Microbial phenolic metabolites 3-(3',4'-dihydroxyphenyl)propanoic acid and 3',4'-dihydroxyphenylacetic acid prevent obesity in mice fed high-fat diet

Obesity is associated with numerous metabolic disorders,and dietary polyphenols have been confirmed to have beneficial effects on the metabolism in obesity.However,the effect of 3-(3’,4’-dihydroxyphenyl)propanoic acid(DHPA)and 3’,4’-dihydroxyphenylacetic acid(DHAA),two main metabolites of dietary polyphenols,on obesity remains poorly understood.In this study,DHPA and DHAA were found to alleviate obesity,as well as regulate insulin resistance,lipid metabolism,and oxidative stress response in high-fat diet(HFD)mice.Surprisingly,the 16S rRNA sequencing and UHPLC-Q-TOF/MS demonstrated that DHPA and DHAA only slightly disturbed the intestinal microbiome,but significantly altered the urine metabolome of HFD mice mainly by regulating pentose and glucuronate interconversion,tyrosine metabolism,pentose phosphate and tricarboxylic acid(TCA)cycle as indicated by metabolic pathway analysis based on Kyoto Encyclopedia of Genes and Genomes(KEGG)database.Correlation analysis revealed that the differential metabolites are strongly associated with body weight,blood glucose,insulin level,and superoxide dismutase(SOD)enzyme activity.Our results revealed that DHPA and DHAA exert their anti-obesity effect by regulating important metabolites in the glucose,lipid and tyrosine metabolism pathways.

Gut-brain axis as a bridge in obesity and depression:Mechanistic exploration and therapeutic prospects

A recent study by Wang et al,published in the World Journal of Psychiatry,provided preventative and therapeutic strategies for the comorbidity of obesity and depression.The gut-brain axis,which acts as a two-way communication system between the gastrointestinal tract and the central nervous system,plays a pivotal role in the pathogenesis of these conditions.Evidence suggests that metabolic byproducts,such as short-chain fatty acids,lipopolysaccharide and bile acids,which are generated by the gut microbiota,along with neurotransmitters and inflammatory mediators within the gut-brain axis,modulate the host's metabolic processes,neuronal regulation,and immune responses through diverse mechanisms.The interaction between obesity and depression via the gut-brain axis involves disruptions in the gut microbiota balance,inflammatory immune responses,and alterations in the neuroendocrine system.Modulating the gut-brain axis,for example,through a ketogenic diet,the use of probiotics,and the supplementation of antioxidants,offers new remedial approaches for obesity and depression.Future research that explores the mechanisms of the gut-brain axis is needed to provide more evidence for clinical treatment.

Obesity paradox in patients with community-acquired pneumonia:Have you fully considered the confounding factors?

There exists a notion that there is an obesity paradox in the prognosis of community-acquired pneumonia.In other words,obese individuals with communityacquired pneumonia have a better prognosis.The study by Wang et al supports this claim,but we believe that the obesity paradox should not be proposed hastily as it is influenced by numerous subjective and objective confounding factors.

Effect of bariatric surgery on metabolism in diabetes and obesity comorbidity:Insight from recent research

Obesity is a prevalent cause of diabetes mellitus(DM)and is a serious danger to human health.Type 2 DM(T2DM)mostly occurs along with obesity.Foodborne obesity-induced DM is caused by an excessive long-term diet and surplus energy.Bariatric surgery can improve the symptoms of T2DM in some obese patients.But different types of bariatric surgery may have different effects.There are some models built by researchers to discuss the surgical procedures’effects on me-tabolism in diabetes animal models and diabetes patients.It is high time to conclude all this effects and recommend procedures that can better improve metabolism.

Selenoprotein P1 as a biomarker of insulin resistance in pediatric obesity:Insights and implications

This editorial discusses the findings of Elbarky et al on the role of selenoprotein P1(SEPP1)in pediatric obesity and insulin resistance.Their study uncovered si-gnificantly lower SEPP1 Levels in children who were obese compared with hea-lthy peers,demonstrating a negative correlation between SEPP1 levels and mea-sures of adiposity and insulin resistance.These findings suggest that SEPP1 is a biomarker useful in the early identification of insulin resistance in pediatric populations.This editorial emphasizes the clinical implications of the study and calls for further research to validate and explore the role of SEPP1 in metabolic health.

