Calorie restriction on normal body weight mice prevents body weight regain on a follow-up high-fat diet by shaping an obesity-resistant-like gut microbiota profile

Intermittent fasting, exercise, and dietary modification induce unique transcriptomic signatures of multiple tissues governing metabolic homeostasis during weight loss and rebound weight gain

Obesity and its related metabolic diseases bring great challenges to public health. In-depth understanding on the efficacy of weight-loss interventions is critical for long-term weight control. Our study demonstrated the comparable efficacy of exercise (EX), intermittent fasting (IF), or the change of daily diet from an unhealthy to a normal chow (DR) for weight reduction, but largely divergently affected metabolic status and transcriptome of subcutaneous fat, scapular brown fat, skeletal muscles and liver in high-fat-high-fructose diet (HFHF) induced obese mice. EX and IF reduced systematic inflammation, improved glucose and lipid metabolism in liver and muscle, and amino acid metabolism and thermogenesis in adipose tissues. EX exhibited broad regulatory effects on TCA cycle, carbon metabolism, thermogenesis, propanoate-, fatty acid and amino acid metabolism across multiple tissues. IF prominently affected genes involved in mitophagy and autophagy in adipose tissues and core genes involved in butanoate metabolism in liver. DR, however, failed to improve metabolic homeostasis and biological dysfunctions in obese mice. Notably, by exploring potential inter-organ communication, we identified an obesity-resistant-like gene profile that were strongly correlated with HFHF induced metabolic derangements and could predict the degree of weight regain induced by the follow-up HFHF diet. Among them, 12 genes (e.g., Gdf15, Tfrc, Cdv3, Map2k4, and Nqo1) were causally associated with human metabolic traits, i.e., BMI, body fat mass, HbA1C, fasting glucose, and cholesterol. Our findings provide critical groundwork for improved understanding of the impacts of weight-loss interventions on host metabolism. The identified genes predicting weight regain may be considered regulatory targets for improving long-term weight control.

Supplementation of papaya leaf juice has beneficial effects on glucose homeostasis in high fat/high sugar-induced obese and prediabetic adult mice

Prediabetes is characterized by a cluster of glycemic parameters higher than normal but below the threshold of type 2 diabetes mellitus (T2DM). In recent years, phytochemical-rich plant extracts have gained popularity as therapeutic agents for metabolic disorders. This study investigated the effects of papaya leaf (PL) juice supplementation on blood glucose levels in diet-induced obese and prediabetic adult mice. B65JL F1 mice (n = 20) at 12-14 months old were fed a high fat/sugar diet (HFHS) for 120 days. Mice were switched to restricted rodent chow of 3 g feed/30 g body weight/day, supplemented with 3 g/100 mL PL juice for 30 days. HFHS diet remarkably increased fasting plasma glucose levels from 114 ± 6.54 mg/dL to 192.7 ± 10.1 mg/dL and body weight from 32.5 ± 1.6 to 50.3 ± 4.1 g. HFHS diet results in hyperglycemia, insulin resistance, hyperlipidemia, and liver steatosis. The combination of PL juice and restricted diet significantly reduced body weight and fasting blood glucose levels to 43.75 ± 1.4 g and 126.25 ± 3.2 mg/dl, respectively. Moreover, PL juice with a restricted diet significantly improved lipid profile: cholesterol from 204 to 150 mg/dL, LDL-c from 110.4 to 50 mg/dL, and triglyceride from 93.7 to 60 mg/dL. Additionally, PL juice combined with a restricted diet significantly reduced adiposity, reversed fatty liver, and restored skeletal muscle Glut4 and phosphorylated (p-AKT (ser473). This study demonstrated that supplementation of PL juice with a restricted diet was more effective than a restricted diet alone in reversing major symptoms related to prediabetic and obesity conditions.

