Intermittent fasting combined with calorie restriction is effective for weight loss and cardio-protection in obese women

Distinct biophysiological effects of Ramadan fasting and traditional intermittent fasting on markers of body fat storage. A real-life study

BACKGROUND

Ramadan Intermittent fasting (RIF) exerts beneficial metabolic effects and improves gastrointestinal motility. However, a comparison between RIF and the traditional 16-hours intermittent fasting (16IF), a strategy for weight loss, is lacking.

METHODS

A total of 34 subjects (median age 32.5 years, range 18-63 years; median BMI 24.5 Kg m-1², range 18.6-37.6 Kg m-1²) were assigned to RIF (N = 18) or 16IF (N = 16) for 30 days. We measured variations in anthropometric measures (BMI, waist, and abdominal circumference), serum insulin, glucose, cortisol, non-esterified fatty acid (NEFA), body fat composition (bioelectrical impedance analysis), and the ultrasonographic measurements of liver steatosis (Hepatorenal index, HRI) and thickness of subcutaneous (SAT) and visceral (VAT) fats.

RESULTS

At baseline, BMI, rates of liver steatosis and distribution of normal weight, overweight, and obese subjects were comparable between the two groups. Body weight significantly decreased at the end of fasting in both RIF (-4.2 % vs baseline, P = 0.002) and 16IF (-2.1 % vs baseline, P = 0.002). Waist and abdominal circumferences significantly decreased only in RIF as well as the amount of body fat. In subjects with liver steatosis, SAT and VAT significantly decreased following RIF, but not 16h-IF, as well as the ultrasonographic HRI.

CONCLUSION

Both 16IF and RIF are able, during 1-month, to reduce body weight. However, RIF but not 16IF also generates marked beneficial effects in terms of reduced subcutaneous fat and liver steatosis. Further studies urge to verify the effects of different models of IF in weight-cycling and long-term management of obesity and related dysmetabolic conditions, such as ectopic fat over-storage.

Sex-specific effects of intermittent fasting on hippocampal neurogenesis via the gut-brain axis

Intermittent fasting (IF) is a widely used dietary strategy that has shown several advantageous impacts on general health and aging. IF has recently been linked to the control of neurogenesis, a crucial process for emotional control, memory, and learning, in the hippocampus. Nevertheless, there is little knowledge about the sex-specific impacts of IF on hippocampal neurogenesis and the related mechanisms, which were investigated in this study among both male and female rats, together with analyzing the involvement of the flora-gut-brain axis in facilitating these effects. Our findings show that IF favorably affects hippocampus neurogenesis in female mice relative to male mice, suggesting a sex-specific mechanism. In addition, IF influenced the diversity of the gut microbiota and decreased the synthesis of fructose-1-phosphate (F-1-P), which is believed together with fructose metabolism to be linked to neurological damage and cognitive decline. Collectively, these data indicate that the connection between the flora-gut-brain axis and hippocampus neurogenesis is significant.

Effects of Time-Restricted Eating on Aerobic Capacity, Body Composition, and Markers of Metabolic Health in Healthy Male Recreational Runners: A Randomized Crossover Trial

BACKGROUND

Optimal nutrition is highly valuable for athletes aiming at maintaining or improving body composition and sports performance. When combined with structured exercise, time-restricted energy intake may represent an effective nonpharmacological approach to achieving these results.

OBJECTIVE

The aim of this study was to investigate the effects of 4 weeks of time-restricted eating (TRE) vs 4 weeks of habitual diet on aerobic capacity, body composition, and metabolic health in 18- to 30-year-old men accustomed to endurance running.

DESIGN

This trial used a randomized-crossover study design. Participants completed graded exercise tests, body composition scans, and fasting blood samples before and after each intervention condition.

PARTICIPANTS/SETTING

Sixteen male physical education students were recruited and enrolled in the study from the Faculty of Human Kinetics-University of Lisbon in September 2020, in Lisbon, Portugal. One participant was excluded after 1 week because of a lack of adherence to the study protocol. Therefore, 15 participants completed the study and were involved in the final analysis.

INTERVENTION

During the TRE condition, participants consumed two to three meals within an 8-hour eating window (between 1:00 and 9:00 pm). Only water, tea, and coffee (without caloric additives) were permitted to be consumed in the remaining 16 hours per 24-hour period. During the non-TRE condition, participants consumed their habitual diet without any timing restrictions. The order of the TRE intervention and the habitual diet condition was randomized and counterbalanced, and participants served as their own controls. The participants followed a structured training routine during each dietary condition.

MAIN OUTCOME MEASURES

Body composition variables, indices of running aerobic capacity, and markers of metabolic health were assessed.

STATISTICAL ANALYSES PERFORMED

One-way repeated-measures analysis of variance and covariance were performed to analyze differences between conditions and time with each intervention.

RESULTS

Neither condition elicited observed changes in total body mass, fat mass, or fat-free mass between time points. Moreover, no significant changes were observed for markers of metabolic health. Significant improvements were obtained with both conditions for the first ventilatory threshold, maximum oxygen uptake (VO2max), and velocity at VO2max (P < 0.05).

CONCLUSIONS

Four weeks of endurance running and TRE, compared with 4 weeks of endurance running and a habitual diet, in healthy trained 18- to 30-year-old male recreational runners did not result in observed differences in total body mass, fat mass, or fat-free mass. In addition, TRE did not offer any additional benefit for improving submaximal or peak exercise capacity in this population.

Risks and Benefits of Intermittent Fasting for the Aging Cardiovascular System

Population aging and the associated increase in cardiovascular disease rates pose serious threats to global public health. Different forms of fasting have become an increasingly attractive strategy to directly address aging and potentially limit or delay the onset of cardiovascular diseases. A growing number of experimental studies and clinical trials indicate that the amount and timing of food intake as well as the daily time window during which food is consumed, are crucial determinants of cardiovascular health. Indeed, intermittent fasting counteracts the molecular hallmarks of cardiovascular aging and promotes different aspects of cardiometabolic health, including blood pressure and glycemic control, as well as body weight reduction. In this report, we summarize current evidence from randomized clinical trials of intermittent fasting on body weight and composition as well as cardiovascular and metabolic risk factors. Moreover, we critically discuss the preventive and therapeutic potential of intermittent fasting, but also possible detrimental effects in the context of cardiovascular aging and related disease. We delve into the physiological mechanisms through which intermittent fasting might improve cardiovascular health, and raise important factors to consider in the design of clinical trials on the efficacy of intermittent fasting to reduce major adverse cardiovascular events among aged individuals at high risk of cardiovascular disease. We conclude that despite growing evidence and interest among the lay and scientific communities in the cardiovascular health-improving effects of intermittent fasting, further research efforts and appropriate caution are warranted before broadly implementing intermittent fasting regimens, especially in elderly persons.

The Effects of Different Dietary Patterns on Bone Health

Bone metabolism is a process in which osteoclasts continuously clear old bone and osteoblasts form osteoid and mineralization within basic multicellular units, which are in a dynamic balance. The process of bone metabolism is affected by many factors, including diet. Reasonable dietary patterns play a vital role in the prevention and treatment of bone-related diseases. In recent years, dietary patterns have changed dramatically. With the continuous improvement in the quality of life, high amounts of sugar, fat and protein have become a part of people's daily diets. However, people have gradually realized the importance of a healthy diet, intermittent fasting, calorie restriction, a vegetarian diet, and moderate exercise. Although these dietary patterns have traditionally been considered healthy, their true impact on bone health are still unclear. Studies have found that caloric restriction and a vegetarian diet can reduce bone mass, the negative impact of a high-sugar and high-fat dietary (HSFD) pattern on bone health is far greater than the positive impact of the mechanical load, and the relationship between a high-protein diet (HPD) and bone health remains controversial. Calcium, vitamin D, and dairy products play an important role in preventing bone loss. In this article, we further explore the relationship between different dietary patterns and bone health, and provide a reference for how to choose the appropriate dietary pattern in the future and for how to prevent bone loss caused by long-term poor dietary patterns in children, adolescents, and the elderly. In addition, this review provides dietary references for the clinical treatment of bone-related diseases and suggests that health policy makers should consider dietary measures to prevent and treat bone loss.