New advances of adiponectin in regulating obesity and related metabolic syndromes

Obesity and related metabolic syndromes have been recognized as important disease risks,in which the role of adipokines cannot be ignored.Adiponectin(ADP)is one of the key adipokines with various beneficial effects,including improving glucose and lipid metabolism,enhancing insulin sensitivity,reducing oxidative stress and inflammation,promoting ceramides degradation,and stimulating adipose tissue vascularity.Based on those,it can serve as a positive regulator in many metabolic syndromes,such as type 2 diabetes(T2D),cardiovascular diseases,non-alcoholic fatty liver disease(NAFLD),sarcopenia,neurodegenerative diseases,and certain cancers.Therefore,a promising therapeutic approach for treating various metabolic diseases may involve elevating ADP levels or activating ADP receptors.The modulation of ADP genes,multimerization,and secretion covers the main processes of ADP generation,providing a comprehensive orientation for the development of more appropriate therapeutic strategies.In order to have a deeper understanding of ADP,this paper will provide an all-encompassing review of ADP.

Insights into the interplay between gut microbiota and lipid metabolism in the obesity management of canines and felines

Obesity is a prevalent chronic disease that has significant negative impacts on humans and our companion animals,including dogs and cats.Obesity occurs with multiple comorbidities,such as diabetes,hypertension,heart disease and osteoarthritis in dogs and cats.A direct link between lipid metabolism dysregulation and obesity-associated diseases has been implicated.However,the understanding of such pathophysiology in companion animals is lim-ited.This review aims to address the role of lipid metabolism in various metabolic disorders associated with obesity,emphasizing the involvement of the gut microbiota.Furthermore,we also discuss the management of obesity,including approaches like nutritional interventions,thus providing novel insights into obesity prevention and treatment for canines and felines.

Polysaccharides of Aspergillus cristatus attenuate obesity by regulating gut microbiota and gut microbiota-related metabolites

Golden-flower fungus,the only dominant microorganism determining the Fu-brick tea quality through fermentation and the important microbe in Liupao tea,is considered a potential probiotic fungus based on its anti-obesity effect.However,the classification of golden-flower fungi is still controversial;the anti-obesity effect of golden-flower fungus polysaccharides remains unknown.In this study,we identify a golden-flower strain as Aspergillus cristatus based on morphological characteristics and multigene phylogeny analysis,which resolves the controversy of classification.Moreover,we find A.cristatus polysaccharides(ACPS)attenuate obesity in rats.ACPS modulate gut bacterial composition.in which Akkermansia,Akkermansia muciniphila,Bacteroides,Romboutsia,Blautia,and Desulfovibrio are considered the core microbes regulated by ACPS.ACPS increase fecal total short-chain fatty acid content and serum,hepatic,and fecal total bile acid content.Furthermore,ACPS-induced gut microbiota alteration plays a causal role in the protection from obesity,according to a fecal transplantation experiment.Thus,ACPS ameliorate obesity by regulating gut microbiota and gut microbiota-related metabolites.

Junshanyinzhen tea extract prevents obesity by regulating gut microbiota and metabolic endotoxemia in high-fat diet fed rats

Obesity is associated with gut dysbiosis and metabolic endotoxin.Junshanyinzhen tea extract(JSTE)reduced fat accumulation and body weight in obese mice.However,the effects and mechanism of JSTE in preventing obesity were unclear.Therefore,we used different doses of JSTE(75,150 and 300 mg/(kg·day))to evaluate the effect on high-fat diet(HFD)-induced rats under 8 weeks of intervention.Here,our results showed that JSTE could significantly reduce body weight gain,blood lipid levels and fat accumulation,improve fatty damage in liver tissue(P<0.05).In addition,JSTE increased the expression of intestinal tight junction proteins(P<0.05),relieved metabolic endotoxemia(P<0.05)and chronic low-grade inflammation in HFD rats.Sequencing of fecal samples showed that JSTE could effectively reverse the microbial diversity and the ratio of Firmicutes to Bacteroidetes to normal levels in HFD-fed rats.Desulfovibrioceae and Erysipelotrichaceae,which are positively related to obesity,were decreased by JSTE intervention(P<0.05).while Bifidobacteriaceae,Bacteroidaceae,Akkermansia,and Clostridium,which are negatively related to obesity,were increased.Together,these results suggested that JSTE might effectively prevent obesity by modulating gut microbiota dysbiosis,intestinal barrier dysfunction,metabolic endotoxemia and chronic low-grade infl ammation in HFD-induced rats.