A nexus of dietary restriction and gut microbiota: Recent insights into metabolic health

In recent times, dietary restriction (DR) has received considerable attention for its promising effects on metabolism and longevity. Previous studies on DR have mainly focused on the health benefits produced by different restriction patterns, whereas comprehensive reviews of the role of gut microbiota during DR are limited. In this review, we discuss the effects of caloric restriction, fasting, protein restriction, and amino acid restriction from a microbiome perspective. Furthermore, the underlying mechanisms by which DR affects metabolic health by regulating intestinal homeostasis are summarized. Specifically, we reviewed the impacts of different DRs on specific gut microbiota. Additionally, we put forward the limitations of the current research and suggest the development of personalized microbes-directed DR for different populations and corresponding next-generation sequencing technologies for accurate microbiological analysis. DR effectively modulates the composition of the gut microbiota and microbial metabolites. In particular, DR markedly affects the rhythmic oscillation of microbes which may be related to the circadian clock system. Moreover, increasing evidence supports that DR profoundly improves metabolic syndrome, inflammatory bowel disease, and cognitive impairment. To summarize, DR may be an effective and executable dietary manipulation strategy for maintaining metabolic health, however, further investigation is needed to elucidate the underlying mechanisms.

Dietary approaches for normalizing dysbiosis induced by high-fat, obesogenic diets

PURPOSE OF REVIEW

Given the world-wide problem of obesity, this review considers what types of dietary changes can be utilized to minimize the adverse effects of an obesogenic diet on the intestinal microbiota.

RECENT FINDINGS

In rodents fed high-fat diets containing lard or Western blend fats to induce obesity, switching to high-fat diets formulated to contain higher amounts of fiber or fiber-containing foods, plant extracts, omega-3 fatty acids or whole grains has beneficial effects on body weight, metabolic alterations, and the intestinal microbiota. Several studies show that the intestinal microbiota has a role in mediating the beneficial health effects of these dietary factors. Many aspects of the microbiota observed in animals when healthful dietary components were added to the feed have also been observed in humans who follow healthful dietary patterns.

SUMMARY

The data shows that specific foods and macronutrients can normalize the obesity-associated microbiota and improve metabolic health. These findings support the design of dietary interventions that would allow individuals to focus on diet quality independently of weight loss to mitigate the adverse sequelae of obesity.

Impact of caloric restriction on the gut microbiota

Caloric restriction (CR) and related time-restricted diets have been popularized as means of preventing metabolic disease while improving general well-being. However, evidence as to their long-term efficacy, adverse effects, and mechanisms of activity remains incompletely understood. The gut microbiota is modulated by such dietary approaches, yet causal evidence to its possible downstream impacts on host metabolism remains elusive. Herein, we discuss the positive and adverse influences of restrictive dietary interventions on gut microbiota composition and function, and their collective impacts on host health and disease risk. We highlight known mechanisms of microbiota influences on the host, such as modulation of bioactive metabolites, while discussing challenges in achieving mechanistic dietary-microbiota insights, including interindividual variability in dietary responses as well as other methodological and conceptual challenges. In all, causally understanding the impact of CR approaches on the gut microbiota may enable to better decode their overall influences on human physiology and disease.

Weight cycling based on altered immune microenvironment as a result of metaflammation

As a result of the obesity epidemic, more people are concerned about losing weight; however, weight regain is common, leading to repeated weight loss and weight cycling. The health benefits of early weight loss are nullified by weight regain after weight cycling, which has much more severe metabolic consequences. Weight cycling alters body composition, resulting in faster fat recovery and slower muscle reconstruction. This evident fat accumulation, muscle loss, and ectopic fat deposition destroy the intestinal barrier, increase the permeability of the small intestinal epithelium, and cause the lipotoxicity of lipid metabolites and toxins to leak into extraintestinal tissues and circulation. It causes oxidative stress and hypoxia in local tissues and immune cell infiltration in various tissues, all contributing to the adaptation to this metabolic change. Immune cells transmit inflammatory responses in adipose and skeletal muscle tissue by secreting cytokines and adipokines, which mediate immune cell pathways and cause metaflammation and inefficient metabolic degradation. In this review, we focus on the regulatory function of the immunological microenvironment in the final metabolic outcome, with a particular emphasis on the cellular and molecular processes of local and systemic metaflammation induced by weight cycling-induced changes in body composition. Metaflammation in adipose and muscle tissues that is difficult to relieve may cause weight cycling. As this chronic low-grade inflammation spreads throughout the body, metabolic complications associated with weight cycling are triggered. Inhibiting the onset and progression of metabolic inflammation and enhancing the immune microenvironment of adipose and muscle tissues may be the first step in addressing weight cycling.