abstract: The Western Pattern diet has been characterized by having greater than 50 percent consumption coming from fat and sugar. This macronutrient allocation has been shown to have deleterious effects on endothelial function and metabolic markers of cardiovascular disease. Exercise has been shown to improve vascular reactivity and metabolic markers related to cardiovascular health. The objective of the study was to determine if exercise training can prevent the anticipated deleterious effects of a fat-sugar supplemented diet on endothelial function and blood markers of cardiovascular risk in young men. Twenty-one, healthy college-aged males were randomly assigned to either the doughnut + exercise or doughnut only groups. Both groups were fed 2 doughnuts per day, 6 days per week, for three weeks, while maintain their current diet. The exercise group completed 4 exercise training sessions per week consisting of 2 high intensity interval training bouts (up to 95% VO2peak) on a cycle ergometer and two moderate intensity, steady-state bouts (at 75% VO2peak) on a treadmill. Changes in body weight and composition, markers of endothelial function, oxidative stress, serum lipids, and blood glucose were measured in each group. As expected, cardiovascular fitness increased significantly in the doughnut-supplemented + exercise group as compared to the doughnut-supplemented (p=0.005). Significant increases in body weight (p=0.036), fat mass (p=0.013), and body fat percentage (p=0.014) were seen in the doughnut only group as compared to the doughnut + exercise group. The doughnut + exercise group showed significant improvements in fasting serum triglycerides (p=0.036), plasma insulin (p=0.039) and insulin sensitivity (HOMA; p=0.05) as compared to the doughnut only group. The doughnut + exercise group saw a significant improvement in nitric oxide availability whereas the doughnut only group experienced a significant decline (p=0.014). There were no significant changes in other markers. Despite the addition of a fat/sugar supplement of ~11,600 kcal over three weeks, 4 exercise sessions per week were sufficient to prevent a gain in body weight and fat mass, and also improve some measures of cardiometabolic risk. These results suggest that exercise may be necessary to prevent some adverse health outcomes associated with transient periods of excessive energy consumption. / Dissertation/Thesis / Ph.D. Physical Activity, Nutrition and Wellness 2013

abstract: The winter holiday period has been highlighted as a major risk period for weight gain due to excess caloric intake in the form of fat and sugar. Furthermore, diets high in fat and sugar have been implicated in the pathogenesis of diabetes and cardiovascular disease. Exercise aids in the prevention of weight/fat gain, and prevents deleterious changes in cardiometabolic function. The objective of this study was to examine the effects of a fat-sugar supplemented diet, with and without two different exercise training protocols, on body composition, glycemic control and other markers of cardiovascular disease in an at-risk population of overweight and obese males. Twenty-seven, healthy overweight/obese (BMI >25 kg/m2) males were fed 2 donuts per day, 6 days/week, for four weeks, while maintaining their current diet. In addition, all subjects were randomized to one of the following conditions: sedentary control, 1,000 kcal/week moderate-intensity continuous training (MICT) (50% of peak oxygen consumption), or 1,000 kcal/week high-intensity interval training (HIIT) (90-95% of peak heart rate). Supervised exercise training was performed 4 days/week on a cycle ergometer. Changes in body weight and composition, endothelial function, arterial stiffness, glycemic control, blood lipids and cardiorespiratory fitness (CRF) were assessed before and after the intervention. Body weight, lean mass and visceral fat increased significantly in HIIT (p<0.05) and were unchanged in MICT. There was a trend for a significant increase in body weight (p=0.07) and lean mass (p=0.11) in control. Glycemic control during the 2-h OGTT improved significantly in MICT and control, with no change in HIIT. Hepatic insulin resistance index (IRI) and 30-min insulin during the OGTT improved significantly after MICT and worsened following control (p=0.03), while HIIT was unchanged. CRF increased significantly in both HIIT and MICT, with no change in control (p<0.001). There were no significant changes in other markers of cardiovascular disease. The addition of a fat-sugar supplement (~14,500 kcal) over a 4-week period was not sufficient to induce deleterious changes in body composition and cardiometabolic health in overweight/obese young males. Exercise training did not afford overweight/obese males additional health benefits, with the exception of improvements in fitness and hepatic IRI. / Dissertation/Thesis / Doctoral Dissertation Physical Activity, Nutrition and Wellness 2016