Hepatic protein phosphatase 1 regulatory subunit 3G alleviates obesity and liver steatosis by regulating the gut microbiota and bile acid metabolism

Intestinal dysbiosis and disrupted bile acid(BA)homeostasis are associated with obesity,but the precise mechanisms remain insufficiently explored.Hepatic protein phosphatase 1 regulatory subunit 3G(PPP1R3G)plays a pivotal role in regulating glycolipid metabolism;nevertheless,its obesity-combatting potency remains unclear.In this study,a substantial reduction was observed in serum PPP1R3G levels in high-body mass index(BMI)and high-fat diet(HFD)-exposed mice,establishing a positive correlation between PPP1R3G and non-12a-hydroxylated(non-12-OH)BA content.Additionally,hepatocyte-specific overexpression of Ppp1r3g(PPP1R3G HOE)mitigated HFD-induced obesity as evidenced by reduced weight,fat mass,and an improved serum lipid profile;hepatic steatosis alleviation was confirmed by normalized liver enzymes and histology.PPP1R3G HOE considerably impacted systemic BA homeostasis,which notably increased the non-12-OH BAs ratio,particularly lithocholic acid(LCA).16S ribosomal DNA(16S rDNA)sequencing assay indicated that PPP1R3G HOE reversed HFD-induced gut dysbiosis by reducing the Firmicutes/Bacteroidetes ratio and Lactobacillus population,and elevating the relative abundance of Blautia,which exhibited a positive correlation with serum LCA levels.A fecal microbiome transplantation test confirmed that the anti-obesity effect of hepatic PPP1R3G was gut microbiotadependent.Mechanistically,PPP1R3G HOE markedly suppressed hepatic cholesterol 7a-hydroxylase(CYP7A1)and sterol-12a-hydroxylase(CYP8B1),and concurrently upregulated oxysterol 7-a hydroxylase and Takeda G protein-coupled BA receptor 5(TGR5)expression under HFD conditions.Furthermore,LCA administration significantly mitigated the HFD-induced obesity phenotype and elevated non-12-OH BA levels.These findings emphasize the significance of hepatic PPP1R3G in ameliorating diet-induced adiposity and hepatic steatosis through the gut microbiota-BA axis,which may serve as potential therapeutic targets for obesity-related disorders.

Selenoprotein-p and insulin resistance in children and adolescents with obesity

BACKGROUND Insulin resistance and obesity present significant challenges in pediatric populations.Selenoprotein P1(SEPP1)serves as a biomarker for assessing selenium levels in the body.While its association with metabolic syndrome is established in adults,its relevance in children remains underexplored.AIM To ascertain SEPP1 blood levels in children and adolescents diagnosed with obesity and to assess its correlation with insulin resistance and adiposity indices.METHODS 170 children participated in this study,including 85 diagnosed with obesity and an equal number of healthy counterparts matched for age and sex.Each participant underwent a comprehensive medical evaluation,encompassing a detailed medical history,clinical examination,and anthropometric measurements like waist circumference and waist-to-height ratio.Furthermore,routine blood tests were conducted,including serum SEPP1,visceral adiposity index(VAI),and Homeostatic Model Assessment of Insulin Resistance(HOMA-IR)level.RESULTS Our findings revealed significantly lower serum SEPP1 levels in children with obesity compared to their healthy peers.Moreover,notable negative correlations were observed between serum SEPP1 levels and body mass index,VAI,and HOMA-IR.CONCLUSION The study suggests that SEPP1 could serve as a valuable predictor for insulin resistance among children and adolescents diagnosed with obesity.This highlights the potential utility of SEPP1 in pediatric metabolic health assessment and warrants further investigation.

The success of sleeve gastrectomy in the management of metabolic syndrome and obesity

The rapid reversal of diabetes,hypertension,hyperlipidaemia and obesity by surgical means has challenged accepted doctrines regarding the management of metabolic syndrome.Sleeve gastrectomy,which developed initially as a preparatory procedure for biliopancreatic diversion with duodenal switch,has seen an exponential rise in popularity as an effective lone laparoscopic bariatric procedure.Superior excess weight loss,a low complication rate,and excellent food tolerance,combined with a short hospital stay,have made this the procedure of choice for patients and surgeons across the globe.High volume centres nurture the ongoing development of experienced and specialized teams,pathways and regimens.Optimum surgical outcomes allow minimization of metabolic syndrome,reducing cardiovascular and cerebrovascular risk.