Scoping review: Exploring the relationship between chrononutrition and glycemic responses in the adult population

Chrononutrition, an emerging body of evidence on the relationship between biological rhythms and metabolism, has been established to be associated with glycemic responses. However, the available evidence is inconsistent, due to protocol variations. Therefore, this review aims to summarize the findings on chrononutrition characteristics and their association with glycemic responses among adults. Systematic searches were conducted across six databases (PubMed, EBSCO Host, ProQuest Central, MEDLINE & Ovid, Scopus and Web of Science) to identify all relevant studies published from January 2012. Two reviewers independently screened the abstracts and full-text articles based on the inclusion and exclusion criteria. Details about population characteristics, study methods and key findings were extracted following the PRISMA-ScR guideline. The quality of selected studies was evaluated using the mixed methods appraisal tool. The searchers identified 49 studies eligible for analysis. The results showed that meal timing, particularly night-time eating and snacking were associated with glycemic responses. Regarding meal regularity, skipping breakfast may affect glycemic responses, but no clear conclusion was drawn about its effect on insulin. The association between meal frequency and glycemic responses was inconclusive. Night fasting duration and restricted eating window are potentially associated with glycemic responses. The current review extensively investigates the association between chrononutrition factors and glycemic responses in adults. However, more prospective cohort and interventional studies are needed to better understand this causal-effect relationship.

Intermittent fasting as a dietary intervention with potential sexually dimorphic health benefits

Intermittent fasting (IF) has proven to be a feasible dietary intervention for the wider population. The recent increase in IF clinical trials highlights its potential effects on health, including changes in body composition, cardiometabolic status, and aging. Although IF may have clinical applications in different populations, studies suggest there may be sex-specific responses in parameters such as body composition or glucose and lipid metabolism. Here, the existing literature on IF clinical trials is summarized, the application of IF in both disease prevention and management is discussed, and potential disparities in response to this type of diet between men and women are assessed. Moreover, the potential mechanisms that may be contributing to the sexually dimorphic response, such as age, body composition, tissue distribution, or sex hormones are investigated. This review underscores the need to further study these sex-specific responses to IF to define the most effective time frames and length of fasting periods for men and women. Tailoring IF to specific populations with a personalized approach may help achieve its full potential as a lifestyle intervention with clinical benefits.

Alternate-day fasting ameliorated anxiety-like behavior in high-fat diet-induced obese mice

Alternate-day fasting (ADF) has been reported to reduce body weight, neuroinflammation, and oxidative stress damage. However, it is not known whether ADF affects obesity-induced anxiety-like behavior. Here, male C57BL/6 mice were given an alternate fasting and high-fat diet (HFD) or standard chow diet (SD) every other day for 16 or 5 weeks. After the intervention, the degree of anxiety of the mice was evaluated by the open field test (OFT) and the elevated plus maze (EPM) test. Pathological changes in the hippocampus, the expression of Sirt1 and its downstream protein monoamine oxidase A (MAO-A) in the hippocampus, and the expression of 5-hydroxytryptamine (5-HT) were detected. Compared with HFD-fed mice, HFD-fed mice subjected to ADF for 16 weeks had a lower body weight but more brown adipose tissue (BAT), less anxiety behavior, and less pathological damage in the hippocampus, and lower expression of Sirt1 and MAO-A protein and higher 5-HT levels in the hippocampus could be observed. In addition, we noted that long-term ADF intervention could cause anxiety-like behavior in SD mice. Next, we changed the intervention time to 5 weeks. The results showed that short-term ADF intervention could reduce the body weight and increase the BAT mass of SD mice, but it did not affect anxiety. These results indicated that long-term ADF ameliorated obesity-induced anxiety-like behavior and hippocampal damage, but caused anxiety in normal-weight mice. Short-term ADF did not produce adverse emotional reactions in normal-weight mice. Here, we might provide new ideas for the treatment of obesity-induced anxiety.

Promotion of Successful Weight Management in Overweight and Obese Veterans (POWER-VET): Trial Design and Methods

BACKGROUND

Almost 75% of US adults are overweight or obese. Though intentional weight loss of as little as 3% improves physical functioning and reduces cardiometabolic risk, most adults are unsuccessful at long-term weight maintenance. Our hypothesis is that intermittent fasting (IF: short periods of intense energy restriction) will reduce weight regain. IF may combat obesity due to its effects on nutrient-sensing signaling pathways and circadian rhythm. The objective of this randomized clinical trial is to test the effectiveness of an intensive body weight management program with and without IF.

METHODS

In the Promotion of Successful Weight Management in Overweight and Obese Veterans (POWER-VET) trial (NCT04131647), 154 middle-aged and older adults (50-75 years) who are overweight and obese (BMI: 25-40 kg/m2) and seen at either a Baltimore, MD or San Antonio, TX Veterans Affairs Medical Center will be enrolled. Participants will undergo 12 weeks of weight loss (including a low-calorie heart healthy (HH) diet and exercise). Following weight loss, participants will be randomly assigned to one of two 24-week weight maintenance (WM) interventions: WM alone (continuation of HH diet and exercise) or WM + IF. The primary aim is to determine the effect of WM + IF compared to WM alone on body weight maintenance after intentional weight loss.

DISCUSSION

Determining effective, translatable strategies that minimize weight regain following successful weight loss holds public health relevance. This POWER-VET trial introduces an innovative practice of IF to prevent weight regain after clinically significant weight reduction and could provide evidence-based recommendations to promote this type of intervention in middle aged and older adults.

Unlocking the Benefits of Fasting: A Review of its Impact on Various Biological Systems and Human Health

Fasting has gained significant attention in recent years for its potential health benefits in various body systems. This review aims to comprehensively examine the effects of fasting on human health, specifically focusing on its impact on different body's physiological systems. The cardiovascular system plays a vital role in maintaining overall health, and fasting has shown promising effects in improving cardiovascular health markers such as blood pressure, cholesterol levels, and triglyceride levels. Additionally, fasting has been suggested to enhance insulin sensitivity, promote weight loss, and improve metabolic health, thus offering potential benefits to individuals with diabetes and metabolic disorders. Furthermore, fasting can boost immune function, reduce inflammation, enhance autophagy, and support the body's defense against infections, cancer, and autoimmune diseases. Fasting has also demonstrated a positive effect on the brain and nervous system. It has been associated with neuroprotective properties, improving cognitive function, and reducing the risk of neurodegenerative diseases, besides the ability of increasing the lifespan. Hence, understanding the potential advantages of fasting can provide valuable insights for individuals and healthcare professionals alike in promoting health and wellbeing. The data presented here may have significant implications for the development of therapeutic approaches and interventions using fasting as a potential preventive and therapeutic strategy.

Role of insulin resistance and leptin in the effect of intermittent feeding with a high-protein ketogenic diet on body composition in rats

OBJECTIVES

The prevalence of obesity and overweight in children has been increasing rapidly worldwide and threatens society with various chronic diseases that these children are born with. High-protein ketogenic diets and intermittent nutrition are thought to be protective against obesity and metabolic syndrome MetS. However, the exact effects and results, insulin resistance, and the role of leptin in the functioning mechanism of these diets have not been fully elucidated. The aim of this study was to investigate the roles of insulin resistance and leptin hormone on the effects of body composition with a high-protein ketogenic diet and intermittent nutrition combination.

METHODS

Thirty-two young non-obese rats were randomly divided into four equal groups. Both the standard diet and the high-protein ketogenic diet were given ad libitum and intermittently to the rats for 6 wk. The body weight and fat mass of the rats were measured at the end of the experiment. The fasting glucose, leptin, insulin, high- and low-density lipoprotein, and triacylglycerols were measured with the blood samples.

RESULTS

The lowest body weight was observed in the intermittent and high-protein ketogenic diet group, followed by the free high-protein ketogenic diet and standard intermittent diet group, respectively. Also, the lowest body fat mass was observed in the intermittent and high-protein ketogenic diet group, followed by the standard intermittent diet group. Although there was no change in leptin, insulin, high- and low-density lipoprotein, and triacylglycerol levels in any group, the lowest blood glucose rate was observed in the intermittent and high-protein ketogenic diet group.

CONCLUSION

The results of the present study revealed that an intermittent high-protein ketogenic diet is more effective than others in weight loss without disrupting biochemical health parameters, and the applied diets do not prevent growth and development.

The Effect of Month-Long Daily Fasting on Semen Parameters: A Retrospective Cohort Study

OBJECTIVE

The aim of the study was to determine whether Ramadan month-long daily fasting affects semen analysis parameters.

METHODS

This retrospective cohort study was conducted in tertiary academic medical center. Medical records of 97 Muslim patients who were admitted to the IVF unit from May 2011 to May 2021 were reviewed. Only men who provided at least one semen sample during Ramadan period (Ramadan month +70 days after) and one sample not during Ramadan were included. Semen characteristics of each patient were independently compared to themselves.

RESULTS

The post-gradient semen analysis indicated significantly lower progressive sperm motility (mean 30.01 ± 20.46 vs. 38.12 ± 25.13) (p < 0.001). The decrease in the progressive motility remained significant among patients with non-male factor indications (p < 0.001). In the non-male factor indication group, the difference in the progressive motility of the post-gradient semen analysis between the 2 samples was not statistically significant (p = 0.4). There were no significant differences between semen parameters before centrifuging. The incidence of asthenospermia (progressive sperm motility <32%) as an absolute parameter was higher after centrifuging the semen sample during the Ramadan period (p = 0.04).

