Low-Calorie Ketogenic Diet with Continuous Positive Airway Pressure to Alleviate Severe Obstructive Sleep Apnea Syndrome in Patients with Obesity Scheduled for Bariatric/Metabolic Surgery: a Pilot, Prospective, Randomized Multicenter Comparative Study

Beyond epilepsy management: A narrative review of the health effects of ketogenic diets

The Ketogenic diet (KD), characterized by a low-carbohydrate/high-fat intake, induces a state of ketosis, where the body primarily relies on using fat for energy instead of carbohydrates. This diet is historically used in epilepsy management. Recently, KD has been the subject of increased research and public interest for its additional potential health effects. This narrative review offers an overview of the potential health effects of the KD and outlines its clinical implications. We searched PubMed and Google Scholar for randomized controlled trials (RCTs) published between 2014 and 2024, exploring the health effects of KD in humans beyond epilepsy management. We included 34 RCTs on various diseases and health outcomes. The findings highlight that the KD is particularly effective for weight loss and metabolic health, making it especially relevant for individuals with obesity and metabolic syndrome, both of which are of major public health concern worldwide. Additionally, the KD shows significant promise in managing neurological disorders, particularly Alzheimer's and Parkinson's diseases, with studies suggesting improvements in cognitive function and disease progression. The diet has also been shown to reduce the frequency and severity of migraines, offering potential relief for those affected. Furthermore, the KD may improve reproductive health, though more research is needed in this area. While the diet demonstrates benefits in these key areas, potential risks, including impacts on kidney and liver function, nutrient deficiencies, and adverse pregnancy outcomes, must be considered. The majority of included RCTs were of limited sample size and duration. Therefore, KD may be a promising dietary approach for weight control, neurological disease, and metabolic syndrome management, yet individualized guidance based on the medical history of each patient is crucial. Further research with larger samples and longer follow-up duration is needed to address existing gaps and improve our understanding of the health effects of the KD.

Preoperative weight loss by noninvasive approach in patients with obesity scheduled for bariatric and metabolic surgery: an update narrative review of indications and results available until 2024

Metabolic and bariatric surgery (MBS) is the most effective treatment for severe obesity and its metabolic complications. Currently, most MBSs are performed laparoscopically. However, high weight associated with an enlarged liver (especially the left lobe liver section, LLLS) may complicate the technical aspects of this surgery. Therefore, before MBS, moderate preoperative weight loss (PreopWL), and reduction in LLLS are desirable. Moreover, studies are inconclusive regarding which is the best approach to apply. This narrative review aimed to describe the current scientific evidence on the effect of a noninvasive approach, such as dietary or pharmacotherapy or space-occupying devices on PreopWL, peri-operative complications, hospital length of stay, and post-operative complications in patients with obesity scheduled for MBS. We conducted a literature search and screening for relevant publications from January 2010 to June 2024. We found that PreopWL before MBS is helpful for both patients and surgeons, as it leads to various benefits, such as a decrease in body weight and LLLS size, a lower risk of intra- and post-operative complications, shorter surgery times, and reduced hospital stays. In this context, concerning dietary approaches, several dietary protocols have been introduced over time, among which very low-calorie diets and very low energy ketogenic therapy are widely prescribed; however, larger randomized-controlled trials (RCTs) with well-defined dietary protocols are necessary to make definitive conclusions. Obesity management medications, such as the lipase inhibitor orlistat, phentermine/topiramate, naltrexone/bupropion, the glucagon-like peptide-1 receptor agonists (GLP-1RAs) liraglutide and semaglutide, and the novel dual glucose dependent insulinotropic peptide (GIP)/GLP-1 receptor agonist tirzepatide, has shown to be effective in promoting PreopWL before MBS; however, larger, well-designed RCTs are needed to establish optimal treatment protocols and assess their true benefits in patients scheduled for MBS. Space-occupying devices such as the swallowable intragastric balloon and hydrogel capsules, represent a promising tools but further research is essential to confirm their role.

Advancing Obesity Management: the Very Low-Energy Ketogenic therapy (VLEKT) as an Evolution of the "Traditional" Ketogenic Diet

PURPOSE OF REVIEW

This narrative review comprehensively analyzes VLEKT as an advanced nutritional strategy for obesity management. The focus is on the beneficial effects on key disease organs, such as adipose tissue and liver, as well as the modulation of intestinal permeability and its fundamental role in influencing the gut microbiota and inflammatory pathways.

RECENT FINDINGS

The impact of VLEKT on obesity-related comorbidities, including metabolic syndrome, cardiovascular disease, endocrine disorders, metabolic dysfunction-associated steatotic liver disease (MASLD), neurological disorders, and kidney alterations, is also investigated. Moreover, to assess its wider application in obesity treatment, the combination of ketogenic regimes with additional strategies such as physical activity, bariatric surgery, and digital health technologies is examined. Despite promising clinical results, adherence to VLEKT and potential nutritional deficiencies require careful follow-up and individualized programming monitored by specialists. Future research should focus on elucidating the molecular mechanisms underlying the effects on physiological systems, and long-term safety. Nevertheless, VLEKT is an innovative approach to obesity treatment, offering a target-oriented and highly effective strategy for people fighting against overweight and its associated medical complications. Obesity is a multifactorial and chronic disease associated with numerous comorbidities; given its increasing prevalence, effective and personalized intervention strategies are crucial to inhibit the "obesity pandemic" according to a "food re-educational" protocol. Among dietary interventions, the ketogenic diet (KD) has attracted attention for its effectiveness in weight management and metabolic benefits. A variant, the very low-calorie ketogenic diet (VLCKD), more recently defined as very low-energy ketogenic diet (VLEKD), combines the metabolic benefits of ketosis with substantial calorie restriction, improving overall health.

