Increasing energy expenditure by activating thermogenesis in brown and beige adipocytes is a critical approach to protect against obesity. Here, we investigated the action and mechanism of a natural polymethoxyflavone on adaptive thermogenesis in high‐fat diet‐induced obesity mouse model. Nobiletin treatment significantly ameliorated obesity, alleviated the whitening of brown adipose tissue, and promoted browning of white adipose tissue in mice fed a high‐fat diet. Gut microbiota analysis and metabolomic profiling revealed that nobiletin treatment resulted in a composition shift in the gut microbiota thereby altering fermentation products acetate levels in the host feces and serum. Further, transplantation of the microbiota from nobiletin‐treated mice to microbiota‐depleted mice activated brown adipose tissue activity, promoted beige adipocytes formation, and improved high‐fat diet‐induced obesity. Our results indicate that nobiletin could be used as a dietary therapy to prevent HFD‐induced obesity, and provide a potential target‐specific gut microbial species‐driven mechanism for activating thermogenesis in brown and beige adipocytes.

Diet and nutrition comprise a complex, multi-faceted interface between animal biology and food environments. With accumulating information on the many facets of this association arises a need for systems-based approaches that integrate dietary components and their links with ecology, feeding, post-ingestive processes and the functional and ecological consequences of these interactions. We briefly show how a modelling approach, nutritional geometry, has used the experimental control afforded in laboratory studies to begin to unravel these links. Laboratory studies, however, have limited ability to establish whether and how the feeding and physiological mechanisms interface with realistic ecological environments. We next provide an overview of observational field studies of free-ranging primates that have examined this, producing largely correlative data suggesting that similar feeding mechanisms operate in the wild as in the laboratory. Significant challenges remain, however, in establishing causal links between feeding, resource variation and physiological processes in the wild. We end with a more detailed account of two studies of temperate primates that have capitalized on the discrete variation provided by seasonal environments to strengthen causal inference in field studies and link patterns of intake to dynamics of nutrient processing. This article is part of the theme issue ‘Food processing and nutritional assimilation in animals’.

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.

Evolving evidence supports the role of the ketogenic diet (KD) in weight loss. However, no coherent conclusions are drawn on its impact on the effect of KD on exercise and antioxidant capacity after weight loss in obese individuals. We evaluated the exercise performance, energy metabolism and antioxidant capacity of mice after weight loss using high-fat diet-induced obese mice, and used KD and normal diet (ND) intervention, respectively, to provide a theoretical basis for further study of the health effects of KD. Our results showed that the 8-week KD significantly reduced the body weight of obese mice and improved the performance of treadmill exercise, but had no significant effect on grip strength. Serum biochemical results suggest that KD has the risk of elevating blood lipid. In liver tissue, KD significantly reduced the level of oxidative stress and increased the antioxidant capacity of the liver. Our findings suggest that the intervention with KD led to weight loss, modulate energy metabolism and improve aerobic exercise endurance in obese mice. Despite its antioxidant potential in the liver, the utilization of KD still requires caution. This study underscores the need for further investigation into the health impacts of KD, especially in regard to its potential risks.

Background: Icariin (ICA) is a flavonoid, that has been shown to exert antioxidant and anti-inflammatory effects. We aimed to explore the effects of acute exhaustive exercise on skeletal muscle injury and inflammatory factor levels, and investigate the anti-injury and anti-inflammatory effects of ICA through gut microbiota modulation. Methods: Thirty C57BL/6J mice were administered ICA by gavage for 8 consecutive weeks, which were randomly divided into 3 groups as follows: solvent gavage control group (CON), 25 mg/kg ICA gavage group (ICA-L), and 50 mg/kg ICA gavage group (ICA-H). Serum biochemical and skeletal muscle antioxidant indicators were measured. Antioxidant enzyme activities and anti-inflammatory factor levels were determined. Additionally, gut microbiota were sequenced and analyzed by 16S rDNA and the correlations between metabolic indices and microbial species were assessed using Spearman correlation analysis. Results: ICA alleviated oxidative stress in skeletal muscle by reducing malondialdehyde (MDA) levels and upregulating the activities and mRNA expression of antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-PX)). In addition, ICA suppressed inflammation through downregulation of tumor necrosis factor (TNF-α), nuclear factor-κB (NF-κB), and inflammatory cytokines (interleukin-6 (IL-6) and interleukin-1β (IL-1β)). Gut microbiota analysis revealed ICA enriched short-chain fatty acid (SCFA)-producing bacteria while inhibiting pathogens, with microbial shifts significantly correlated with muscle injury and antioxidant parameters, including Lachnospiraceae_NK4A136_group, Mucispirillum, and Harryflintia. Conclusions: Our study demonstrated that ICA ameliorated exercise-induced acute muscle injury and inflammation in mice by modulating gut microbiota composition and regulating NF-κB signaling pathway along with related antioxidant enzyme gene expression.