CONCLUSIONS

Semen samples collected during Ramadan period were associated with lower progressive motility and reduced semen volume compared to semen samples from the same men outside of the Ramadan period. A possible effect of these altered semen parameters on fertility should be investigated further.

Intermittent fasting in health and disease

CONTEXT

Intermittent fasting, a new-age dietary concept derived from an age-old tradition, involves repetitive cycles of fasting/calorie restriction and eating.

OBJECTIVE

We aim to take a deep dive into the biological responses to intermittent fasting, delineate the disease-modifying and cognitive effects of intermittent fasting, and also shed light on the possible side effects.

METHODS

Numerous in vitro and in vivo studies were reviewed, followed by an in-depth analysis, and compilation of their implications in health and disease.

RESULTS

Intermittent fasting improves the body's stress tolerance, which is further amplified with exercise. It impacts various pathological conditions like cancer, obesity, diabetes, cardiovascular disease, and neurodegenerative diseases.

CONCLUSION

During dietary restriction, the human body experiences a metabolic switch due to the depletion of liver glycogen, which promotes a shift towards utilising fatty acids and ketones in the system, thereby significantly impacting adiposity, ageing and the immune response to various diseases.

Fasting: From Physiology to Pathology

Overnutrition is a risk factor for various human diseases, including neurodegenerative diseases, metabolic disorders, and cancers. Therefore, targeting overnutrition represents a simple but attractive strategy for the treatment of these increasing public health threats. Fasting as a dietary intervention for combating overnutrition has been extensively studied. Fasting has been practiced for millennia, but only recently have its roles in the molecular clock, gut microbiome, and tissue homeostasis and function emerged. Fasting can slow aging in most species and protect against various human diseases, including neurodegenerative diseases, metabolic disorders, and cancers. These centuried and unfading adventures and explorations suggest that fasting has the potential to delay aging and help prevent and treat diseases while minimizing side effects caused by chronic dietary interventions. In this review, recent animal and human studies concerning the role and underlying mechanism of fasting in physiology and pathology are summarized, the therapeutic potential of fasting is highlighted, and the combination of pharmacological intervention and fasting is discussed as a new treatment regimen for human diseases.

Effects of Different Fasting Interventions on Cardiac Autonomic Modulation in Healthy Individuals: A Secondary Outcome Analysis of the EDIF Trial

The impact of a fasting intervention on electrocardiographic (ECG) time intervals and heart rate variability (HRV) is a focus that is scarcely analyzed. The main focus of these secondary outcome data was to describe the impact of a different fasting intervention on ECG and HRV analyses. Twenty-seven healthy individuals participated in this study (11 females, aged 26.3 ± 3.8 years, BMI 24.7 ± 3.4 kg/m2), including a pre-intervention controlled run-in period. Participants were randomized to one of the three fasting cohorts: (I) alternate day fasting (ADF, n = 8), (II) 16/8 fasting (16/8 h of fasting/feasting, n = 11) and (III) 20/4 fasting (20/4 h of fasting/feasting, n = 8). An analysis of baseline ECG parameters and HRV parameters following different fasting interventions demonstrated the safety of these interventions without impacting on heart rate variability parameters during Schellong-1 testing, and revealed comparable preserved autonomic cardiac modulation (ACM) independently of the fasting intervention. In conclusion, different short-term fasting interventions demonstrated no safety ECG-based concerns and showed comparable ACM based on ECG and HRV assessments. Finally, our research topic might strengthen the scientific knowledge of intermittent fasting strategies and indicate potential clinically preventive approaches with respect to occurring metabolic disease and obesity in healthy young subjects.

The Health-Promoting Effects and the Mechanism of Intermittent Fasting

Intermittent fasting (IF) is an eating pattern in which individuals go extended periods with little or no energy intake after consuming regular food in intervening periods. IF has several health-promoting effects. It can effectively reduce weight, fasting insulin levels, and blood glucose levels. It can also increase the antitumor activity of medicines and cause improvement in the case of neurological diseases, such as memory deficit, to achieve enhanced metabolic function and prolonged longevity. Additionally, IF activates several biological pathways to induce autophagy, encourages cell renewal, prevents cancer cells from multiplying and spreading, and delays senescence. However, IF has specific adverse effects and limitations when it comes to people of a particular age and gender. Hence, a more systematic study on the health-promoting effects and safety of IF is needed. This article reviewed the research on the health-promoting effects of IF, providing a theoretical basis, direction for subsequent basic research, and information related to the clinical application of IF.

Ageing, Metabolic Dysfunction, and the Therapeutic Role of Antioxidants

The gradual ageing of the world population has been accompanied by a dramatic increase in the prevalence of obesity and metabolic diseases, especially type 2 diabetes. The adipose tissue dysfunction associated with ageing and obesity shares many common physiological features, including increased oxidative stress and inflammation. Understanding the mechanisms responsible for adipose tissue dysfunction in obesity may help elucidate the processes that contribute to the metabolic disturbances that occur with ageing. This, in turn, may help identify therapeutic targets for the treatment of obesity and age-related metabolic disorders. Because oxidative stress plays a critical role in these pathological processes, antioxidant dietary interventions could be of therapeutic value for the prevention and/or treatment of age-related diseases and obesity and their complications. In this chapter, we review the molecular and cellular mechanisms by which obesity predisposes individuals to accelerated ageing. Additionally, we critically review the potential of antioxidant dietary interventions to counteract obesity and ageing.

Protective effects of calorie restriction and 17-β estradiol on cardiac hypertrophy in ovariectomized obese rats

Obesity and menopause lead to cardiovascular diseases. Calorie restriction (CR) can modulate estrogen deficiency and obesity-related cardiovascular diseases. The protective effects of CR and estradiol on cardiac hypertrophy in ovariectomized obese rats were explored in this study. The adult female Wistar rats were divided into sham and ovariectomized (OVX) groups that received a high-fat diet (60% HFD) or standard diet (SD) or 30% CR for 16 weeks, and then, 1mg/kg E2 (17-β estradiol) was injected intraperitoneally every 4 days for four weeks in OVX-rats. Hemodynamic parameters were evaluated before and after each diet. Heart tissues were collected for biochemical, histological, and molecular analysis. HFD consumption led to weight gain in sham and OVX rats. In contrast, CR and E2 led to body weight loss in these animals. Also, heart weight (HW), heart weight/body weight (HW/BW) ratio, and left ventricular weight (LVW) were enhanced in OVX rats that received SD and HFD. E2 reduced these indexes in both diet conditions but reduction effects of CR were seen only in HFD groups. HFD and SD feeding increased hemodynamic parameters, ANP (atrial natriuretic peptide) mRNA expression, and TGF-β1(transforming growth factor-beta 1) protein level in the OVX animals, while CR and E2 reduced these factors. Cardiomyocyte diameter and hydroxyproline content were increased in the OVX-HFD groups. Nevertheless, CR and E2 decreased these indicators. The results showed that CR and E2 treatment reduced obesity-induced-cardiac hypertrophy in ovariectomized groups (20% and 24% respectively). CR appears to have almost as reducing effects as estrogen therapy on cardiac hypertrophy. The findings suggest that CR can be considered a therapeutic candidate for postmenopausal cardiovascular disease.

The Role of Intermittent Fasting in the Management of Nonalcoholic Fatty Liver Disease: A Narrative Review

Intermittent fasting is a non-pharmacological dietary approach to management of obesity and metabolic syndrome, involving periodic intervals of complete or near-complete abstinence from food and energy-containing fluids. This dietary strategy has recently gained significant popularity in mainstream culture and has been shown to induce weight loss in humans, reduce gut and systemic inflammation, and improve gut microbial diversity and dysbiosis (largely in animal models). It has been hypothesized that intermittent fasting could be beneficial in the management of nonalcoholic fatty liver disease, given the condition's association with obesity. This review summarizes protocols, potential mechanisms of action, and evidence for intermittent fasting in nonalcoholic fatty liver disease. It also highlights practical considerations for implementing intermittent fasting in clinical practice. A search of the literature for English-language articles related to intermittent fasting or time-restricted feeding and liver disease was completed in PubMed and Google Scholar. Potential mechanisms of action for effects of intermittent fasting included modulation of circadian rhythm, adipose tissue and adipokines, gut microbiome, and autophagy. Preclinical, epidemiological, and clinical trial data suggested clinical benefits of intermittent fasting on metabolic and inflammatory markers in humans. However, there was a paucity of evidence of its effects in patients with nonalcoholic fatty liver disease. More clinical studies are needed to determine mechanisms of action and to evaluate safety and efficacy of intermittent fasting in this population.

