Research paper
Natalucci G, Riedl S, Gleiss A, Zidek T, Frisch H. Spontaneous 24-h ghrelin secretion pattern in fasting subjects: maintenance of a meal-related pattern. European Journal of Endocrinology. 2005;152(6):845-850. doi:10.1530/eje.1.01919
Why we cite it
A key complement to Cummings et al. 2001 (csh01): while Cummings showed ghrelin rises before meals in fed subjects, Natalucci et al. showed that the same meal-related ghrelin pattern persists during a complete 24-hour fast. In six healthy volunteers (3 female, mean age 25.5, BMI 22.8), blood sampled every 20 minutes across a 24-hour fast. That sample is the whole of it, and it is the evidence behind the project’s hunger comes in waves message: ghrelin rose at customary meal times and then fell spontaneously, without food. The overall decrease in ghrelin during fasting further supports the project’s messaging that hunger adapts and diminishes. The authors’ conclusion that cephalic (brain) control primarily regulates meal initiation — not just stomach signals — reinforces that hunger timing is learned and scheduled. Note: a gen-1 source claimed “hunger perception also decreased during the second half” of the fast, but the abstract reports only ghrelin measurements, not subjective hunger ratings; this claim may appear in the full text but is unverified from the abstract alone.