Association between childhood obesity and gut microbiota:16S rRNA gene sequencing-based cohort study

BACKGROUND This study aimed to identify characteristic gut genera in obese and normal-weight children(8-12 years old)using 16S rDNA sequencing.The research aimed to provide insights for mechanistic studies and prevention strategies for childhood obesity.Thirty normal-weight and thirty age-and sex-matched obese children were included.Questionnaires and body measurements were collected,and fecal samples underwent 16S rDNA sequencing.Significant differences in body mass index(BMI)and body-fat percentage were observed between the groups.Analysis of gut microbiota diversity revealed lowerα-diversity in obese children.Differences in gut microbiota composition were found between the two groups.Prevotella and Firmicutes were more abundant in the obese group,while Bacteroides and Sanguibacteroides were more prevalent in the control group.AIM To identify the characteristic gut genera in obese and normal-weight children(8-12-year-old)using 16S rDNA sequencing,and provide a basis for subsequent mechanistic studies and prevention strategies for childhood obesity.METHODS Thirty each normal-weight,1:1 matched for age and sex,and obese children,with an obese status from 2020 to 2022,were included in the control and obese groups,respectively.Basic information was collected through questionnaires and body measurements were obtained from both obese and normal-weight children.Fecal samples were collected from both groups and subjected to 16S rDNA sequencing using an Illumina MiSeq sequencing platform for gut microbiota diversity analysis.RESULTS Significant differences in BMI and body-fat percentage were observed between the two groups.The Ace and Chao1 indices were significantly lower in the obese group than those in the control group,whereas differences were not significant in the Shannon and Simpson indices.Kruskal-Wallis tests indicated significant differences in unweighted and weighted UniFrac distances between the gut microbiota of normal-weight and obese children(P<0.01),suggesting substantial disparities in both the species and quantity of gut microbiota between the two groups.Prevotella,Firmicutes,Bacteroides,and Sanguibacteroides were more abundant in the obese and control groups,respectively.Heatmap results demonstrated significant differences in the gut microbiota composition between obese and normal-weight children.CONCLUSION Obese children exhibited lowerα-diversity in their gut microbiota than did the normal-weight children.Significant differences were observed in the composition of gut microbiota between obese and normal-weight children.

Central Obesity and Metabolic Risk Factors in Middle-aged Chinese

Objective Central obesity is considered to be a central component of metabolic syndrome. Waist circumference （WC） has been widely used as a simple indicator of central obesity. This study is aimed to evaluate the sensitivity of WC cut-off values for predicting metabolic risk factors in middle-aged Chinese. Methods The study involved 923 subjects aged according to the Chinese Joint Committee for 40-65 years. The metabolic risk factors were defined Developing Chinese Guidelines on Prevention and Treatment of Dyslipidemia in Adults. WC cut-off 85-90 cm and 〉90 cm were used as cut-off values of central pre-obesity and central obesity in males, respectively, while WC 80-85 cm and 〉85 cm were used as cut-off values of central pre-obesity and central obesity in females. Results First, WC values corresponding to body mass index （BMI） 24 kg/m2 and visceral fat area （VFA） 80 cm2 were 88.55 cm and 88.51 cm in males, and 82.46 cm and 82.52 cm in females respectively. Second, receiver operating characteristic curves showed that the optimal WC cut-off of value was 88.75 cm in males, higher than that in females （81.75 cm）. Third, the subjects with higher WC values were more likely to have accumulating metabolic risk factors. The prevalence of metabolic risk factors increased linearly and significantly in relation to WC levels. Conclusion WC cut-off values of central pre-/central obesity are optimal to predict multiple metabolic risk factors.

Metabolic effects of obesity:A review

With the many recent advances in the biomedical world,vast changes are taking place in our growing knowledge of the physiological aspects of almost all the tissues and organs of the human body.One of the most prevalent topics of discussion is the question of obesity and its effect on the metabolic changes in the human body.The original classical role of adipose tissue as an energy storage organ has been greatly modified.We now know that it is an endocrine organ,producing adipokines like leptin,adiponectin,visfatin,resistin,apelin,etc,which modulate metabolic processes in the body.Since obesity is associated with an increase in the adipose tissue mass,these hormones may be expected to be produced in increased concentrations and may thus have a significant impact on the macronutrient metabolism.Further,these adipokines may interact with long term energy modulators like insulin.Even though the scientific community has started unravelling the mysteries of the close linkage between obesity,its hormones and their physiological effects,a lot still remains to be discovered.The present discussion makes an attempt to trace the basic modern day concepts of the role of obesity in various metabolic processes.