Effect of Medically Supervised Prolonged Fasting Therapy on Vitamin D, B12, Body Weight, Body Mass Index, Vitality and Quality of Life: A Randomized Control Trial

Background

Recent research indicates prolonged fasting for more than 7 days is beneficial in priming the vitamin D metabolism. However, methodological limitations in previous studies, such as insufficient sample size and a lack of control group, limits its generalizability. The present study evaluated the impact of prolonged fasting (10 days) on vitamin D, vitamin B12, body mass index (BMI), weight, hemoglobin, vitality and quality of life (QoL) compared to a normal diet.

Methods

This randomized control trial was conducted in an in-patient private yoga and naturopathy setting between February and April 2022. A total of 52 participants (mean age 51.57 ± 13.67 years) with varying medical conditions were randomized into a fasting group (FG) or a normal diet group (NDG) with 26 participants in each group. The FG was on a fasting diet (500 kCal/day) which included holy basil herbal tea, lemon honey water, and water (3 L). The NDG (1500 kCal/day) consumed a routine diet that included Indian bread, pulses, steamed rice, vegetable salads, and beverages.

Results

The FG has shown significant increase in the Vitamin D levels (P = .003, d = 0.475), vitality (P = .006, d = 0.425), physical QoL (P < .001, d = 0.549), psychological QoL (P = .002, d = 0.488), and environmental QoL (P = .004, d = 0.457) compared to NDG. No significant changes were observed in vitamin B12, weight, BMI, haemoglobin, and social QoL. A weak to moderate (ρ = 0.330-0.483) positive correlation was observed between vitality scores and QoL domains, whereas BMI scores showed an inverse correlation (ρ = -.280) with vitamin D levels.

Conclusion

The results suggest that prolonged fasting for 10 days can improve vitamin D levels, improve vitality, and promote quality of life compared to a normal diet. Unlike previous studies, the FG does not differ from the NDG concerning weight and BMI. Nevertheless, fasting may be utilized as an effective tool to tackle vitamin D deficiency and associated health insufficiencies.

Intermittent fasting two days versus one day per week, matched for total energy intake and expenditure, increases weight loss in overweight/obese men and women

Background

Intermittent fasting (IF), consisting of either a one-day (IF1) or two consecutive days (IF2) per week, is commonly used for optimal body weight loss. Our laboratory has previously shown an IF1 diet combined with 6d/week of protein pacing (P; 4–5 meals/day evenly spaced, ~ 30% protein/day) significantly enhances weight loss, body composition, and cardiometabolic health in obese men and women. Whether an IF1-P or IF2-P, matched for weekly energy intake (EI) and expenditure (EE), is superior for weight loss, body composition, and cardiometabolic health is unknown.

Methods

This randomized control study directly compared an IF1-P (n = 10) versus an IF2-P (n = 10) diet on weight loss and body composition, cardiovascular (blood pressure and lipids), hormone, and hunger responses in 20 overweight men and women during a 4-week weight loss period. Participants received weekly dietary counseling and monitoring of compliance from a registered dietitian. All outcome variables were assessed pre (week 0) and post (week 5).

Results

Both groups significantly reduced body weight, waist circumference, percent body fat, fat mass, hunger, blood pressure, lipids, glucose, and increased percent fat-free mass (p < 0.05). However, IF2-P resulted in significantly greater reductions in body weight (-29%) and waist circumference (-38%) compared to IF1-P (p < 0.05), and showed a strong tendency for greater reductions in fat mass, glucose, and hunger levels (p < 0.10) despite similar weekly total EI (IF1-P, 9058 ± 692 vs. IF2-P, 8389 ± 438 kcals/week; p = 0.90), EE (~ 300 kcals/day; p = 0.79), and hormone responses (p > 0.10).

Conclusions

These findings support short-term IF1-P and IF2-P to optimize weight loss and improve body composition, cardiometabolic health, and hunger management, with IF2-P providing enhanced benefits in overweight women and men.

Trial registration

This trial was registered March 03, 2020 at www.clinicaltrials.gov as NCT04327141.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12937-022-00790-0.

Intermittent Energy Restriction for Weight Loss: A Systematic Review of Cardiometabolic, Inflammatory and Appetite Outcomes

Current guidelines for obesity treatment recommend reducing daily caloric intake for weight loss. However, long-term weight loss continues to be an issue in obesity management. Alternative weight loss strategies have increased in popularity, such as intermittent energy restriction (IER), a type of eating pattern with periods of fasting alternating with unrestricted eating. The effects of IER on weight loss, cardiovascular risk factors, inflammation, and appetite are not clear. The purpose of this systematic review was to analyze short- (<24 weeks) and long-term (≥24 weeks) effects of IER on anthropometric, cardiometabolic, inflammatory, and appetite outcomes in adults with overweight/obesity. PubMed, CINAHL, Embase, and PsycInfo were searched from inception to July 2020. Human randomized controlled trials (RCTs) on IER with participants with a body mass index ≥25 kg/m² were included in this review. A total of 42 articles (reporting on 27 different RCTs) were included. In short-term studies, IER showed pre-to-post treatment improvements in eight of nine studies that assessed weight. Weight outcomes were sustained in the long-term. However, no significant long-term between group differences were observed in fat mass, other anthropometric, cardiometabolic, inflammatory, or appetite outcomes. Compared to continuous energy restriction (CER), IER showed no significant long-term differences in anthropometric, cardiometabolic, inflammatory, or appetite outcomes in included studies. More long-term studies are needed to assess the benefits of IER on health outcomes.

The role of nutrition in inflammaging

BACKGROUND

Old age is characterized by a peculiar low-grade, chronic, and "sterile" inflammatory state, which has been termed "inflammaging." This is believed to substantially contribute to the pathogenesis of many age-related diseases and to the progression of the ageing process. An adequate nutritional status is of great importance for maintaining proper immune system functionality and preventing frailty in the elderly.

METHODS

The purpose of this narrative review is to synthesize what is known about the interaction between inflammaging and nutrition, focusing on the role of the Mediterranean diet, gut microbiota and calorie restriction (CR) in reducing systemic inflammation and improving clinical outcomes.

CONCLUSIONS

Dietary components may affect inflammation directly, counteracting the low grade age-related inflammation. In this regard, healthy diets, including the Mediterranean diet, are associated with lower concentrations of inflammatory mediators, like C-reactive protein (CRP) and Tumor Necrosis Factor-α (TNF-α), that are hallmarks of inflammaging. Among the components of a healthy diet, a higher intake of whole grains, vegetables and fruits, nuts and fish are all associated with lower inflammation. One area of promising research is the microbiome-ageing interaction. Indeed, dysbiosis plays a role in sub-optimal metabolism, immune function and brain function and contributes to the poor health and impaired well-being associated with ageing. Modulation of the gut microbiota has shown promising results in some disorders. Additionally, the discovery of several molecular pathways associated with ageing, and the characterization of the beneficial effects of calorie restriction (CR) in modulating metabolic pathways and preventing inflammation, should encourage research on CR mimetics, drugs able to promote lifespan and extend healthspan.

Caloric restriction and Roux-en-Y Gastric Bypass promote white adipose tissue browning in mice

PURPOSE

Caloric restriction (CR) and Roux-en-Y Gastric Bypass (RYGB) are considered effective means of body weight control, but the mechanism by which CR and RYGB protect against high-fat diet (HFD)-induced obesity remains elusive. The browning of white adipose tissue (WAT) is a potential approach to combat obesity. Here we assess whether browning of WAT is involved in CR- and RYGB-treatment.

METHODS

The average size of adipocytes was determined by histological analysis. Expression of thermogenic genes in both human subjects and mice were measured by quantitative real-time PCR and immunohistochemical staining.

RESULTS

The average size of adipocytes was bigger, while the expression of thermogenic genes such as uncoupling protein 1 (UCP1), nuclear factor erythroid-2 like 1 (NRF1) and PPARγ coactivator-1 α (PGC1α) were lower in the WAT of obese subjects when compared to lean controls. Both CR and RYGB promoted weight and fat loss. Increment of the average adipocytes size and down-regulation of thermogenic genes were significantly reversed by both CR and RYGB in the WAT of obese mice.

CONCLUSIONS

Our findings showed that CR and RYGB significantly improved high-fat diet-induced lipid accumulation by promoting the browning of WAT.

