Ghrelin predicts food consumption up to three hours prior to eating: A randomised controlled trial

Eating triggers a cascade of metabolic, neural, and subjective signals that unfold and interact over several hours, typically suppressing the motivation to eat until the next meal. Which of these signals predict next-meal intake is not well understood. In a cross-over, double-blinded, and repeated measures factorial design over four separate test days, we manipulated both the protein and caloric content of four preload meals to experimentally induce differences in satiety. We investigated how the neural, subjective, hormonal, and metabolite states unfolded after a meal and how much each of them predicted the next meal intake 3 h later. Bayesian analysis revealed an extreme level of evidence for the inclusion of the peptide hormone ghrelin as a predictor of next meal energy intake. This predictive effect was consistently found for all time points, including also the time point immediately preceding preload consumption. When measured immediately before the ad libitum test meal, the plasma level of the gut hormone Glucagon-like Peptide-1 (GLP-1) and the subjective report of estimated consumption also predicted next-meal intake. No other measure, including the protein and caloric content of the preload, adequately predicted next-meal intake. Our results link ghrelin levels with the regulation of food intake several hours later.