Response of Liver Metabolic Pathways to Ketogenic Diet and Exercise Are Not Additive

The Liver Circadian Metabolic Homeostasis Influence by Combining Ketogenic Diet with Exercise

The ketogenic diet (KD) and regular exercise (EX) are both capable of orchestrating circadian metabolism homeostasis during losing weight. However, the combined effects of these two factors on circadian metabolism remain poorly understood. To determine if the combined treatment yields a superimposed physiological phenotype, we measured weight loss, white adipose, the respiratory exchange ratio (RER), heat production, and activity parameters in individual and combined treatment groups. Surprisingly, none of these metrics displayed a cumulative effect when administered in the combined treatment approach. Additionally, we investigated the impact of combination therapy on molecular homeostasis through using high-throughput liver transcriptomic approaches. The results revealed that individual and combined treatments can reprogram the circadian rhythm; yet, the combined group exhibited a minimum quantity of cyclic transcript genes. Noteworthy, the amplitude of 24 h circadian expression genes was not significantly increased in the combination treatment, indicating that the combined approach has non-overlapping effects on maintenance peripheral metabolism homeostasis. This may be due to the liver requiring less ketogenic and gluconeogenic potential during metabolic processes. This research suggests that combined treatment may have adverse effects on the body's homeostasis and provide crucial insights for the homeostatic health of athletes or individuals who wish to lose weight.

Ketogenic diet influence on the elemental homeostasis of internal organs is gender dependent

The ketogenic diet (KD) is a low-carbohydrate and high-fat diet that gains increasing popularity in the treatment of numerous diseases, including epilepsy, brain cancers, type 2 diabetes and various metabolic syndromes. Although KD is effective in the treatment of mentioned medical conditions, it is unfortunately not without side effects. The most frequently occurring undesired outcomes of this diet are nutrient deficiencies, the formation of kidney stones, loss of bone mineral density, increased LDL (low-density lipoprotein) cholesterol levels and hormonal disturbances. Both the diet itself and the mentioned adverse effects can influence the elemental composition and homeostasis of internal organs. Therefore, the objective of this study was to determine the elemental abnormalities that appear in the liver, kidney, and spleen of rats subjected to long-term KD treatment. The investigation was conducted separately on males and females to determine if observed changes in the elemental composition of organs are gender-dependent. To measure the concentration of P, S, K, Ca, Fe, Cu, Zn and Se in the tissues the method of the total reflection X-ray fluorescence (TXRF) was utilized. The obtained results revealed numerous elemental abnormalities in the organs of animals fed a high-fat diet. Only some of them can be explained by the differences in the composition and intake of the ketogenic and standard diets. Furthermore, in many cases, the observed anomalies differed between male and female rats.

Normal diet ameliorates obesity more safely and effectively than ketogenic diet does in high-fat diet-induced obesity mouse based on gut microbiota and lipid metabolism

Growing evidence supports the efficacy of ketogenic diets for inducing weight loss, but there are also potential health risks due to their unbalanced nutrient composition. We aim at assessing relative effectiveness of a balanced diet and ketogenic diet for reversing metabolic syndrome in a diet-induced C57BL/6J mouse model. Mice were fed high-fat diet to induce obesity. Obese individuals were then fed either ketogenic or balanced diets as an obesity intervention. Serum, liver, fat and faecal samples were analysed. We observed that both diet interventions led to significant decrease in body weight. The ketogenic intervention was less effective in reducing adipocyte cell size and led to dyslipidaemia. The composition of the gut microbiome in the balanced diet intervention was more similar to the non-obese control group and had improved functional attributes. Our results indicate intervention with balanced diets ameliorates obesity more safely and effectively than ketogenic diets in diet-induced obesity mouse model.

Pharmacological inhibition of lipolysis prevents adverse metabolic outcomes during glucocorticoid administration

OBJECTIVE

Glucocorticoids are one of the most commonly prescribed classes of anti-inflammatory drugs; however, chronic treatment promotes iatrogenic (drug-induced) diabetes. As part of their physiological role, glucocorticoids stimulate lipolysis to spare glucose. We hypothesized that persistent stimulation of lipolysis during glucocorticoid therapy plays a causative role in the development of iatrogenic diabetes.

METHODS

Male C57BL/6J mice were given 100 μg/mL corticosterone (Cort) in the drinking water for two weeks and were fed either normal chow (TekLad 8640) or the same diet supplemented with an adipose triglyceride lipase inhibitor (Atglistatin - 2  g/kg diet) to inhibit the first step of lipolysis.