Preliminary Evidence Suggests That a 12-Week Treatment with Tirzepatide Plus Low-Energy Ketogenic Therapy Is More Effective than Its Combination with a Low-Calorie Diet in Preserving Fat-Free Mass, Muscle Strength, and Resting Metabolic Rate in Patients with Obesity

Background: Tirzepatide (TZP), a unimolecular dual agonist targeting glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptors, is a promising weight loss agent in obesity. The preservation of metabolically active fat-free mass (FFM), muscle strength (MS), and resting metabolic rate (RMR) is essential for optimizing fat mass (FM) reduction. Although TZP is typically combined with a low-calorie diet (LCD), its impact on FFM is uncertain, and studies on MS and RMR are lacking. Evidence suggests that Low-Energy Ketogenic Therapy (LEKT) may reduce FM while preserving FFM, MS, and RMR. Therefore, this study aimed to compare the effects of an LEKT and an LCD, both combined with TZP, on body weight (BW), FM, FFM, MS, and RMR in patients with obesity. Methods: We prospectively compared the effects of TZP combined with either an LCD or LEKT in 60 patients with obesity (n = 30 per group) over 12 weeks. BW, FM, FFM, MS, and RMR were measured at baseline and after 12 weeks. Clinical parameters, an assessment of dietary compliance, and side effects were also evaluated. Results: At 12-week follow-up, both groups showed a significant BW reduction from baseline (TZP+LEKT, p = 0.0289; TZP+LCD, p = 0.0278), with no significant intergroup difference (p = 0.665). Similarly, FM decreased significantly in both cohorts (TZP+LEKT, p < 0.001; TZP+LCD, p = 0.0185), with the TZP+LEKT group achieving a greater FM loss (p = 0.042). However, the TZP+LCD group exhibited significant declines from baseline in FFM (p = 0.0284), MS (p = 0.0341), and RMR (p < 0.001), whereas we did not observe any significant changes in FFM (p = 0.487), MS (p = 0.691), and RMR (p = 0.263) in the TZP+LEKT group. Intergroup direct comparisons confirmed that the TZP+LCD group experienced significantly greater reductions in FFM (p = 0.0388), MS (p = 0.046), and RMR (p = 0.019). Conclusions: Based on the findings of these preliminary data, we are able to support the hypothesis that TZP+LEKT seems to be superior to TZP+LCD in promoting FM reduction while preserving FFM, MS, and RMR in patients with obesity.

Association between pollinosis and obstructive sleep apnea hypopnea syndrome in the US population: evidence from the NHANES database 2005-2018

BACKGROUND

Rhinobyon and inflammation associated with pollinosis may elevate the risk of obstructive sleep apnea hypopnea syndrome (OSAHS). However, the exact nature of this association remains unclear, particularly in large-scale populations. This study aimed to examine the relationship between pollinosis and OSAHS using data from the National Health and Nutrition Examination Survey (NHANES).

METHODS

Data from the NHANES spanning 2005 to 2018 were analyzed. Three multivariate generalized linear models (GLMs) were employed to explore the relationship between pollinosis and OSAHS: one unadjusted model, one minimally adjusted model, and one fully adjusted model. Stratified analyses were conducted to assess the impact of pollinosis and other covariates on OSAHS. Additionally, the study incorporated K-Nearest Neighbors (KNN) and smoothed curves to refine the analysis.

RESULTS

The study identified significant demographic differences between groups in factors such as pollinosis, age, gender, weight (WT), body mass index (BMI), waist circumference (WC), protein, and fat. In three adjusted models, a consistent association was observed between pollinosis and OSAHS. Specifically, Model 1 showed an odds ratio (OR) of 1.31 [95% confidence interval (CI): 1.16-1.48, P < 0.001], Model 2 revealed an OR of 1.35 (95% CI: 1.19-1.54, P < 0.001), and Model 3 indicated an OR of 1.29 (95% CI: 1.10-1.50, P = 0.002), suggesting that the relationship between pollinosis and OSAHS remained robust despite the inclusion of other covariates. Risk stratification confirmed that pollinosis was a risk factor for OSAHS (OR = 1.28, 95% CI: 1.10-1.50, P = 0.002). The KNN model further supported the utility of pollinosis as a diagnostic marker for OSAHS. Smoothing curves also demonstrated a positive correlation between pollinosis prevalence and OSAHS incidence.

CONCLUSION

This study established pollinosis as a risk factor for OSAHS, emphasizing the need for vigilance in monitoring and managing OSAHS in individuals with pollinosis risk.

