Stepwise reintroduction of carbohydrate during refeeding after prolonged fasting.

In an attempt to minimize fluid retention and obtain a gradual return to the pre-fast metabolic state, 14 nondiabetic obese subjects, who had fasted totally for 32 +/- 3 days, were fed a hypocaloric diet that incorporated stepwise increments in carbohydrate beginning at 20 g/day. During the refeeding period of 14 days, the total caloric intake for the first 9 days was 800 kcal/day and 1000 kcal/day thereafter. No untoward clinical events occurred. A weight regain of 2.2 +/- 0.4 kg during the first 7 days was accounted for by fluid retention. The return to pre-fast postabsorptive plasma glucose levels (82 +/- 3 to 93 +/- 3 mg dl-1) and a rise in immunoreactive insulin (0.5 +/- 0.1 to 0.8 +/- 0.1 ng ml-1) occurred by day 7. Blood 3-hydroxybutyrate and acetoacetate concentrations (4.1 and 0.6 mM, respectively) declined more slowly to reach pre-fast values by day 14; urinary excretion of 3-hydroxybutyrate dropped from 64 mmol/day to pre-fast levels by day 10. Urinary nitrogen excretion increased from 2.6 to a plateau of 5.5-6.0 g/day from day 3 onward; nitrogen balance was at least +3 g/day throughout refeeding. This approach to refeeding is associated with acceptable clinical response and may be appropriate after other states of marked caloric deprivation.