Ketogenic Diet Combined with Moderate Aerobic Exercise Training Ameliorates White Adipose Tissue Mass, Serum Biomarkers, and Hepatic Lipid Metabolism in High-Fat Diet-Induced Obese Mice

Abstract

Obesity is a serious public health issue worldwide. Growing evidence demonstrates the efficacy of the ketogenic diet (KD) for weight loss, but there may be some adverse side effects such as dyslipidemia and hepatic steatosis. Aerobic exercise is a widely recognized approach for improving these metabolic markers. Here we explored the combined impacts of KD and moderate aerobic exercise for an 8-week intervention on body weight and fat loss, serum biomarkers, and hepatic lipid metabolism in a mouse model of high-fat diet-induced obesity. Both KD and KD combined with exercise significantly reduced body weight and fat mass. No significant adverse effects of KD were observed in serum biomarkers or hepatic lipid storage, except for an increase in circulating triglyceride level. However, aerobic exercise lowered serum triglyceride levels, and further ameliorated serum parameters, and hepatic steatosis in KD-fed mice. Moreover, gene and protein expression analysis indicated that KD combined with exercise was associated with increased expression of lipolysis-related genes and protein levels, and reduced expression of lipogenic genes relative to KD without exercise. Overall, our findings for mice indicate that further work on humans might reveal that KD combined with moderate aerobic exercise could be a promising therapeutic strategy for obesity.

Keywords: aerobic exercise; ketogenic diet; lipid metabolism; obesity.

Figure 1

Body weight change and energy intake over the 11-week dietary and aerobic exercise intervention in C57BL/6J obese mice. (A) Body weight change of HFD, HFD + EX, KD, KD + EX groups of mice. (B) Final body weight of HFD, HFD + EX, KD, and KD + EX groups of mice. (C) Average energy intake of each group. (D) Average food intake of each group. Values are given as mean ± SEM, n = 8. For panels (B–D), p values from the two-way ANOVA (i.e., main diet and exercise effects and diet*exercise interactions) are presented in the top left corner; Bonferroni post hoc test indicated significant differences (identified with an asterisk) at the following p values, ** p < 0.01; **** p < 0.0001; unpaired two-tailed Student’s t-test was used to indicate statistical significance between the KD and CON groups at the following p values, ### p < 0.001, #### p < 0.0001.

Figure 2

Energy metabolism in HFD, HFD + EX, KD, KD + EX groups of mice. (A) and (B) O₂ consumption (VO₂). (C) and (D) CO₂ production (VCO₂). (E) Respiratory exchange ratio (VCO₂/VO₂). (F) Energy expenditure. (G) Physical activity. Values are given as mean ± SEM, n = 3–4. For panels B, D, E and F, p values from the two-way ANOVA (i.e., main diet and exercise effects and diet*exercise interactions) are presented in the top left corner; Bonferroni post hoc test indicated significant differences (identified with an asterisk) at the following p values, * p < 0.05; *** p < 0.001; **** p < 0.0001.

Figure 3

Visceral fat masses and eWAT Diameters in four treatment groups of mice. (A) Visceral fat masses (n = 8). (B) Ratio of visceral fat to body weight (%) (n = 8). (C) Average diameter of eWAT cells (n = 5). (D) Representative HE staining of eWAT sections (Scale bars = 100 μm; Original magnification, 200×) (n = 5). (E) eWAT diameter range (n = 5). Data are presented as mean ± SEM. For panels A, B and C, p values from the two-way ANOVA (i.e., main diet and exercise effects and diet*exercise interactions) are presented in the top left corner; Bonferroni post hoc test indicated significant differences (identified with an asterisk) at the following p values, **** p < 0.0001. For panel E, # indicates the KD group is statistically different from the HFD group at the following p values, # p < 0.05, ### p < 0.001, #### p < 0.0001; $ indicates the HFD + EX group is statistically different from the HFD group at the following p values, $$ p < 0.01, $$$$ p < 0.0001.

Figure 4

Effects of KD intervention and KD combined with exercise on serum lipid metabolism and liver injury in each group. (A) TG, (B) TC, (C) LDL, (D) HDL, (E) AST and (F) ALT in serum. Data are presented as mean ± SEM, n = 6–8. For panels A–F, p values from the two-way ANOVA (i.e., main diet and exercise effects and diet*exercise interactions) are presented in the top left corner; Bonferroni post hoc test indicated significant differences (identified with an asterisk) at the following p values, **** p < 0.0001.

Figure 5

Effects of KD intervention and KD combined with exercise on hepatic lipid accumulation and hepatic steatosis. (A) Liver weight (n = 8). (B) Quantification of liver TG; (C) Representative images of HE staining of liver sections (Scale bars = 100 μm; Original magnification, 200×); (D) Representative images of Oil-red O staining of liver sections (Scale bars = 100 μm; Original magnification, 200×) (n = 5–6). Data are presented as mean ± SEM. For panels A and B, p values from the two-way ANOVA (i.e., main diet and exercise effects and diet*exercise interactions) are presented in the top left corner; Bonferroni post hoc test indicated significant differences (identified with an asterisk) at the following p values, * p < 0.05; ** p < 0.01.

Figure 6

Effects of KD intervention and KD combined with exercise on the fatty acid oxidation and synthesis-related gene expression in livers. Gene expression of (A) Pparα, (B) Fgf21 and (C) Pgc-1α, related to fatty acid oxidation in each group of mouse livers. Gene expression of (D) Acc1, (E) Acc2 and (F) Fasn, related to fatty acid synthesis in four group mouse livers. Data are presented as mean ± SEM, n = 6. For panels (A–F), p values from the two-way ANOVA (i.e., main diet and exercise effects and diet*exercise interactions) are presented in the top left corner; Bonferroni post hoc test indicated significant differences (identified with an asterisk) at the following p values, * p < 0.05; ** p < 0.01.

Figure 7

Effects of KD intervention and KD combined with exercise on the fatty acid oxidation and synthesis-related protein expression in each group of mouse livers. (A) Representative western blots. Protein quantification analysis of (B) FGF21, (C) CPT1A, (D) PGC-1α and (E) SCD1 in livers. Data are presented as mean ± SEM, n = 6. For panels B–E, p values from the two-way ANOVA (i.e., main diet and exercise effects and diet*exercise interactions) are presented in the top left corner.