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Dissecting the role of timing and caloric intake in energy balance
Author(s) -
Lashinger Laura M,
McKenzie Meredith R,
Bray Molly S
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.311.1
Subject(s) - medicine , endocrinology , food intake , caloric theory , basal metabolic rate , energy balance , chemistry , caloric intake , restricted diet , zoology , body weight , biology , ecology
CR has been shown to extend longevity and blunt disease progression. One mechanism by which caloric restriction is hypothesized to exert its effects, in addition to simply restricting energy intake, is through entrainment of cellular circadian clocks. Neurohumoral factors released following food intake have been demonstrated to be among the strongest entrainers of molecular clocks, which have been shown to regulate multiple metabolic processes. The purpose of this study was to examine the independent effects of timing versus quantity of macronutrient intake. Methods We randomly assigned 48 6‐week‐old male FVB/N mice to low fat (10%kcal from fat; LF) or high fat (45% kcal from fat; HF) diets for 9 weeks. Mice were further randomized within diet to either ad libitum (AL) or 3 timed feeding groups: 2 hr (2H), 4 hr (4H), and 6 hr (6H) food access beginning at zt12 (lights off). Food intake and body weights were measured weekly. Body composition was assessed by MRI, and functional glucose metabolism was assessed by a glucose tolerance test (GTT) at week 9. Results Mice exposed to LF diet for 2H (63.7 ± 7.3 kcal) or 4H (73.0 ± 3.8 kcal) ate significantly fewer kcal/wk compared to the 6H (82.6 ± 4.0 kcal) and AL (86.6 ± 6.3 kcal) groups (p<0.001). Consistent with their eating patterns, mice exposed to LF diet for 2H (20.9 ± 2.9 g) or 4H (24.6 ± 1.1 g) had significantly lower body weight (p<0.05) than AL (28.1 ± 2.4 g), although percent body fat was not different between groups. Surprisingly, after controlling for body weight, animals in the 4H (922.0 ± 100.9 AUC) and 6H (913.5 ± 165.7 AUC) groups were significantly less glucose tolerant compared to the AL group (725.0 ± 75.81 AUC; p<0.02). For the HF diet groups, no significant differences were observed in kcal or gram intake; however, mice exposed to the HF diet for 2H (24.6 ± 1.41 g) or 4H (25.8 0.99 g) had significantly lower body weight compared to the 6H (26.6 ± 1.13 g) and AL (28.4 ± 1.48 g) groups. Glucose tolerance was significantly lower in the 4H (901.2 ± 84.4 AUC) and 6H (885.3 ± 63.7 AUC) groups eating HF diets, compared to AL (788.6 ± 67.3 AUC). Conclusion Despite equivalent or lower body weight compared to AL‐fed animals, eating in shorter bouts (4 or 6H) resulted in poorer glucose tolerance, regardless of total fat intake.