Effects of ketogenic and low-carbohydrate diets on the body composition of adults with overweight or obesity: A systematic review and meta-analysis of randomised controlled trials

BACKGROUND AND AIMS

More than one-third of individuals are overweight and obese in the world. Their risks of chronic health conditions are increased, which places additional burden on their family, caregivers, and healthcare system. Dietary modification is widely used for overweight and obese individuals. We investigated the effects of ketogenic diet (KD) and low-carbohydrate diet (LCD) in improving body weight (BW), body mass index (BMI), fat mass (FM), and body fat percentage (BFP) in overweight or obese individuals.

METHODS

A three-step approach was adopted for searching relevant randomised controlled trials (RCTs) across five electronic databases. Two reviewers conducted the screening, review, and quality appraisal independently. A random-effects model was used because of variations in intervention and participant characteristics. Sensitivity and subgroup analyses were conducted to assess heterogeneity and variations in the results, respectively.

RESULTS

Thirty-three RCTs involving 2821 individuals were included. Overall meta-analysis results indicated that KD/LCD significantly reduced BW, BMI, and BFP, but not FM, in individuals with a carbohydrate intake of ≤100 g/d. Subgroup analyses revealed significant improvements in BW, BMI, and FM in individuals on KD/LCD for ≥1 month and in all parameters for those with a carbohydrate intake of ≤50 g/d. High statistical heterogeneity was noted because of variations in interventions and participant characteristics.

CONCLUSION

Adults with overweight or obesity should consume KD/LCD for ≥1 month and limit carbohydrate intake to ≤50 g/d. Further multicentre or multicountry RCTs are needed to improve the generalisability of our findings. We recommend integrating text messaging and evidence-based information to support interventions and ensuring stringent medical supervision throughout the intervention.

PROSPERO REGISTRATION NUMBER

CRD42022353074.

Preventing and Managing Pre- and Postoperative Micronutrient Deficiencies: A Vital Component of Long-Term Success in Bariatric Surgery

Bariatric surgery (BS) is an effective treatment for severe obesity and its related comorbidities, such as type 2 diabetes and hypertension. However, the anatomical and physiological changes associated with these procedures significantly increase the risk of preoperative and postoperative micronutrient deficiencies, which can lead to severe complications such as anemia, osteoporosis, and neurological disorders. This narrative review examines the prevalence and clinical implications of micronutrient deficiencies in BS patients, as well as evidence-based strategies for their prevention and management. The most common deficiencies include iron, vitamin B12, folate, calcium, vitamin D, and fat-soluble vitamins (A, E, and K). Procedures with a hypoabsorptive component, such as Roux-en-Y gastric bypass (RYGB) and biliopancreatic diversion with duodenal switch (BPD/DS), pose higher risks of deficiencies compared to restrictive procedures like sleeve gastrectomy (SG). Effective strategies involve the preoperative correction of deficiencies, continuous monitoring, and tailored supplementation. However, long-term adherence to supplementation tends to decrease over time, influenced by behavioral and socioeconomic factors. Hence, preventing and managing micronutrient deficiencies are crucial for the long-term success of BS. While current guidelines provide valuable recommendations, many are based on low-certainty evidence, underscoring the need for more robust studies. A multidisciplinary approach, combined with innovative strategies, such as telemedicine, can enhance adherence and achieve sustainable clinical outcomes.

Intentional weight reduction before surgery - A systematic review

INTRODUCTION

Obesity may increase complexity of surgical procedures and increase the risk of perioperative complications. Weight reduction by the use of low energy diet (LED, ≤1200 kcal/day) or very low energy diet (VLED, ≤800 kcal/day) can reduce postoperative complications after bariatric surgery, but for most other types of surgery the evidence for its use remains uncertain. The aim of this systematic review was therefore to evaluate the scientific evidence in general for this routine.

METHODS

The Medline, Embase, Web of Science and Cochrane databases were searched up until November 20, 2024 using the Cochrane risk of bias assessment tool for observational studies and the NIH quality assessment of controlled intervention studies for randomized trials. Operation time, surgeon's perceived difficulty, intraoperative complications, postoperative complications and relevant efficacy measures for specific procedures were considered as endpoints. A random-effects model was used to pool effect sizes for the main analyses.

RESULTS

A total of 7053 studies were identified. After screening by title and abstract, followed by full text, 18 studies (9 RCTs and 9 observational studies) remained for the analyses including 854 patients who received the intervention and 979 controls. Preoperative LED/VLED resulted in an overall shorter operation time (standard mean difference 0.36, 95 % CI 0.14-0.59, p = 0.002), and reduced risk of postoperative complications after bariatric surgery, cholecystectomy, colorectal surgery and hernia repair (pooled RR 0.63, 95%CI 0.51-0.79, p < 0.001). Heterogeneity between studies was high for operation time but very low for complications. No difference was seen for intraoperative complications, while the data did not allow further analyses on perceived difficulty of surgery or efficacy outcomes.