Low serum amylase and obesity, diabetes and metabolic syndrome: A novel interpretation

For the last decade, low serum amylase(hypoamylasemia) has been reported in certain common cardiometabolic conditions such as obesity, diabetes(regardless of type), and metabolic syndrome, all of which appear to have a common etiology of insufficient insulin action due to insulin resistance and/or diminished insulin secretion. Some clinical studies have shown that salivary amylase may be preferentially decreased in obese individuals, whereas others have revealed that pancreatic amylase may be preferentially decreased in diabetic subjects with insulin dependence. Despite this accumulated evidence, the clinical relevance of serum, salivary, and pancreatic amylase and the underlying mechanisms have not been fully elucidated. In recent years, copy number variations(CNVs) in the salivary amylase gene(AMY1), which range more broadly than the pancreatic amylase gene(AMY2A and AMY2B), have been shown to be well correlated with salivary and serum amylase levels. In addition, low CNV of AMY1, indicating low salivary amylase, was associated with insulin resistance, obesity, low taste perception/satiety, and postprandial hyperglycemia through impaired insulin secretion at early cephalic phase. In most populations, insulin-dependent diabetes is less prevalent(minor contribution) compared with insulin-independent diabetes, and obesity is highly prevalent compared with low body weight. Therefore, obesity as a condition that elicits cardiometabolic diseases relating to insulin resistance(major contribution) may be a common determinant for low serum amylase in a general population. In this review, the novel interpretation of low serum, salivary, and pancreas amylase is discussed in terms of major contributions of obesity, diabetes, and metabolic syndrome.

Metabolic liver disease of obesity and role of adipose tissue in the pathogenesis of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease （NAFLD） is an increasingly recognized cause of liver-related morbidity and mortality. It can develop secondary to numerous causes but a great majority of NAFLD cases occur in patients who are obese or present with other components of metabolic syndrome （hypertension, dyslipidemia, diabetes）. This is called primary NAFLD and insulin resistance plays a key role in its pathogenesis. Obesity is characterized by expanded adipose tissue, which is under a state of chronic inflammation. This disturbs the normal storage and endocrine functions of adipose tissue. In obesity, the secretome （adipokines, oytokines, free fatty acids and other lipid moieties） of fatty tissue is amplified, which through its autocrine, paracrine actions in fat tissue and systemic effects especially in the liver leads to an altered metabolic state with insulin resistance （IR）. IR leads to hyperglycemia and reactive hyperinsulinemia, which stimulates lipid-accumulating processes and impairs hepatic lipid metabolism. IR enhances free fatty acid delivery to liver from the adipose tissue storage due to uninhibited lipolysis. These changes result in hepatic abnormal fat accumulation, which may initiate the hepatic IR and further aggravate the altered metabolic state of whole body. Hepatic steatosis can also be explained by the fact that there is enhanced dietary fat delivery and physical inactivity. IR and NAFLD are also seen in various lipodystrophic states in contrary to popular belief that these problems only occur due to excessive adiposity in obesity. Hence, altered physiology of adipose tissue is central to development of IR, metabolic syndrome and NAFLD.

Different metabolic/obesity phenotypes are differentially associated with development of prediabetes in adults: Results from a 14-year cohort study

