The effects of short-term low-carbohydrate and ketogenic interventions on cardiometabolic health

Type 2 diabetes (T2D) is currently one of the most common chronic diseases worldwide and is characterized by impaired insulin secretion and action, elevated blood glucose and chronic inflammation. Lifestyle interventions including exercise and nutritional manipulations are considered first-line non-pharmacological treatments for this metabolic disease. While most health care providers agree that diet is of extreme importance for the prevention and management of T2D, the type of diet that should be consumed is highly debated. One dietary intervention, the low-carbohydrate high-fat (LCHF) diet, has been shown to be particularly effective at improving diabetes symptoms by reducing glucose excursions and lowering hyperinsulinemia. The first study of this thesis was to determine if changes in insulin levels in saliva were reflective of those observed in plasma following high and low-carbohydrate meals in 20 individuals (10 normal weight; BMI 20.0–24.9 kg/m2 and 10 with overweight/obesity; BMI > 28.0 kg/m2). The findings of this study indicate that saliva could potentially be used to delineate between low and high insulin levels following mixed meals, providing a potential avenue for personalizing dietary choices based on non-invasive saliva insulin measurement. In a second study, the effect of three 4-day diet interventions: i) Low-fat low-glycemic index (GL); ii) LCHF, and iii) LCHF with 15-min post-meal walks (LC+Ex) on the inflammatory and glycemic profiles of 11 individuals with T2D were compared. The main findings were that: a) LCHF and LCHF+EX improved glycemic control and proinsulin levels to a greater extent than GL and b) all diets improved some markers of inflammation. For the third and fourth study, we investigated the isolated effect of a new exogenous ketone monoester (KM) drink taken before a 2-hour oral glucose tolerance test in 20 healthy young individuals (BMI < 25 kg/m2) and 15 adults with overweight/obesity (BMI ≥ 28 kg/m2). The main findings are that the KM improved glucose control and decreased non-esterified fatty acids levels without a concomitant increase in circulating insulin. Overall, low-carbohydrate diets and ketone supplements seem to be effective at controlling glucose levels and could be considered as preventive and management therapies for metabolic diseases.Health and Social Development, Faculty of (Okanagan)Health and Exercise Sciences, School of (Okanagan)Graduat