CONCLUSION

The results support the use of LED/VLED for short-term preoperative weight reduction in patients with obesity planned for bariatric surgery and for those undergoing cholecystectomy, colorectal surgery and hernia repair. Further studies including a comparable control group are needed to evaluate its routine use for other surgical procedures.

REGISTRATION

The protocol of this study was preregistered at the International Prospective Register of Systematic Reviews, PROSPERO.

The effect of a ketogenic diet on inflammation-related markers: a systematic review and meta-analysis of randomized controlled trials

CONTEXT

Despite the important role of inflammation-related factors on the occurrence of chronic diseases, there is still conflicting evidence about the effects of the ketogenic diet (KD) on these factors.

OBJECTIVE

In order to obtain a better viewpoint, this study aimed to comprehensively investigate the effects of a KD on inflammation-related markers.

DATA SOURCES

To find pertinent randomized controlled trials up to August 2023, databases including PubMed/Medline, Web of Science, Scopus, Cochrane Library, and Embase were searched.

DATA EXTRACTION

This study included all randomized controlled trials investigating the effects of a KD on C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, IL-8, and IL-10 levels. Pooled weighted mean difference (WMD) and 95% confidence intervals (CIs) were achieved by random-effects model analysis for the best estimation of outcomes.

DATA ANALYSIS

Forty-four studies were included in this article. The pooled findings showed that a KD has an effect on lowering TNF-α (WMD: -0.32 pg/mL; 95% CI: -0.55, -0.09; P = 0.007) and IL-6 (WMD: -0.27 pg/mL; 95% CI: -0.52, -0.02; P = 0.036) compared with control groups. However, no significant effect was reported for others inflammation marker-related levels. The results of the subgroup analysis showed that, in trials following the KD for ≤8 weeks and in people aged ≤50 years, the reduction in TNF-α levels was significantly higher than in other groups. In addition, in people with a body mass index greater than 30 kg/m2 compared to a body mass index ≤30 kg/m2, IL-6 levels decreased to a greater extent after receiving the KD.

CONCLUSIONS

Consequently, adherence to a KD appears to improve some markers associated with inflammation, including TNF-α and IL-6.

Safety and Effectiveness of a 4-Week Diet on Low-Carb Ready-to-Eat Ketogenic Products as Preoperative Care Treatment in Patients Scheduled for Metabolic and Bariatric Surgery

Before metabolic and bariatric surgery (MBS), moderate weight loss and liver left lateral section (LLLS) volume reduction are desirable. Low-carb ketogenic diet-induced weight loss before MBS has been shown to have beneficial effects on the reduction in body weight (BW) and LLLS. However, the nutritional protocol of low-carb ketogenic diet may be hard to keep for prolonged periods due to the lack of sweet taste. Furthermore, transitioning to a low-carb ketogenic diet can cause people to crave foods that are restricted in the ketogenic diet, such as cookies, bread, pasta, and bagels. Therefore, many ready-to-eat low-carb ketogenic products (RLCKP) that mimic carbohydrate-rich foods despite a low-carb composition have been provided to make it easier for the patients to adopt a low-carb lifestyle. To date, there are no studies describing the dietary protocol for efficient and safe use of pre-operative RLCKP in terms of weight and LLLS volume reduction in patients with obesity scheduled for MBS. Therefore, the aim of this study was to assess the safety and effectiveness of a 4-week diet using RLCKP in reducing BW and LLLS volume in patients with obesity scheduled for MBS. Patients with obesity (n = 42) with a mean body mass index (BMI) of 42.4 ± 9.2 kg/m2 scheduled for MBS underwent a 4-week preoperative RLCKP diet intervention. Their weight, LLLS volume, and biochemical and metabolic parameters were measured before and after the diet. Patient compliance was assessed by the presence of ketonuria and weight loss. Qualitative methods (5-point Likert questionnaire) were used to measure diet acceptability and side effects. All patients completed the study. We observed highly significant decreases in BW (-6.5%, p < 0.001), and LLLS volume (-22.3%, p < 0.001) and an amelioration of patient clinical status. All patients showed a high frequency of acceptability and compliance in following the diet. No adverse side effects were reported. Based on our findings, we were able to support the hypothesis that a 4-week preoperative RLCKP diet is safe and effective in reducing BW, and LLLS volume in patients with obesity scheduled for MBS.

Plant-based and vegetarian diets are associated with reduced obstructive sleep apnoea risk

Introduction

Obstructive sleep apnoea (OSA) and obesity commonly coexist. Weight loss and exercise are recommended management options for OSA. However, most of the current evidence on diet and OSA is focused on calorie restriction rather than diet quality. The aim of the present study was to determine the association of plant-based dietary indices (PDI) with OSA risk.

Methods

Cross-sectional data from 14 210 participants of the National Health and Nutrition Examination Survey who provided dietary information using the 24-hour recall method were used. PDI - including healthy (hPDI), unhealthy (uPDI) and pro-vegetarian diet index (PVDI) - were determined. OSA risk was determined using the STOP-BANG questionnaire. Logistic regression was used to determine the relationship between dietary indices and OSA risk.

