Fetal hyperglycemia occurs when the developing fetus is exposed to high levels of glucose. For example in humans, this is the case when the mother has diabetes. Fetal hyperglycemia is linked to health complications for the fetus, including preeclamsia, fetal macrosomia and even fetal death. In addition, fetal hyperglycemia also increases the risk for the individual to develop a variety of diseases later in life. Adults exposed to fetal hyperglycemia are more susceptible to obesity, insulin resistance, type 2 diabetes, cardiovascular diseases and several metabolic syndromes. To date, the physiological and molecular mechanisms that underlie the link between fetal hyperglycemia and the adult sequelae are poorly understood. The central goal of this project is to examine the physiological and molecular basis of metabolic diseases in adults exposed to high levels of glucose only during embryogenesis. To accomplish this goal, we have recently developed a zebrafish model of fetal hyperglycemia. Zebrafish offers several advantages to complete this project. From a biological point of view, zebrafish embryos have the unique feature of being a “closed system” i.e for the first 5 days of development, the embryo solely relies on the yolk sac reserved deposited by the mother during ovulation and no energy exchange happens with the exterior world prior the end of embryogenesis. Therefore, in zebrafish we can directly expose the embryos to known concentration of glucose. Thus, specific aim 1 will test the hypothesis that fetal hyperglycemia leads to an increase in BMI, fat mass and insulin resistance in adults fed normal diet. Specific aim 2 will test the hypothesis that embryonic hyperglycemia increases glycolysis while decreasing β-oxidation in embryos and in adults. Specific aim 3 will test the hypothesis that fetal hyperglycemia causes hyperlipidemia and non-alcoholic fatty liver disease in adults. Specific aim 4 will test the hypothesis that embryonic hyperglycemia increases the levels of circulating lipids and causes atherosclerosis later in life. Successful completion of this proposal will lead to a better understanding of the physiological and molecular consequences of fetal hyperglycemia and will help in defining strategic therapeutic interventions to prevent the development of metabolic diseases in adults exposed to glucose during embryogenesis.