RESULTS

Herein, we report for the first time that glucocorticoid administration promotes a unique state of substrate excess and energetic overload in skeletal muscle that primarily results from the rampant mobilization of endogenous fuels. Inhibiting lipolysis protected mice from Cort-induced gains in fat mass, excess ectopic lipid accrual, hyperinsulinemia, and hyperglycemia. The role lipolysis plays in Cort-mediated pathology appears to differ between tissues. Within skeletal muscle, Cort-induced lipolysis facilitated diversion of glucose-derived carbons toward the pentose phosphate and hexosamine biosynthesis pathways but contributed to <3% of the Cort-induced genomic adaptations. In contrast, Cort stimulation of lipolysis accounted for ∼35% of the genomic changes in the liver but had minimal impact on hepatic metabolites reported.

CONCLUSIONS

These data support the idea that activation of lipolysis plays a causal role in the progression toward iatrogenic diabetes during glucocorticoid therapy with differential impact on skeletal muscle and liver.

Combined effects of a ketogenic diet and exercise training alter mitochondrial and peroxisomal substrate oxidative capacity in skeletal muscle

Ketogenic diets (KDs) are reported to improve body weight, fat mass, and exercise performance in humans. Unfortunately, most rodent studies have used a low-protein KD, which does not recapitulate diets used by humans. Since skeletal muscle plays a critical role in responding to macronutrient perturbations induced by diet and exercise, the purpose of this study was to test if a normal-protein KD (NPKD) impacts shifts in skeletal muscle substrate oxidative capacity in response to exercise training (ExTr). A high fat, carbohydrate-deficient NPKD (16.1% protein, 83.9% fat, 0% carbohydrate) was given to C57BL/6J male mice for 6 wk, whereas controls (Con) received a low-fat diet with similar protein (15.9% protein, 11.9% fat, 72.2% carbohydrate). After 3 wk on the diet, mice began treadmill training 5 days/wk, 60 min/day for 3 wks. The NPKD increased body weight and fat mass, whereas ExTr negated a continued rise in adiposity. ExTr increased intramuscular glycogen, whereas the NPKD increased intramuscular triglycerides. Neither the NPKD nor ExTr alone altered mitochondrial content; however, in combination, the NPKD-ExTr group showed increases in PGC-1α and markers of mitochondrial fission/fusion. Pyruvate oxidative capacity was unchanged by either intervention, whereas ExTr increased leucine oxidation in NPKD-fed mice. Lipid metabolism pathways had the most notable changes as the NPKD and ExTr interventions both enhanced mitochondrial and peroxisomal lipid oxidation and many adaptations were additive or synergistic. Overall, these results suggest that a combination of a NPKD and ExTr induces additive and/or synergistic adaptations in skeletal muscle oxidative capacity.NEW & NOTEWORTHY A ketogenic diet with normal protein content (NPKD) increases body weight and fat mass, increases intramuscular triglyceride storage, and upregulates pathways related to protein metabolism. In combination with exercise training, a NPKD induces additive and/or synergistic activation of AMPK, PGC-1α, mitochondrial fission/fusion genes, mitochondrial fatty acid oxidation, and peroxisomal adaptations in skeletal muscle. Collectively, results from this study provide mechanistic insight into adaptations in skeletal muscle relevant to keto-adaptation.

A Low-Carbohydrate Ketogenic Diet and Treadmill Training Enhanced Fatty Acid Oxidation Capacity but Did Not Enhance Maximal Exercise Capacity in Mice

The low-carbohydrate ketogenic diet (LCKD) is a dietary approach characterized by the intake of high amounts of fat, a balanced amount of protein, and low carbohydrates, which is insufficient for metabolic demands. Previous studies have shown that an LCKD alone may contribute to fatty acid oxidation capacity, along with endurance. In the present study, we combined a 10-week LCKD with an 8-week forced treadmill running program to determine whether training in conjunction with LCKD enhanced fatty acid oxidation capacity, as well as whether the maximal exercise capacity would be affected by an LCKD or training in a mice model. We found that the lipid pool and fatty acid oxidation capacity were both enhanced following the 10-week LCKD. Further, key fatty acid oxidation related genes were upregulated. In contrast, the 8-week training regimen had no effect on fatty acid and ketone body oxidation. Key genes involved in carbohydrate utilization were downregulated in the LCKD groups. However, the improved fatty acid oxidation capacity did not translate into an enhanced maximal exercise capacity. In summary, while favoring the fatty acid oxidation system, an LCKD, alone or combined with training, had no beneficial effects in our intensive exercise-evaluation model. Therefore, an LCKD may be promising to improve endurance in low- to moderate-intensity exercise, and may not be an optimal choice for those partaking in high-intensity exercise.