Effect of Intermittent Fasting Diet on Glucose and Lipid Metabolism and Insulin Resistance in Patients with Impaired Glucose and Lipid Metabolism: A Systematic Review and Meta-Analysis

The question of whether or not intermittent fasting diets improve the clinical indicators of glycolipid metabolism remains unclear. This study systematically reviewed the relevant clinical trials to evaluate the effects of intermittent fasting diet on glucose and lipid metabolism and insulin sensitivity in patients with metabolic syndrome. To evaluate the effect of intermittent fasting diet intervention on patients with disorders of glucose and lipid metabolism, random-effect or fixed-effect meta-analysis models were used to calculate the average difference before and after intermittent fasting diet intervention and the corresponding 95% confidence intervals (CIs). After intermittent fasting diet intervention, in terms of glucose metabolism, fasting blood glucose reduced by 0.15 mmol/L (95% CI: -0.23; -0.06), glycosylated hemoglobin reduced by 0.08 (95% CIs: -0.25; -0.10), insulin plasma levels reduced by 13.25 uUI (95% CIs: -16.69; -9.82), and HOMA-IR decreased by 0.31 on an average (95% CIs: -0.44; -0.19). In addition, BMI decreased by 0.8 kg/m² (95% CIs: -1.32; -0.28), body weight reduced by 1.87 kg (95% CIs: -2.67; -1.07), and the waist circumference decreased by 2.08 cm (95% CIs: -3.06; -1.10). Analysis of lipid metabolism showed that intermittent fasting diet intervention effectively reduced the total cholesterol level by 0.32 mmol/L (95% CIs: -0.60; -0.05), low-density lipoprotein level by 0.22 mmol/L (95% CIs: -0.37; -0.07), and triglyceride level by 0.04 mmol/L (95% CIs: -0.15; -0.07). Intermittent fasting diets have certain therapeutic effects on blood glucose and lipids in patients with metabolic syndrome and significantly improve insulin resistance. It may be considered as an auxiliary treatment to prevent the occurrence and development of chronic diseases.

Dissociation between Corneal and Cardiometabolic Changes in Response to a Time-Restricted Feeding of a High Fat Diet

Mice fed a high fat diet (HFD) ab libitum show corneal dysregulation, as evidenced by decreased sensitivity and impaired wound healing. Time-restricted (TR) feeding can effectively mitigate the cardiometabolic effects of an HFD. To determine if TR feeding attenuates HFD-induced corneal dysregulation, this study evaluated 6-week-old C57BL/6 mice fed an ad libitum normal diet (ND), an ad libitum HFD, or a time-restricted (TR) HFD for 10 days. Corneal sensitivity was measured using a Cochet-Bonnet aesthesiometer. A corneal epithelial abrasion wound was created, and wound closure was monitored for 30 h. Neutrophil and platelet recruitment were assessed by immunofluorescence microscopy. TR HFD fed mice gained less weight (p < 0.0001), had less visceral fat (p = 0.015), and had reduced numbers of adipose tissue macrophages and T cells (p < 0.05) compared to ad libitum HFD fed mice. Corneal sensitivity was reduced in ad libitum HFD and TR HFD fed mice compared to ad libitum ND fed mice (p < 0.0001). Following epithelial abrasion, corneal wound closure was delayed (~6 h), and neutrophil and platelet recruitment was dysregulated similarly in ad libitum and TR HFD fed mice. TR HFD feeding appears to mitigate adipose tissue inflammation and adiposity, while the cornea remains sensitive to the pathologic effects of HFD feeding.

Safety of Every-Other-Day Fasting in the Treatment of Spinal Cord Injury: A Randomized Controlled Trial

ABSTRACT

Every-other-day fasting is effective for a variety of major human diseases, but the safety of these interventions is uncertain for patients with spinal cord injury. A randomized controlled study was conducted to investigate the safety of every-other-day fasting in patients with spinal cord injury. Participants who met the diagnostic inclusion and exclusion criteria were randomly divided into the control and every-other-day fasting groups. In the every-other-day fasting group, fasting lasted from 09:00 p.m. on day 1 to 06:00 p.m. on the following day (day 2). Dinner on day 2 was restricted to approximately 30% of the average daily calorie intake. The changes in plasma glucose were recorded daily for 2 days and every other day from the third day after every-other-day fasting intervention. The changes in albumin, prealbumin, plasma potassium, serum sodium, blood calcium, body weight, and body mass index were monitored at the baseline and at the end of the every-other-day fasting intervention. The results showed that compared with the control group, the mean blood glucose levels were significantly decreased from the second week after every-other-day fasting intervention. The body weight of patients in the every-other-day fasting group was notably reduced compared with that at baseline, whereas in body mass index, no obvious differences were observed before and after treatment with every-other-day fasting. In general, every-other-day fasting could be considered as a safe approach for individuals with spinal cord injury.

A randomised controlled trial of the 5:2 diet

Objective

The 5:2 diet is a popular intermittent energy restriction method of weight management that awaits further evaluation. We compared the effects of one-off 5:2 instructions with the effects of one-off standard multicomponent weight-management advice; and also examined whether additional behavioural support enhances 5:2 adherence and efficacy compared to one-off instructions.

Methods

Three hundred adults with obesity were randomised to receive a Standard Brief Advice (SBA) covering diet and physical activity (N = 100); 5:2 self-help instructions (5:2SH) (N = 100); or 5:2SH plus six once-weekly group support sessions (N = 100). Participants were followed up for one year.

Results

Adherence to 5:2SH was initially high (74% at 6 weeks), but it declined over time (31% at 6 months and 22% at one year). 5:2SH and SBA achieved similar weight-loss at six months (-1.8kg (SD = 3.5) vs -1.7kg (SD = 4.4); b = 0.23, 95%CI:-0.79–1.27, p = 0.7) and at one year (-1.9kg (SD = 4.9) vs -1.8kg (SD = 5.7), b = 0.20, 95%CI:-1.21–1.60, p = 0.79), with 18% vs 15% participants losing ≥5% of their body weight with 5:2SH and SBA, respectively at one year (RR = 0.83, 95%CI:0.44–1.54, p = 0.55). Both interventions received positive ratings, but 5:2SH ratings were significantly higher. 5:2SH had no negative effect on fat and fiber intake and physical activity compared to SBA. Compared to 5:2SH, 5:2G generated a greater weight loss at 6 weeks (-2.3kg vs -1.5kg; b = 0.74, 95%CI:1.37–0.11, p = 0.02), but by one year, the difference was no longer significant (-2.6kg vs -1.9kg, p = 0.37; ≥5% body weight loss 28% vs 18%, p = 0.10).

Conclusions

Simple 5:2 advice and multicomponent weight management advice generated similar modest results. The 5:2 diet did not undermine other health behaviours, and it received more favourable ratings. Adding initial group support enhanced 5:2 adherence and effects, but the impact diminished over time. Health professionals who provide brief weight management advice may consider including the 5:2 advice as an option.

Trial registration

ISRCTN registry (ISRCTN79408248).

The effects of diet on weight and metabolic outcomes in patients with double diabetes: A systematic review

With the global rise in obesity and the metabolic syndrome, double diabetes is increasingly prevalent in patients with type 1 diabetes. This review investigated the effects of diet on weight management and metabolic outcomes in patients with double diabetes. MEDLINE, CENTRAL, EMBASE, PsycINFO, CINAHL, ERIC, and Web of Science databases were searched through September 2020. Population- or individual-level dietary interventions, and observational studies investigating dietary patterns in adults with type 1 diabetes and overweight or obesity, were eligible for inclusion. The quality of studies was assessed. Four eligible studies were included in this review, comprising two randomized controlled trials, one pretest-posttest study, and one cross-sectional study. Study populations included between 10 and 1040 participants. Dietary interventions included the Mediterranean diet, low-fat diet, intermittent fasting, continuous energy restriction, and a combination of fasting and a standardized low-calorie diabetic diet (LCD). Significant weight loss was observed within groups for low-fat diet, Mediterranean diet, fasting, LCD with fasting, intermittent fasting, or continuous energy restriction, but there were no between-group differences. Weight maintenance was only achieved in interventions where fasting or intermittent fasting were present. Dietary interventions in published data failed to demonstrate effects on metabolic syndrome. Larger sample, high-quality trials conducted over longer periods are urgently required to determine the efficacy of diet for weight management and improving metabolic outcomes in individuals with double diabetes. This would provide much needed evidence-based guidance for dietary interventions, which are well known to be the cornerstone of clinical care.

The effects of intermittent fasting regimens in middle-age and older adults: Current state of evidence

Aging is associated with a host of biological changes that contribute to a progressive decline in cognitive and physical function, ultimately leading to a loss of independence and an increased risk of mortality. The unprecedented growth of the aging population has thus created an urgent need for interventions that can preserve older adults' capacity to live independently and to function well. To date, there is no conclusive evidence supporting the efficacy of an intervention to prevent or reverse physical disability in older persons at risk of functional decline. A growing body of evidence indicates that prolonged fasting periods and different types of intermittent fasting regimens can have positive effects on anthropometric and metabolic health parameters in middle-aged adults similar to that of calorie restriction. For this reason, there is increasing scientific interest in further exploring the biological and metabolic effects of intermittent fasting approaches, as well as the feasibility and safety of popular types of intermittent fasting regimens in older adults. Thus, the purpose of the present review is to describe the state of evidence of different types of intermittent fasting regimes, specifically time-restricted eating and 5:2 intermittent fasting, in the growing population of middle-aged and older adults. A small, but growing body of evidence indicates both time restricted eating (TRE) and 5:2 intermittent fasting approaches can produce modest weight loss; however, only the 5:2 approach produced clinically meaningful weight losses. Reductions in blood pressure were observed for both TRE and 5:2 fasting approaches, but the effects were not consistent across studies. The majority of studies to date, in middle-age and older adults, however, have been of short duration in small study samples. Future clinical trials with larger populations and longer intervention durations are required to better understand the risks versus benefits of different types of intermittent fasting regimens in middle-age and older individuals.

