In spite of numerous studies of short-term (less than 30 days) fasts, current knowledge of prolonged fasting, the mechanisms of adaptation, and the causes of death are limited.A healthy 48-year-old man fasted voluntarily, on water only, for 54 days, during which time he offered himself as an experimental subject. Numerous metabolic parameters were measured, and his mental state was evaluated.… Read More

Exhaustive graded exercise leads to changes of hormones, carbohydrate, and lipid metabolism in normal controls and obese patients after prolonged starvation. Concomitant with a large increase of plasma catecholamines, insulin concentration is reduced and blood glucose levels slowly increase. More glucose is made available by glycogenolysis and gluconeogenesis than can be oxidized in the… Read More

An increased mobilization of the hepatic glycogen is necessary for the maintenance of glucose homeostasis during exercise. To examine the effect of exercise on glucose metabolism when the hepatic glycogen stores are depleted, five prolonged-fasted (60-h, PF) subjects were investigated. Arterial concentrations and splanchnic exchange of glucose and gluconeogenic precursors were studied at rest… Read More

The plasma GIP response to an oral 50 g glucose tolerance test has been compared in eight non-obese human subjects after 12 and 36 h of fasting. Basal plasma GIP and basal plasma insulin concentrations were similar after 12 and 36 h of fasting. Basal blood glucose was lower after 36 h fasting than after 12 h fasting (p less than 0.0125). After 36 h fasting the oral glucose tolerance test… Read More

The concentration of ketone bodies and their rate of transport (estimated with an infusion of beta-[14C]-hydroxybutyrate) were determined before, during, and after exercise in overnight-fasted and 3- to 5-day-fasted subjects who walked on a treadmill for 2 h at approximately 50% of their VO2max. In overnight-fasted subjects, exercise increased the rate of turnover (+125% after 2 h) and the… Read More

We have previously reported that caloric deprivation inhibits peripheral T4 metabolism and blunts the TSH response to TRH in euthyroid obese subjects. To determine whether these phenomena also occur in hypothyroid subjects, T4, T3, rT3, and the TSH response to TRH were measured initially and after a 60-h fast in seven hypothyroid patients. Short term fasting caused a 29% decrement in the… Read More

Fasting is known to result in marked decreases in urinary urea nitrogen excretion over a 7-day period. In the present studies, changes in whole body protein breakdown rates and in the circulating levels of a number of hormones involved in protein anabolism and catabolism were systematically studied in nine obese subjects after 12 h and after 7 days of fasting. Whole body protein breakdown… Read More