BACKGROUND The risk of developing prediabetes based on the metabolic/obesity phenotypes has been poorly investigated. AIM To examine the association of baseline metabolic/obesity phenotypes and their changes over time with the risk of prediabetes development. METHODS In a population-based cohort study, 1741 adults (aged > 19 years) with normal blood glucose were followed for 14 years. Anthropometric and biochemical measures were evaluated regularly during the follow-up period. According to body mass index and metabolic health status, participants were categorized into four groups: Metabolically healthy normal weight (MHNW), metabolically healthy obese (MHO), metabolically unhealthy normal weight (MUNW) and metabolically unhealthy obese (MUO). Multivariable Cox regression analysis was used to measure the risk of prediabetes according to the baseline metabolic/obesity phenotype and their changes during the follow-up. RESULTS In the whole population with a mean (95CCI for mean) follow up duration of 12.7 years (12.6-12.9), all three MUNW, MHO, MUO groups were at higher risk for developing prediabetes compared to the MHNW group (P = 0.022). The MUNW group had the highest risk for developing prediabetes (hazard ratio (HR): 3.84, 95%CI: 1.20, 12.27). In stratified analysis by sex, no significant association was found in men, while women in the MUNW group were at the greatest risk for prediabetes (HR: 6.74, 95%CI: 1.53, 29.66). Transforming from each phenotype to MHNW or MHO was not related to the risk of prediabetes development, whereas transforming from each phenotype to MUO was associated with an increased risk of prediabetes (HR > 1;P < 0.05). CONCLUSION Our findings indicate that MHO is not a high risk, unless it transforms into MUO over time. However, people in the MUNW group have the greatest risk for developing prediabetes, and therefore, they should be screened and treated.

Obesity and cardiometabolic disease risk factors among US adolescents with disabilities

AIM: To generate prevalence estimates of weight status and cardiometabolic disease risk factors among adolescents with and without disabilities.METHODS: Analysis of the 1999-2010 National Health and Nutrition Examination Survey data was conducted among 12-18 years old with(n = 256) and without disabilities(n = 5020). Mean values of waist circumference, fasting glucose, high-density-lipoprotein cholesterol, triglycerides, systolic and diastolic blood pressure and metabolic syndrome(Met S, ≥ 3 risk factors present) were examined by the following standardized body mass index(BMI) categories for those with and without disabilities; overweight(BMI ≥ 85th- < 95 th percentile for age and sex), obesity(BMI ≥ 95 th percentile) and severe obesity(BMI ≥35 kg/m2). Linear regression models were fit with each cardiometabolic disease risk factor independently as continuous outcomes to show relationships with disability status. RESULTS: Adolescents with disabilities were significantlymore likely to be overweight(49.3%), obese(27.6%) and severely obese(12%) vs their peers without disabilities(33.1%, 17.5% and 3.6%, respectively, P ≤ 0.01 for all). A higher proportion of overweight, obese and severely obese children with disabilities had abnormal SBP, fasting lipids and glucose as well as Met S(18.9% of overweight, 32.3% of obese, 55% of severely obese) vs their peers without disabilities(9.7%, 16.8%, 36.3%, respectively). US adolescents with disabilities are over three times as likely to have Met S(OR = 3.45, 95%CI: 1.08-10.99, P = 0.03) vs their peers with no disabilities.CONCLUSION: Results show that adolescents with disabilities are disproportionately affected by obesity and poor cardiometabolic health vs their peers with no disabilities. Health care professionals should monitor the cardiometabolic health of adolescents with disabilities.

Non-alcoholic fatty liver disease and obesity: Biochemical, metabolic and clinical presentations

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease in the world. Presentation of the disease ranges from simple steatosis to non-alcoholic steatohepatitis (NASH). NAFLD is a hepatic manifestation of metabolic syndrome that includes central abdominal obesity along with other components. Up to 80% of patients with NAFLD are obese, defined as a body mass index (BMI) > 30 kg/m2. However, the distribution of fat tissue plays a greater role in insulin resistance than the BMI. The large amount of visceral adipose tissue (VAT) in morbidly obese (BMI > 40 kg/m2) individuals contributes to a high prevalence of NAFLD. Free fatty acids derived from VAT tissue, as well as from dietary sources and de novo lipogenesis, are released to the portal venous system. Excess free fatty acids and chronic low-grade inflammation from VAT are considered to be two of the most important factors contributing to liver injury progression in NAFLD. In addition, secretion of adipokines from VAT as well as lipid accumulation in the liver further promotes inflammation through nuclear factor kappa B signaling pathways, which are also activated by free fatty acids, and contribute to insulin resistance. Most NAFLD patients are asymptomatic on clinical presentation, even though some may present with fatigue, dyspepsia, dull pain in the liver and hepatosplenomegaly. Treatment for NAFLD and NASH involves weight reduction through lifestyle modifications, anti-obesity medication and bariatric surgery. This article reviews the available information on the biochemical and metabolic phenotypes associated with obesity and fatty liver disease. The relative contribution of visceral and liver fat to insulin resistance is discussed, and recommendations for clinical evaluation of affected individuals is provided.