Effects of glycemic index and amount of carbohydrate eaten at breakfast on the metabolic response to lunc

The overall purpose of this thesis was to test the hypothesis that breakfast meals leading to an higher plasma FFA levels at the start of lunch will produce an increased glycemic response to lunch.;To test this, the effect of the carbohydrate level and glycemic index (GI) of breakfast on the metabolic response to a standard lunch was studied using a randomized Latin square design. An 80g carbohydrate (CHO) breakfast yielded higher plasma glucose and insulin and lower triglyceride responses than isocaloric breakfasts containing 40g CHO. Low GI did not affect triglycerides but reduced the glycemic response to the high CHO breakfast. An interaction between the effect of CHO and GI on plasma FFA at 4 hours was observed. The high-CHO, low-GI breakfast produced the lowest FFA response, then the high-CHO, high-GI, followed by the low-CHO, high-GI. However, the low-CHO, low-GI produced the highest FFA at 4 hours. Blood glucose and insulin responses to the standard lunch differed and were related to the plasma FFA concentration at 4 hours.;It is concluded, varying the glycemic index and carbohydrate content of breakfast test meals significantly influenced plasma FFA responses. The glycemic response to a standard lunch was inversely related to the FFA response to breakfast.