Which Diets Are Effective in Reducing Cardiovascular and Cancer Risk in Women with Obesity? An Integrative Review

Women are more affected by obesity than men which increases their risk of cancer and cardiovascular disease (CVD). Therefore, it is important to understand the effectiveness of different types of diet in the context of women's health. This review aims to summarize the scientific evidence on the effects of different types of diet for women with obesity and their impact on CVD and cancer risk. This review included epidemiological and clinical studies on adult women and different types of diets, such as the Mediterranean (MED) diet, the Traditional Brazilian Diet, the Dietary Approach to Stop Hypertension (DASH), intermittent fasting (IF), calorie (energy) restriction, food re-education, low-carbohydrate diet (LCD) and a very low-carbohydrate diet (VLCD). Our main findings showed that although LCDs, VLCD and IF are difficult to adhere to over an extended period, they can be good options for achieving improvements in body weight and cardiometabolic parameters. MED, DASH and the Traditional Brazilian Diet are based on natural foods and reduced processed foods. These diets have been associated with better women's health outcomes, including lower risk of CVD and cancer and the prevention and treatment of obesity.

The Sick Adipose Tissue: New Insights Into Defective Signaling and Crosstalk With the Myocardium

Adipose tissue (AT) biology is linked to cardiovascular health since obesity is associated with cardiovascular disease (CVD) and positively correlated with excessive visceral fat accumulation. AT signaling to myocardial cells through soluble factors known as adipokines, cardiokines, branched-chain amino acids and small molecules like microRNAs, undoubtedly influence myocardial cells and AT function via the endocrine-paracrine mechanisms of action. Unfortunately, abnormal total and visceral adiposity can alter this harmonious signaling network, resulting in tissue hypoxia and monocyte/macrophage adipose infiltration occurring alongside expanded intra-abdominal and epicardial fat depots seen in the human obese phenotype. These processes promote an abnormal adipocyte proteomic reprogramming, whereby these cells become a source of abnormal signals, affecting vascular and myocardial tissues, leading to meta-inflammation, atrial fibrillation, coronary artery disease, heart hypertrophy, heart failure and myocardial infarction. This review first discusses the pathophysiology and consequences of adipose tissue expansion, particularly their association with meta-inflammation and microbiota dysbiosis. We also explore the precise mechanisms involved in metabolic reprogramming in AT that represent plausible causative factors for CVD. Finally, we clarify how lifestyle changes could promote improvement in myocardiocyte function in the context of changes in AT proteomics and a better gut microbiome profile to develop effective, non-pharmacologic approaches to CVD.

Does four-week consecutive, dawn-to-sunset intermittent fasting during Ramadan affect cardiometabolic risk factors in healthy adults? A systematic review, meta-analysis, and meta-regression

AIMS

This study aimed to evaluate the effects of Ramadan diurnal intermittent fasting (RDIF; 29-30 days) on cardiometabolic risk factors (CMRF) in healthy adults, and examine the effect of various cofactors on the outcomes using sub-group meta-regression.

DATA SYNTHESIS

We conducted a systematic review and meta-analysis to measure the effect sizes of changes in CMRF in healthy adult Muslims observing RDIF. Ten scientific databases (EBSCOhost, CINAHL, Cochrane, EMBASE, PubMed/MEDLINE, Scopus, Google Scholar, ProQuest Medical, ScienceDirect, and Web of Science) were searched from the date of inception (1950) to the end of November 2020. The CMRF searched and analyzed were total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol (VLDL-C), diastolic blood pressure (DBP), and heart rate (HR). We identified 91 studies (4431 adults aged 18-85 years) conducted between 1982 and 2020 in 23 countries distributed over four continents. RDIF-induced effect sizes for CMRF were: TC (no. of studies K = 77, number of subjects N = 3705, Hedge's g = -0.092, 95% confidence interval (CI): -0.168, 0.016); TG (K = 74, N = 3591, Hedge's g = -0.127, 95% CI: -0.203, 0.051); HDL-C (K = 68, N = 3528, Hedge's g = 0.138, 95% CI: 0.051, 0.224); LDL-C (K = 65, N = 3354, Hedge's g = -0.115, 95% CI: -0.197, -0.034); VLDL-C (K = 13, N = 648, Hedge's g = -0.252, 95% CI: -0.431, 0.073), DBP (K = 32, N = 1716, Hedge's g = -0.255, 95% CI: -0.363, 0.147), and HR (K = 12, N = 674, Hedge's g = -0.082, 95% CI: -0.300, 0.136). Meta-regression revealed that the age of fasting people was a significant moderator of changes in both HDL-C (P = 0.02) and VLDL-C (P = 0.01). Male sex was the only significant moderator of changes in LDL-C (P = 0.055). Fasting time duration was the only significant moderator of HDL-C (P = 0.001) at the end of Ramadan.

CONCLUSIONS

RDIF positively impacts CMRF, which may confer short-term transient protection against cardiovascular disease among healthy people.

Caloric Restriction and Cardiovascular Health: the Good, the Bad, and the Renin-Angiotensin System

Much excitement exists over the cardioprotective and life-extending effects of caloric restriction (CR). This review integrates population studies with experimental animal research to address the positive and negative impact of mild and severe CR on cardiovascular physiology and pathophysiology, with a particular focus on the renin-angiotensin system (RAS). We also highlight the gaps in knowledge and areas ripe for future physiological research.

A Muscle-Centric Perspective on Intermittent Fasting: A Suboptimal Dietary Strategy for Supporting Muscle Protein Remodeling and Muscle Mass?

Muscle protein is constantly “turning over” through the breakdown of old/damaged proteins and the resynthesis of new functional proteins, the algebraic difference determining net muscle gain, maintenance, or loss. This turnover, which is sensitive to the nutritional environment, ultimately determines the mass, quality, and health of skeletal muscle over time. Intermittent fasting has become a topic of interest in the health community as an avenue to improve health and body composition primarily via caloric deficiency as well as enhanced lipolysis and fat oxidation secondary to attenuated daily insulin response. However, this approach belies the established anti-catabolic effect of insulin on skeletal muscle. More importantly, muscle protein synthesis, which is the primary regulated turnover variable in healthy humans, is stimulated by the consumption of dietary amino acids, a process that is saturated at a moderate protein intake. While limited research has explored the effect of intermittent fasting on muscle-related outcomes, we propose that infrequent meal feeding and periods of prolonged fasting characteristic of models of intermittent fasting may be counter-productive to optimizing muscle protein turnover and net muscle protein balance. The present commentary will discuss the regulation of muscle protein turnover across fasted and fed cycles and contrast it with studies exploring how dietary manipulation alters the partitioning of fat and lean body mass. It is our position that intermittent fasting likely represents a suboptimal dietary approach to remodel skeletal muscle, which could impact the ability to maintain or enhance muscle mass and quality, especially during periods of reduced energy availability.

Regulation of GH and GH Signaling by Nutrients

Growth hormone (GH) and insulin-like growth factor-1 (IGF-I) are pleiotropic hormones with important roles in lifespan. They promote growth, anabolic actions, and body maintenance, and in conditions of energy deprivation, favor catabolic feedback mechanisms switching from carbohydrate oxidation to lipolysis, with the aim to preserve protein storages and survival. IGF-I/insulin signaling was also the first one identified in the regulation of lifespan in relation to the nutrient-sensing. Indeed, nutrients are crucial modifiers of the GH/IGF-I axis, and these hormones also regulate the complex orchestration of utilization of nutrients in cell and tissues. The aim of this review is to summarize current knowledge on the reciprocal feedback among the GH/IGF-I axis, macro and micronutrients, and dietary regimens, including caloric restriction. Expanding the depth of information on this topic could open perspectives in nutrition management, prevention, and treatment of GH/IGF-I deficiency or excess during life.

