Figure 1. Clinical protocol and intervention characteristics.

(A) Schematic of the protocol, showing the intervals between the fixed caloric meals and temporal drawing of research blood. (B–D) Data points and means (horizontal bars) of subjects’ sera (B) insulin, (C) glucose, and (D) growth hormone levels at the end of the 24-hour fast and 1 and 3 hours following the fixed caloric meal (n = 19). The fasting insulin level was found to be less than 50% of the insulin level 3 hours after the 500 caloric meal in this young healthy cohort, supporting the integrity of the fast. (E and F) Percentage of subjects that displayed ketones in (E) sera (n = 13) or (F) urine (n = 18). Statistical testing for changes in metabolite and hormone levels were performed using randomized block design ANOVA.