Results

Higher adherence to PDI (odds ratio (OR)Q5 versus Q1=0.81; 95% confidence interval (CI): 0.66-1.00), hPDI (OR=0.83; 95% CI: 0.69-1.01) and PVDI (OR=0.84; 95% CI: 0.68-1.05) was inversely associated with OSA risk, whereas higher consumption of an unhealthy plant-based diet (OR=1.22; 95% CI: 1.00-1.49) was positively associated with OSA. Sex differences in estimates were observed for PDI in males (OR=0.71; 95% CI: 0.56-0.90) versus females (OR=0.93; 95% CI: 0.68-1.28), hPDI in males (OR=0.90; 95% CI: 0.68-1.18) versus females (OR=0.77; 95% CI: 0.54-1.09) and uPDI in males (OR=1.13; 95% CI: 0.89-1.44) versus females (OR=1.42; 95% CI: 1.03-1.97) but not for PVDI.

Conclusions

Higher adherence to a healthy plant-based diet is associated with reduced OSA risk, while an unhealthy plant-based diet has a positive association. The magnitude of these associations differs by sex. Further longitudinal studies are warranted.

Ketogenic nutritional therapy (KeNuT)-a multi-step dietary model with meal replacements for the management of obesity and its related metabolic disorders: a consensus statement from the working group of the Club of the Italian Society of Endocrinology (SIE)-diet therapies in endocrinology and metabolism

PURPOSE

The ketogenic nutritional therapy (KeNuT) is an effective dietary treatment for patients with obesity and obesity-related comorbidities, including type 2 diabetes, dyslipidaemia, hypertension, coronary artery disease, and some type of cancers. However, to date an official document on the correct prescription of the ketogenic diet, validated by authoritative societies in nutrition or endocrine sciences, is missing. It is important to emphasize that the ketogenic nutritional therapy requires proper medical supervision for patient selection, due to the complex biochemical implications of ketosis and the need for a strict therapeutic compliance, and an experienced nutritionist for proper personalization of the whole nutritional protocol.

METHODS

This practical guide provides an update of main clinical indications and contraindications of ketogenic nutritional therapy with meal replacements and its mechanisms of action. In addition, the various phases of the protocol involving meal replacements, its monitoring, clinical management and potential side effects, are also discussed.

CONCLUSION

This practical guide will help the healthcare provider to acquire the necessary skills to provide a comprehensive care of patients with overweight, obesity and obesity-related diseases, using a multistep ketogenic dietary treatment, recognized by the Club of the Italian Society of Endocrinology (SIE)-Diet Therapies in Endocrinology and Metabolism.

Association of modifiable risk factors with obstructive sleep apnea: a Mendelian randomization study

BACKGROUND

The risk factors involved in obstructive sleep apnea (OSA) have not been clearly identified yet. We attempted to systematically investigate genetically predicted modifiable risk factors and lifestyle behaviors associated with OSA.

METHODS

The association between 34 risk factors and OSA was evaluated using the two-sample Mendelian randomization (MR). Genetic variants for risk factors were acquired from European-descent genome-wide studies. Data sources for OSA were extracted from FinnGen study with 16,761 cases and 201,194 controls. The primary analysis chosen was the inverse-variance weighted method.

RESULTS

MR analyses provide evidence of genetically predicted poor overall health rating (odds ratio (OR), 2.82; 95% confidence interval (CI), 1.95-4.08), nap during day (OR, 2.01; 95% CI, 1.37-2.93), high body mass index (BMI) (OR, 1.14; 95% CI, 1.09-1.19), increased body fat mass (OR, 1.83; 95% CI, 1.83-2.05), elevated body water mass (OR, 1.50; 95% CI, 1.31-1.70) and hypertension (OR, 1.81; 95% CI, 1.34-2.45) were associated with higher OSA risk, while high education level (OR, 0.55; 95% CI, 0.40-0.75) correlated with reduced OSA risk. Suggestive evidence was obtained for smoking and waist-to-hip ratio (WHR) with higher OSA odds, and vigorous physical activity, and HDL cholesterol with lower OSA odds. After adjusting for BMI using multivariable MR analysis, the effects of smoking, WHR, vigorous physical activity, and HDL-cholesterol were fully attenuated.

CONCLUSIONS

This MR study indicates that overall health rating, nap during day, BMI, body fat mass, body water mass, hypertension, and education are causally associated with the risk of OSA, which means that these modifiable risk factors are key targets for OSA prevention.

Ketogenic Diet and Multiple Health Outcomes: An Umbrella Review of Meta-Analysis

Numerous studies have examined the effects of ketogenic diets (KD) on health-related outcomes through meta-analyses. However, the presence of biases may compromise the reliability of conclusions. Therefore, we conducted an umbrella review to collate and appraise the strength of evidence on the efficacy of KD interventions. We conducted a comprehensive search on PubMed, EMBASE, and the Cochrane Database until April 2023 to identify meta-analyses that investigated the treatment effects of KD for multiple health conditions, which yielded 23 meta-analyses for quantitative analyses. The evidence suggests that KD could increase the levels of low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C), the respiratory exchange rate (RER), and could decrease total testosterone and testosterone levels (all p-random effects: <0.05). The combination of KD and physical activity can significantly reduce body weight and increase the levels of LDL-C and cortisol. In addition, KD was associated with seizure reduction in children, which can be explained by the ketosis state as induced by the diet. Furthermore, KD demonstrated a better alleviation effect in refractory childhood epilepsy, in terms of median effective rates for seizure reduction of ≥50%, ≥90%, and seizure freedom. However, the strength of evidence supporting the aforementioned associations was generally weak, thereby challenging their credibility. Consequently, future studies should prioritize stringent research protocols to ascertain whether KD interventions with longer intervention periods hold promise as a viable treatment option for various diseases.

