PMC

Caloric intake and the source of calories were assessed over 3 weeks. (A) Rats with daily access to cafeteria diet consumed significantly more calories over the 3 weeks of feeding than the chow only group (n = 14-19/group). (B) The cafeteria diet group consumed significantly more calories from cafeteria diet food items than from chow pellets (n = 19). (C) The chow only group consumed more calories from chow pellets than the cafeteria diet group (n = 14-19/group). (D) Cafeteria diet access resulted in increased weight gain over the 3 weeks of feeding (n = 14-19/group). (E) Four weeks of cafeteria diet feeding significantly increased body weight, compared to chow only fed controls (main effect of diet, p < 0.001, two-way ANOVA, n = 44-46/group). (F) Throughout the 4 weeks of cafeteria diet access, the cafeteria diet group consumes significantly less chow than the chow only group (main effect of diet, p < 0.0001, two-way ANOVA, n = 10-11/group). * p < 0.05, ** p < 0.01, *** p < 0.001, Bonferroni post hoc test.

(A) Mean baseline sucrose drinking (mL/kg) over the 7 days prior to cafeteria diet feeding was similar between groups (p = 0.6489, Student’s t-test, n = 15-16/group). (B) Prior cafeteria diet feeding (4 weeks) transiently altered sucrose (5%, w/v, 2hr/day) consumption (diet x time interaction, p < 0.005, two-way ANOVA, n = 15-16/group). (C) There was no difference in water consumption between groups (n = 15-16/group). (D) Prior cafeteria diet feeding transiently reduced chow intake (n = 10/group). *** p < 0.001, Bonferroni post hoc test.

Schematic representation of the experimental feeding schedule. Male Wistar rats were allowed a 15-dayadaptationperiod prior to beginning the experiment and were divided into four groups as follows: NC–A (normal chow, ad libfeeding); NC–R (normal chow time, restricted feeding); CAF–A (cafeteria diet, ad libfeeding); and CAF–R (cafeteria diet, time-restricted feeding). Time-restricted feeding groups were allowed to feed for 8 h per day during the dark phase between ZT 13 and ZT 21. After sixteen weeks of experiment, animals were sacrificed. CAF: cafeteria diet; NC: normal chow diet; TRF: time-restricted feeding; ZT: Zeitgeber.

Effects of time-restricted feeding on thermogenic protein levels in the inguinal WAT of normal chow and cafeteria fed rats as measured by Western blot: (a) representative blot of UCP1 and PGC1α; (b,c) densitometry quantification of UCP1 and PGC1α protein levels. NC–A: normal chow ad libfeeding; NC–R: normal chow time-restricted feeding; CAF–A: cafeteria diet ad libfeeding; CAF–R: cafeteria time-restricted feeding; NC: normal chow diet; CAF: cafeteria diet.Values are means ± S.D (n = 3) of ratios of specific protein levels to β-actin (Loading protein). Data of the NC–A group wereset to 100% and the rest of the values are referred to this. ^# p < 0.05 CAF–A vs. NC–A rats; ** p < 0.01 NC–R vs. NC–A rats; ^×× p < 0.01 CAF–R vs. CAF–A rats (Mann–Whitney U-test).