Modulatory Effect of Intermittent Fasting on Adipose Tissue Inflammation: Amelioration of Cardiovascular Dysfunction in Early Metabolic Impairment

Cardiometabolic syndrome (CMS) is a cluster of maladaptive cardiovascular, renal, thrombotic, inflammatory, and metabolic disorders. It confers a high risk of cardiovascular mortality and morbidity. CMS is triggered by major shifts in lifestyle and dietary habits with increased consumption of refined, calorie-dense diets. Evidence indicates that diet-induced CMS is linked to Adipose tissue (AT) inflammation. This led to the proposal that adipose inflammation may be involved in metabolic derangements, such as insulin resistance and poor glycemic control, as well as the contribution to the inflammatory process predisposing patients to increased cardiovascular risk. Therefore, in the absence of direct pharmacological interventions for the subclinical phase of CMS, time restricted feeding regimens were anticipated to alleviate early metabolic damage and subsequent comorbidities. These regimens, referred to as intermittent fasting (IF), showed a strong positive impact on the metabolic state of obese and non-obese human subjects and animal models, positive AT remodeling in face of overnutrition and high fat diet (HFD) consumption, and improved CV outcomes. Here, we summarize the available evidence on the role of adipose inflammation in triggering cardiovascular impairment in the context of diet induced CMS with an emphasis on the involvement of perivascular adipose tissue. As well, we propose some possible molecular pathways linking intermittent fasting to the ameliorative effect on adipose inflammation and cardiovascular dysfunction under such circumstances. We highlight a number of targets, whose function changes in perivascular adipose tissue inflammation and could be modified by intermittent fasting acting as a novel approach to ameliorate the inflammatory status.

Metabolic Impact of Intermittent Fasting in Patients With Type 2 Diabetes Mellitus: A Systematic Review and Meta-analysis of Interventional Studies

CONTEXT

Intermittent fasting (IF) has been proposed as a weight-loss strategy with additional cardiometabolic benefits in individuals with obesity. Despite its growing popularity, the effect of IF in patients with type 2 diabetes (T2DM) remains unclear.

OBJECTIVE

We conducted a systematic review and meta-analysis to evaluate the metabolic impact of IF compared to standard diet in patients with T2DM.

METHODS

Embase, PubMed, and clinicaltrials.gov between 1950 and August 12, 2020 were searched for randomized, diet-controlled studies evaluating any IF intervention in adults with T2DM. We examined the impact of IF on weight loss and glucose-lowering by calculating pooled estimates of the absolute differences in body weight and glycated hemoglobin A1c (HbA1c) compared to a control group using a random-effects model.

RESULTS

Seven studies (n = 338 participants; mean body mass index [BMI] 35.65, mean baseline HbA1c 8.8%) met our inclusion criteria. IF induced a greater decrease in body weight by -1.89 kg (95% CI, -2.91 to -0.86 kg) compared to a regular diet, with no significant between-study heterogeneity (I2 21.0%, P = .28). The additional weight loss induced by IF was greater in studies with a heavier population (BMI > 36) (-3.43 kg [95% CI, -5.72 to -1.15 kg]) and in studies of shorter duration (≤ 4 months) (-3.73 kg [95% CI, -7.11 to -0.36 kg]). IF was not associated with further reduction in HbA1c compared to a standard diet (HbA1c -0.11% [95% CI, -0.38% to 0.17%]).

CONCLUSION

Current evidence suggests that IF is associated with greater weight loss in patients with T2DM compared with a standard diet, with a similar impact on glycemic control.

Dysbiosis, malnutrition and enhanced gut-lung axis contribute to age-related respiratory diseases

Older people are at an increased risk of developing respiratory diseases such as chronic obstructive pulmonary diseases, asthma, idiopathic pulmonary fibrosis or lung infections. Susceptibility to these diseases is partly due to the intrinsic ageing process, characterized by genomic, cellular and metabolic hallmarks and immunosenescence, and is associated with changes in the intestinal microbiota. Importantly, in the lungs, ageing is also associated with a dysbiosis and loss of resilience of the resident microbiota and alterations of the gut-lung axis. Notably, as malnutrition is often observed in the elderly, nutrition is one of the most accessible modifiable factors affecting both senescence and microbiota. This article reviews the changes affecting the lung and its resident microbiota during ageing, as well as the interconnections between malnutrition, senescence, microbiota, gut-lung axis and respiratory health. As the communication along the gut-lung axis becomes more permissive with ageing, this review also explores the evidence that the gut and lung microbiota are key players in the maintenance of healthy lungs, and as such, are potential targets for nutrition-based preventive strategies against lung disease in elderly populations.

Treatment of NAFLD with intermittent calorie restriction or low-carb high-fat diet - a randomised controlled trial

Background & Aims

The first-line treatment for non-alcoholic fatty liver disease (NAFLD) is weight reduction. Several diets have been proposed, with various effects specifically on liver steatosis. This trial compared the effects of intermittent calorie restriction (the 5:2 diet) and a low-carb high-fat diet (LCHF) on reduction of hepatic steatosis.

Methods

We conducted an open-label randomised controlled trial that included 74 patients with NAFLD randomised in a 1:1:1 ratio to 12 weeks' treatment with either a LCHF or 5:2 diet, or general lifestyle advice from a hepatologist (standard of care; SoC). The primary outcome was reduction of hepatic steatosis as measured by magnetic resonance spectroscopy. Secondary outcomes included transient elastography, insulin resistance, blood lipids, and anthropometrics.

Results

The LCHF and 5:2 diets were both superior to SoC treatment in reducing steatosis (absolute reduction: LCHF: -7.2% [95% CI = -9.3 to -5.1], 5:2: -6.1% [95% CI = -8.1 to -4.2], SoC: -3.6% [95% CI = -5.8 to -1.5]) and body weight (LCHF: -7.3 kg [95% CI = -9.6 to -5.0]; 5:2: -7.4 kg [95% CI = -8.7 to -6.0]; SoC: -2.5 kg [95% CI =-3.5 to -1.5]. There was no difference between 5:2 and LCHF (p = 0.41 for steatosis and 0.78 for weight). Liver stiffness improved in the 5:2 and SoC but not in the LCHF group. The 5:2 diet was associated with reduced LDL levels and was tolerated to a higher degree than LCHF.

Conclusions

The LCHF and 5:2 diets were more effective in reducing steatosis and body weight in patients with NAFLD than SoC, suggesting dietary advice can be tailored to meet individual preferences.

Lay summary

For a person with obesity who suffers from fatty liver, weight loss through diet can be an effective treatment to improve the condition of the liver. Many popular diets that are recommended for weight reduction, such as high-fat diets and diets based on intermittent fasting, have not had their effects on the liver directly evaluated. This study shows that both a low-carb high-fat and the 5:2 diet are effective in treating fatty liver caused by obesity.

Clinical Trials Registration

This study is registered at Clinicaltrials.gov (NCT03118310).

Lipoedema – a growing problem in Spain

Lipoedema is a chronic disease frequent in women, that causes an abnormal fat deposition in their lower limbs, with a remarkable disproportion between the upper and lower part of the body, easy bruising and pain. Despite the lack of pathognomonic tests for lipoedema, more and more patients in social networks are claiming they suffer from it, giving the disease more visibility but allowing a lot of fake information about lipoedema. Information for self-care and realistic expectations are important. Depending on the severity, the treatment includes: physical therapies, compression garments, exercise, diet, psychological support and surgical treatment.

Intermittent fasting for the prevention of cardiovascular disease

BACKGROUND

Cardiovascular disease (CVD) is the leading cause of death worldwide. Lifestyle changes are at the forefront of preventing the disease. This includes advice such as increasing physical activity and having a healthy balanced diet to reduce risk factors. Intermittent fasting (IF) is a popular dietary plan involving restricting caloric intake to certain days in the week such as alternate day fasting and periodic fasting, and restricting intake to a number of hours in a given day, otherwise known as time-restricted feeding. IF is being researched for its benefits and many randomised controlled trials have looked at its benefits in preventing CVD.

OBJECTIVES

To determine the role of IF in preventing and reducing the risk of CVD in people with or without prior documented CVD.

SEARCH METHODS

We conducted our search on 12 December 2019; we searched CENTRAL, MEDLINE and Embase. We also searched three trials registers and searched the reference lists of included papers. Systematic reviews were also viewed for additional studies. There was no language restriction applied.

SELECTION CRITERIA

We included randomised controlled trials comparing IF to ad libitum feeding (eating at any time with no specific caloric restriction) or continuous energy restriction (CER). Participants had to be over the age of 18 and included those with and without cardiometabolic risk factors. Intermittent fasting was categorised into alternate-day fasting, modified alternate-day fasting, periodic fasting and time-restricted feeding.