A Dietary and Lifestyle Intervention Improves Treatment Adherence and Clinical Outcomes in Overweight and Obese Patients with Obstructive Sleep Apnea: A Randomized, Controlled Trial

The study's objective was to assess the impact of Mediterranean diet/lifestyle interventions for weight loss on positive airway pressure (PAP) adherence, body mass index (ΒΜΙ), sleepiness, and blood pressure measurements (BP) in patients with obstructive sleep apnea (OSA). We designed a randomized, controlled trial, including overweight and obese patients with moderate to severe OSA, randomized to standard care (SCG, n = 37) or a Mediterranean diet group (MDG, n = 37). The SCG received healthy lifestyle advice, while the MDG underwent a 6-month behavioral intervention aiming to enhance weight loss and adherence to a Mediterranean diet. PAP adherence, BMI, Epworth Sleepiness Scale (ESS), and BP measurements were evaluated pre- and post-intervention. Post-intervention PAP use was higher in the MDG compared to the SCG (6.1 vs. 5.4, p = 0.02). Diet/lifestyle intervention was one of the most significant predictive factors for PAP adherence (OR = 5.458, 95% CI = 1.144-26.036, p = 0.03). The SCG demonstrated a rise in BMI, while the MDG displayed a decline (0.41 vs. -0.75, p = 0.02). The MDG also demonstrated a substantial reduction in adjusted SBP (-5.5 vs. 2.8, p = 0.014) and DBP (-4.0 vs. 2.5, p = 0.01). Ultimately, incorporating a dietary/lifestyle intervention with standard care yields superior PAP adherence, BMI, and BP measurements in contrast to standard care alone, emphasizing the advantages of dedicating more time and support within the MDG.

The Ketogenic Diet and Cardiovascular Diseases

The most common and increasing causes of death worldwide are cardiovascular diseases (CVD). Taking into account the fact that diet is a key factor, it is worth exploring this aspect of CVD prevention and therapy. The aim of this article is to assess the potential of the ketogenic diet in the prevention and treatment of CVD. The article is a comprehensive, meticulous analysis of the literature in this area, taking into account the most recent studies currently available. The ketogenic diet has been shown to have a multifaceted effect on the prevention and treatment of CVD. Among other aspects, it has a beneficial effect on the blood lipid profile, even compared to other diets. It shows strong anti-inflammatory and cardioprotective potential, which is due, among other factors, to the anti-inflammatory properties of the state of ketosis, the elimination of simple sugars, the restriction of total carbohydrates and the supply of omega-3 fatty acids. In addition, ketone bodies provide "rescue fuel" for the diseased heart by affecting its metabolism. They also have a beneficial effect on the function of the vascular endothelium, including improving its function and inhibiting premature ageing. The ketogenic diet has a beneficial effect on blood pressure and other CVD risk factors through, among other aspects, weight loss. The evidence cited is often superior to that for standard diets, making it likely that the ketogenic diet shows advantages over other dietary models in the prevention and treatment of cardiovascular diseases. There is a legitimate need for further research in this area.

Gender and Liver Steatosis Discriminate Different Physiological Patterns in Obese Patients Undergoing Bariatric Surgery: Obesity Center Cohort

BACKGROUND

Obesity is a major public health problem worldwide. Bariatric surgery can reduce body weight, and it is one of the better ways to improve metabolic disease and lifestyle. The aim of this study was to explore a new cohort of patients with obesity and evaluate the gender differences and the steatosis status within the gender group.

METHODS

A cohort of 250 adult obese patients with BMI ≥ 30 and age >18 years, eligible for gastric bariatric surgery at Pineta Grande Hospital, Castel Volturno (Italy) was studied.

RESULTS

The prevalence in women was higher (72.40%) than men (27.60%). Overall, results indicated many statistically significant gender differences in hematological and clinical parameters. Analysis of the subcohorts based on the severity of steatosis revealed differences of this condition between the genders. Steatosis was more prevalent in the male subcohort, but female patients revealed greater within-group differences.

CONCLUSIONS

Many differences were found not only in the total cohort but also between the gender subcohorts, both in the presence and absence of steatosis. We can conclude that the pathophysiological, genetic, and hormonal patterns affecting these patients delineate different individual profiles.

