Research paper
Cummings DE, Purnell JQ, Frayo RS, Schmidova K, Wisse BE, Weigle DS. A preprandial rise in plasma ghrelin levels suggests a role in meal initiation in humans. Diabetes. 2001;50(8):1714-1719. doi:10.2337/diabetes.50.8.1714
Why we cite it
The first study to demonstrate a clear preprandial ghrelin surge in humans on a fixed meal schedule, establishing ghrelin as a physiological meal-initiation signal rather than merely a fasting-response hormone. By sampling 38 times over 24 hours in 10 healthy subjects, Cummings et al. showed that ghrelin nearly doubles before each meal and crashes within an hour after eating — a pattern reciprocal to insulin. The discovery of the diurnal rhythm (nadir at 0900, zenith at 0100) is particularly important for the project: it explains the counterintuitive fact that morning hunger is low despite the overnight fast, and it grounds the project's messaging that hunger is scheduled, not simply a fuel gauge.
DOI: 10.2337/diabetes.50.8.1714 · PubMed 11473029 · Publisher