Figure 1.

The protocol followed a randomized crossover design with two 5-night in-laboratory sessions spaced by at least 1 month. Each session included one habituation night, followed by 4 experimental nights with either 4.5 (RS1-RS4, red bars) or 8.5 (NS1-NS4, black bars) h/night in bed. Over the third experimental night beginning at 21:00, 24-h blood sampling was initiated to examine circulating endocannabinoid, cortisol, leptin, and ghrelin levels (dashed lines). Throughout the following day, identical carbohydrate-rich meals were served at 09:00, 14:00, and 19:00 (denoted by black arrows). Questionnaires to assess hunger, appetite, vigor, and affect were administered at 08:35, 10:35, 13:35, 15:35, 18:35, and 20:35 (denoted by v). In the afternoon following the fourth experimental night, participants were exposed to an ad libitum (ad lib) buffet for lunch at 15:00 and dinner at 19:30 (denoted by open arrows), with a snack period between the meal opportunities (graded line).