Very Low-Calorie Ketogenic Diet (VLCKD) as Pre-Operative First-Line Dietary Therapy in Patients with Obesity Who Are Candidates for Bariatric Surgery

Bariatric surgery is currently the most effective method for achieving long-term weight loss and reducing the risk of comorbidities and mortality in individuals with severe obesity. The pre-operative diet is an important factor in determining patients' suitability for surgery, as well as their post-operative outcomes and success in achieving weight loss. Therefore, the nutritional management of bariatric patients requires specialized expertise. Very low-calorie diets and intragastric balloon placement have already been studied and shown to be effective in promoting pre-operative weight loss. In addition, the very low-calorie ketogenic diet has a well-established role in the treatment of obesity and type 2 diabetes mellitus, but its potential role as a pre-operative dietary treatment prior to bariatric surgery has received less attention. Thus, this article will provide a brief overview of the current evidence on the very low-calorie ketogenic diet as a pre-operative dietary treatment in patients with obesity who are candidates for bariatric surgery.

Clinical Impact of Enteral Protein Nutritional Therapy on Patients with Obesity Scheduled for Bariatric Surgery: A Focus on Safety, Efficacy, and Pathophysiological Changes

BACKGROUND

Ketogenic diet-induced weight loss before bariatric surgery (BS) has beneficial effects on the reduction in the liver volume, metabolic profile, and intra- and post-operative complications. However, these beneficial effects can be limited by poor dietary adherence. A potential solution in patients showing a poor adherence in following the prescribed diet could be represented by enteral nutrition strategies. To date, no studies describe the protocol to use for the efficacy and the safety of pre-operative enteral ketogenic nutrition-based dietary protocols in terms of weight reduction, metabolic efficacy, and safety in patients with obesity scheduled for BS.

AIMS AND SCOPE

To assess the clinical impact, efficacy, and safety of ketogenic nutrition enteral protein (NEP) vs. nutritional enteral hypocaloric (NEI) protocols on patients with obesity candidate to BS.

PATIENTS AND METHODS

31 NEP were compared to 29 NEI patients through a 1:1 randomization. The body weight (BW), body mass index (BMI), waist circumference (WC), hip circumference (HC), and neck circumference (NC) were assessed at the baseline and at the 4-week follow-up. Furthermore, clinical parameters were assessed by blood tests, and patients were asked daily to report any side effects, using a self-administered questionnaire.

RESULTS

Compared to the baseline, the BW, BMI, WC, HC, and NC were significantly reduced in both groups studied (p < 0.001). However, we did not find any significative difference between the NEP and NEI groups in terms of weight loss (p = 0.559), BMI (p= 0.383), WC (p = 0.779), and HC (p = 0.559), while a statistically significant difference was found in terms of the NC (NEP, -7.1% vs. NEI, -4%, p = 0.011). Furthermore, we found a significant amelioration of the general clinical status in both groups. However, a statistically significant difference was found in terms of glycemia (NEP, -16% vs. NEI, -8.5%, p < 0.001), insulin (NEP, -49.6% vs. NEI, -17.8%, p < 0.0028), HOMA index (NEP, -57.7% vs. NEI, -24.9%, p < 0.001), total cholesterol (NEP, -24.3% vs. NEI, -2.8%, p < 0.001), low-density lipoprotein (NEP, -30.9% vs. NEI, 1.96%, p < 0.001), apolipoprotein A1 (NEP, -24.2% vs. NEI, -7%, p < 0.001), and apolipoprotein B (NEP, -23.1% vs. NEI, -2.3%, p < 0.001), whereas we did not find any significative difference between the NEP and NEI groups in terms of aortomesenteric fat thickness (p = 0.332), triglyceride levels (p = 0.534), degree of steatosis (p = 0.616), and left hepatic lobe volume (p = 0.264). Furthermore, the NEP and NEI treatments were well tolerated, and no major side effects were registered.

CONCLUSIONS

Enteral feeding is an effective and safe treatment before BS, with NEP leading to better clinical results than NEI on the glycemic and lipid profiles. Further and larger randomized clinical trials are needed to confirm these preliminary data.

Ketogenic Diet Increases Serum and White Adipose Tissue SIRT1 Expression in Mice

Overnutrition and its sequelae have become a global concern due to the increasing incidence of obesity and insulin resistance. A ketogenic diet (KD) is widely used as a dietary treatment for metabolic disorders. Sirtuin1 (SIRT1), a metabolic sensor which regulates fat homeostasis, is modulated by dietary interventions. However, the influence of nutritional ketosis on SIRT1 is still debated. We examined the effect of KD on adipose tissue, liver, and serum levels of SIRT1 in mice. Adult C57BL/6J male mice were randomly assigned to two isocaloric dietary groups and fed with either high-fat KD or normal chow (NC) for 4 weeks. Serum SIRT1, beta-hydroxybutyrate (βHB), glucose, and triglyceride levels, as well as SIRT1 expression in visceral (VAT), subcutaneous (SAT), and brown (BAT) adipose tissues, and in the liver, were measured. KD-fed mice showed an increase in serum βHB in parallel with serum SIRT1 (r = 0.732, p = 0.0156), and increased SIRT1 protein expression in SAT and VAT. SIRT1 levels remained unchanged in BAT and in the liver, which developed steatosis. Normal glycemia and triglycerides were observed. Under a KD, serum and white fat phenotypes show higher SIRT1, suggesting that one of the molecular mechanisms underlying a KD's potential benefits on metabolic health involves a synergistic interaction with SIRT1.