DATA COLLECTION AND ANALYSIS

Five review authors independently selected studies for inclusion and extraction. Primary outcomes included all-cause mortality, cardiovascular mortality, stroke, myocardial infarction, and heart failure. Secondary outcomes include the absolute change in body weight, and glucose. Furthermore, side effects such as headaches and changes to the quality of life were also noted. For continuous data, pooled mean differences (MD) (with 95% confidence intervals (CIs)) were calculated. We contacted trial authors to obtain missing data. We used GRADE to assess the certainty of the evidence.  MAIN RESULTS: Our search yielded 39,165 records after the removal of duplicates. From this, 26 studies met our criteria, and 18 were included in the pooled analysis. The 18 studies included 1125 participants and observed outcomes ranging from four weeks to six months. No studies included data on all-cause mortality, cardiovascular mortality, stroke, myocardial infarction, and heart failure at any point during follow-up. Of quantitatively analysed data, seven studies compared IF with ab libitum feeding, eight studies compared IF with CER, and three studies compared IF with both ad libitum feeding and CER. Outcomes were reported at short term (≤ 3 months) and medium term (> 3 months to 12 months) follow-up. Body weight was reduced with IF compared to ad libitum feeding in the short term (MD -2.88 kg, 95% CI -3.96 to -1.80; 224 participants; 7 studies; low-certainty evidence). We are uncertain of the effect of IF when compared to CER in the short term (MD -0.88 kg, 95% CI -1.76 to 0.00; 719 participants; 10 studies; very low-certainty evidence) and there may be no effect in the medium term (MD -0.56 kg, 95% CI -1.68 to 0.56; 279 participants; 4 studies; low-certainty evidence). We are uncertain about the effect of IF on glucose when compared to ad libitum feeding in the short term (MD -0.03 mmol/L, 95% CI -0.26 to 0.19; 95 participants; 3 studies; very-low-certainty of evidence) and when compared to CER  in the short term: MD -0.02 mmol/L, 95% CI -0.16 to 0.12; 582 participants; 9 studies; very low-certainty; medium term: MD 0.01, 95% CI -0.10 to 0.11; 279 participants; 4 studies; low-certainty evidence). The changes in body weight and glucose were not deemed to be clinically significant. Four studies reported data on side effects, with some participants complaining of mild headaches. One study reported on the quality of life using the RAND SF-36 score. There was a modest increase in the physical component summary score.

AUTHORS' CONCLUSIONS

Intermittent fasting was seen to be superior to ad libitum feeding in reducing weight. However, this was not clinically significant. There was no significant clinical difference between IF and CER in improving cardiometabolic risk factors to reduce the risk of CVD. Further research is needed to understand the safety and risk-benefit analysis of IF in specific patient groups (e.g. patients with diabetes or eating disorders) as well as the effect on longer-term outcomes such as all-cause mortality and myocardial infarction.

Time restricted eating as a weight loss intervention in adults with obesity

Objectives

Time-restricted eating (TRE) is a weight management approach in which food is consumed only within a specific period each day. The simplicity of this approach is appealing, but its efficacy is not known. The aim of this pilot cohort study was to assess adherence to TRE and its effects on weight and lipid profile.

Methods

Fifty participants with obesity attempted to follow TRE for 12 weeks. Surveys were conducted weekly over the phone to assess treatment adherence and ratings; and at 6 and 12 weeks, participants attended the clinic to be weighed, have their blood pressure taken and provide a blood sample for lipid profile. Treatment results were compared with data from previous comparable cohorts using other weight management methods.

Results

Mean age of the participants was 50 (SD = 12.0), mean weight 97kg (SD = 17.1), mean BMI = 35 (SD = 4.0) and most were female (74%). At weeks 6 and 12, 64% and 58% of participants continued to practice TRE on at least five days/week. Using the ‘last observation carried forward’ imputation, mean (SD) weight loss was 2.0 (1.7) kg and 2.6 (2.6) kg at 6 and 12 weeks. Among participants who provided follow-up data, those who adhered to the intervention for at least five days/week recorded greater weight loss than those with lower adherence (week 6: 2.5 (1.7) vs 1.0 (1.3), p = 0.003; week 12: 3.5 (2.7) vs 1.3 (2.0), p = 0.001). A total of 26% of the sample lost at least 5% of their body weight at 12 weeks. The intervention had no effect on blood pressure or lipid profile.

Conclusions

TRE results were modest, but at least on par with those achieved with more complex interventions, and weight loss did not decline at 12 weeks. A formal trial of the intervention is warranted.

Can intermittent fasting be helpful for knee osteoarthritis?

Obesity and Knee Osteoarthritis (KOA) has a proven association. The obese individuals are likely to have early and more severe KOA, and the complications and overall results of surgery are also inferior. Hence, weight reduction is of paramount importance for these individuals. Due to the inability to do intense physical activities, these individuals cannot lose weight and instead perpetually kept gaining weight. Hence, intermittent fasting as a non-operative means of weight reduction is an attractive and viable option. This review article would help sensitize the Orthopaedic Surgeons about fasting in weight reduction and assisting the KOA. Hence, the choice of intermittent fasting should be offered to obese patients with KOA for weight reduction.

Health Effects of Alternate-Day Fasting in Adults: A Systematic Review and Meta-Analysis

Background: Alternate-day fasting (ADF) method is becoming more and more popular among adults. This meta-analysis aims to evaluate the effects of ADF on adults.

Methods: Randomized controlled trials (RCTs) of ADF were searched using PubMed (1988 to March 2020), EMBASE (1995 to March 2020), and the Cochrane Controlled Trials Register. A systematic review was carried out using the Preferred Reporting Items for Systematic Reviews and Meta-analyses. The datum was calculated by RevMan version 5.3.0. The original references for relating articles were also reviewed.

Results: Seven randomized controlled trials involving 269 participants (152 in the ADF group and 117 in the control group) were studied. In this meta-analysis, compared with the control group, the ADF group showed statistically significant reductions in weight (p < 0.00001) and body mass index (p < 0.00001). Besides, the ADF group showed significant differences in terms of total cholesterol (p = 0.001), low-density lipoprotein (p = 0.01), triglycerides (p = 0.02), fat mass (p = 0.002), lean mass (p = 0.002), systolic blood pressure (p = 0.003), diastolic blood pressure (p = 0.007), and total calorie intake (p = 0.007). At the same time, the analysis demonstrated that the ADF group had a same effect compared with control group in aspects of high-density lipoprotein (p = 0.27), homeostasis model assessment-insulin resistance (p = 0.55), and fasting blood sugar (p = 0.09).

Conclusions: This meta-analysis suggests that ADF is a viable diet strategy for weight loss, and it has a substantial improvement in risk indicators for diseases in obese or normal people.

Adipose Tissue Immunomodulation: A Novel Therapeutic Approach in Cardiovascular and Metabolic Diseases

Adipose tissue is a critical regulator of systemic metabolism and bodily homeostasis as it secretes a myriad of adipokines, including inflammatory and anti-inflammatory cytokines. As the main storage pool of lipids, subcutaneous and visceral adipose tissues undergo marked hypertrophy and hyperplasia in response to nutritional excess leading to hypoxia, adipokine dysregulation, and subsequent low-grade inflammation that is characterized by increased infiltration and activation of innate and adaptive immune cells. The specific localization, physiology, susceptibility to inflammation and the heterogeneity of the inflammatory cell population of each adipose depot are unique and thus dictate the possible complications of adipose tissue chronic inflammation. Several lines of evidence link visceral and particularly perivascular, pericardial, and perirenal adipose tissue inflammation to the development of metabolic syndrome, insulin resistance, type 2 diabetes and cardiovascular diseases. In addition to the implication of the immune system in the regulation of adipose tissue function, adipose tissue immune components are pivotal in detrimental or otherwise favorable adipose tissue remodeling and thermogenesis. Adipose tissue resident and infiltrating immune cells undergo metabolic and morphological adaptation based on the systemic energy status and thus a better comprehension of the metabolic regulation of immune cells in adipose tissues is pivotal to address complications of chronic adipose tissue inflammation. In this review, we discuss the role of adipose innate and adaptive immune cells across various physiological and pathophysiological states that pertain to the development or progression of cardiovascular diseases associated with metabolic disorders. Understanding such mechanisms allows for the exploitation of the adipose tissue-immune system crosstalk, exploring how the adipose immune system might be targeted as a strategy to treat cardiovascular derangements associated with metabolic dysfunctions.

Histone Deacetylase SIRT1, Smooth Muscle Cell Function, and Vascular Diseases

Vascular smooth muscle cells (VSMCs), located in the media of artery, play key roles in maintaining the normal vascular physiological functions. Abnormality in VSMCs is implicated in vascular diseases (VDs), including atherosclerosis, abdominal aortic aneurysm (AAA), aortic dissection, and hypertension by regulating the process of inflammation, phenotypic switching, and extracellular matrix degradation. Sirtuins (SIRTs), a family of proteins containing seven members (from SIRT1 to SIRT7) in mammals, function as NAD⁺-dependent histone deacetylases and ADP-ribosyltransferases. In recent decades, great attention has been paid to the cardiovascular protective effects of SIRTs, especially SIRT1, suggesting a new therapeutic target for the treatment of VDs. In this review, we introduce the basic functions of SIRT1 against VSMC senescence, and summarize the contribution of SIRT1 derived from VSMCs in VDs. Finally, the potential new strategies based on SIRT1 activation have also been discussed with an emphasis on SIRT1 activators and calorie restriction to improve the prognosis of VDs.