice) and oatmeal in the LFD group to ensure compliance to key nutrients. Fasting blood samples will be taken at baseline, 3 and 6 months. Anthropometric measurements (weight (BW), waist circumference (WC), BMI), blood pressure (BP), systemic inflammation (CRP, IL-6, TNF-α, IL-18), immune function, cardiometabolic risk factors (TG, cholesterol, glucose, insulin and HbA1C) will be determined at each time point. A total of three 24h-recall questionnaires (2 weekdays and 1 weekend day) will be completed at each time point (baseline, 3 months, 6 months). Once a month (in between study visits) a 24h-recall will be completed before meeting the nutrition expert in order to personalize recommendations according to participants' respective diet groups. As in any nutritional study, adherence for nutrition study is a key factor and will be measured differently during the intervention. Menu examples will be provided for each group to facilitate adherence. Adherence to the study protocol will be assessed by (1) evaluation of 24-h recall data (14 in total). Participants with 11 out of 14 recalls being within meeting dietary objectives will be considered highly compliant, 6 or less would be low compliance; (2) Ketosis state will be measured at each study visit using ketone strips to assess adherence to both KETO diets; (3) Participants will be asked to report the food consumed each month to determine the level of consumption. Finally, fatty acid composition in plasma (short-term) and red blood cells (RBCs; reflect the past 3 months) will be assessed to confirm adherence between the two keto diets.