Management of non-alcoholic fatty liver disease patients with sleep apnea syndrome

Nonalcoholic fatty liver disease (NAFLD) is strongly associated with sleep apnea syndrome (SAS). Many NAFLD patients have SAS, and obstructive sleep apnea hypopnea syndrome is also considered to be an independent risk factor for NAFLD, as it contributes to the progression of NAFLD via oxidative stress, lipid peroxidation, inflammation, and insulin resistance. This review aims to provide some recommendations for the management of NAFLD patients with SAS, including diet, exercise, weight loss, and continuous positive airway pressure. This review also highlights the importance of effective strategies in NAFLD prevention and treatment.

Ketogenic Diet for Preoperative Weight Reduction in Bariatric Surgery: A Narrative Review

Bariatric surgery (BS) is the most effective treatment in reducing weight and the burden of comorbidities in patients with severe obesity. Despite the overall low mortality rate, intra- and post-operative complications remains quite common. Weight loss before BS reduces surgical risk, but studies are inconclusive regarding which is the best approach to apply. In this review, we summarize the current evidence on the effect of a ketogenic diet (KD) before BS. All studies agree that KD leads to considerable weight loss and important improvements in terms of surgical risk, but populations, interventions and outcomes are very heterogeneous. KD appears to be a safe and effective approach to induce weight loss before BS. However, randomized controlled trials with better-defined dietary protocols and homogeneous outcomes are necessary in order to draw firm conclusions.

Ketone Bodies and SIRT1, Synergic Epigenetic Regulators for Metabolic Health: A Narrative Review

Ketone bodies (KBs) and Sirtuin-1 (SIRT1) have received increasing attention over the past two decades given their pivotal function in a variety of biological contexts, including transcriptional regulation, cell cycle progression, inflammation, metabolism, neurological and cardiovascular physiology, and cancer. As a consequence, the modulation of KBs and SIRT1 is considered a promising therapeutic option for many diseases. The direct regulation of gene expression can occur in vivo through histone modifications mediated by both SIRT1 and KBs during fasting or low-carbohydrate diets, and dietary metabolites may contribute to epigenetic regulation, leading to greater genomic plasticity. In this review, we provide an updated overview of the epigenetic interactions between KBs and SIRT1, with a particular glance at their central, synergistic roles for metabolic health.

Very Low-Calorie Ketogenic Diet: A Potential Application in the Treatment of Hypercortisolism Comorbidities

A very low-calorie ketogenic diet (VLCKD) is characterized by low daily caloric intake (less than 800 kcal/day), low carbohydrate intake (<50 g/day) and normoproteic (1−1.5 g of protein/kg of ideal body weight) contents. It induces a significant weight loss and an improvement in lipid parameters, blood pressure, glycaemic indices and insulin sensitivity in patients with obesity and type 2 diabetes mellitus. Cushing’s syndrome (CS) is characterized by an endogenous or exogenous excess of glucocorticoids and shows many comorbidities including cardiovascular disease, obesity, type 2 diabetes mellitus and lipid disorders. The aim of this speculative review is to provide an overview on nutrition in hypercortisolism and analyse the potential use of a VLCKD for the treatment of CS comorbidities, analysing the molecular mechanisms of ketogenesis.

Impact of SARS-CoV-2 Lockdown on the Preoperative Care Program of Patients Scheduled for Bariatric Surgery

Objectives: To evaluate the effect of the SARS-CoV-2 lockdown on dietary habits, body weight, left hepatic lobe volume, use of micronutrient supplements, micronutrient status, frequency of physical activity, and evolution of comorbidities in patients undergoing preoperative care for BS. Materials and Methods: We prospectively evaluated the dietary habits (including use of micronutrient supplements and frequency of physical activity) of 36 patients who were candidates for BS from March to May 2020; 7-day food dietary records, body weight, left hepatic lobe volume by ultrasound, micronutrient status, and evolution of comorbidities were assessed. Results: All patients completed the study. Of the participants, 44.4% (16/36), 47.2% (17/36), and 27.8% (10/36) followed the preoperative indications for vegetables, fruits, and legumes, respectively, whereas over 50% did not. Furthermore, 30.6% (11/36) and 55.6% (20/36) of participants followed the prescribed recommendations for carbohydrates/sweets products and alcohol, respectively. A total of 61.1% (22/36) of participants experienced new foods and new culinary preparations. In addition, at the time of the study, we found that only 11.1% (4/36) were engaged in prescribed physical activity and only 36.1% (13/36) were taking prescribed micronutrient supplements. Compared to the initial weight, we observed an increased body weight and body mass index (+4.9%, p = 0.115; +1.89%, p = 0.0692, respectively), and no improvement in left hepatic lobe volume, micronutrient status, or comorbidities was recorded for any patient in the anamnesis. Conclusions: Lockdown determined by the SARS-CoV-2 pandemic has negatively affected the preoperative program of BS candidates, resulting in a postponement to the resumption of bariatric surgical activity.