a, b, General locomotor activity and feeding behaviour were monitored using infrared sensors and programmable feeders, respectively. Representative actograms obtained from an Opn4DTA mouse under free-running (constant darkness and ad libitum access to food) are shown (a). Periodograms were obtained, and no differences in period lengths were found between locomotor activity and the feeding behaviour for both groups (b). Data are mean ± s.e.m. (n = 12 mice for each genotype), two-way ANOVA, followed by Sidak’s multiple comparisons test. c, d, Representative actograms obtained from control (c) and Opn4DTA (d) mice exposed to TRF are shown. e, Under constant darkness and ad libitum acess to food, Opn4DTA mice displayed different free-running periods. Therefore, we analysed whether there is any correlation between the food-anticipatory activity (measured during a 3-h time window) and the time difference (measured in minutes) between the onset of locomotor activity and the time of food delivery measured during the first day of food restriction. No significant correlations (Pearson correlation test, P = 0.6379) were observed in Opn4DTA mice (n = 13 mice). f, The daily total amount of food consumed was measured in male (M) and female (F) control and Opn4DTA mice exposed to the free-running (ad libitum access to food) or TRF paradigm. Data are mean ± s.e.m. (n = 8 mice for each genotype), two-way ANOVA, followed by Sidak’s multiple comparisons test. g, Total food consumption per day during TRF. Data are mean ± s.e.m. (n = 8 mice for each genotype), multiple Student’s t-test, two tailed. h, Pattern of food consumption during the 7 h of food access. Data are mean ± s.e.m. (n = 8 mice for each genotype); multiple Student’s t-test, two tailed. i, Measurement of the body weight of female and male mice exposed to the TRF paradigm. Data are mean ± s.e.m. (n = 12 mice for each genotype), two-way ANOVA, followed by Sidak’s multiple comparisons test. j, The body composition was measured in mice with ad libitum access to food (AL), or on the 21st day of TRF. Data are mean ± SEM (n = 8 mice for each genotype), two-way ANOVA, followed by Sidak’s multiple comparisons test. k, Total ghrelin levels (ng ml−1) were measured in control and Opn4DTA mice after 7, 14, and 21 days of TRF. In all cases, samples were collected immediately before food delivery. Data are mean ± SEM (n = 8 mice for each genotype), Student’s t-test, two tailed.