Fasting - the ultimate diet?

It's About Timing: Contrasting the Metabolic Effects of Early vs. Late Time-Restricted Eating in Humans

PURPOSE OF REVIEW

Time-restricted eating (TRE), a form of intermittent fasting, restricts feeding time across the day, imposing a daily 'eating window'. The time of day when the eating window occurs could result in differential metabolic effects. Here, we describe recent intervention studies in humans assessing the metabolic consequences of an early- (i.e., eating window starting in the early morning) vs. late (i.e., eating window starting after midday)-TRE protocol.

RECENT FINDINGS

Well-controlled studies indicate that both TRE protocols effectively reduce body weight and improve altered glucose metabolism, lipid profile, inflammation, or blood pressure levels. An early-TRE (e-TRE) might have a further positive impact on improving blood glucose, insulin levels, and insulin resistance. However, the studies directly assessing the metabolic consequences of an early- vs. late-TRE have shown dissimilar findings, and more well-controlled clinical trials are needed on the metabolic benefits of these two types of TRE. Evidence suggests that an e-TRE might have enhanced metabolic results, particularly regarding glucose homeostasis. More long-term studies, including larger sample sizes, are needed to assess the metabolic, circadian, and adherence benefits, together with socio-cultural acceptance of both TRE approaches.

Fasting diets: what are the impacts on eating behaviors, sleep, mood, and well-being?

Fasting diets (FDs) have drawn great attention concerning their contribution to health and disease over the last decade. Despite considerable interest in FDs, the effect of fasting diets on eating behaviors, sleep, and mood-essential components of diet satisfaction and mental health- has not been addressed comprehensively. Understanding the critical role that fasting plays in these elements will open up potential treatment avenues that have not yet been explored. The aim of the present paper was to conduct a comprehensive critical review exploring the effects of fasting on eating behaviors, sleep, and mood. There is currently a lack of clarity regarding which fasting option yields the most advantageous effects, and there is also a scarcity of consistent trials that assess the effects of FDs in a comparable manner. Similarly, the effects and/or treatment options for utilizing FDs to modify eating and sleep behaviors and enhance mood are still poorly understood. Further researches aiming at understanding the impacts of various fasting regimes, providing new insights into the gut-brain axis and offering new treatment avenues for those with resistant anxiety and depression, are warranted. Alteration of eating behaviors can have lasting effects on various physiological parameters. The use of fasting cures can underpin ancient knowledge with scientific evidence to form a new approach to the prevention and treatment of problems associated with co-morbidities or challenges pertaining to eating behaviors. Therefore, a thorough examination of the various fasting regimens and how they impact disease patterns is also warranted.

High-intensity interval training prevents muscle mass loss in overweight Chilean young adults during a hypocaloric-Mediterranean diet: a randomized trial

The hypocaloric Mediterranean diet (MD) mainly reduces fat mass but inevitably causes a loss of skeletal muscle mass. High-intensity interval training (HIIT) seems to have advantages in preserving muscle mass during a hypocaloric regime. Our study compares body composition and metabolic changes in overweight and obese Chilean women and men after 3 months of weight loss treatment with a Mediterranean-type hypocaloric diet, HIIT, or a combination of both. The study included 83 overweight or obese women and men between the ages of 25 and 50. The subjects were randomly assigned to one of the three intervention groups: (1) MD, (2) EX, and (3) MD + EX. Baseline and post-intervention measurements included: (a) body composition by dual-beam densitometry, muscle, and fat measurements by thigh ultrasound and computed tomography; (b) handgrip and quadriceps muscle strength; (c) exercise performance by peak oxygen consumption, peak load, work efficiency, and exercise energy expenditure; and (d) metabolic parameters. Out of 83 participants, the retention rate was 49% due to low compliance with the interventions. As expected, the MD group resulted in significantly greater weight loss (MD -7%, EX -0.6% and MD + EX -5.3%) and appendicular fat mass loss (MD -11.1%, EX -2.9, MD + EX -10.2%) but was associated with significant lean tissue loss (2.8%), which was prevented by HIIT (EX -0.1 and MD + EX -0.6%). Metabolic and glycoxidative parameters remained unchanged, irrespective of changes in body composition. Hypocaloric diets remain the most effective means to lose weight and body fat. However, it induces a loss of lean body mass when not accompanied by exercise training. This study shows that HIIT prevents the loss of muscle mass caused by a hypocaloric Mediterranean diet.

Popular fad diets: An evidence-based perspective

Despite the emergence of stronger nutritional science over the past two decades, fad diets remain highly popular. However, growing medical evidence has led to the endorsement of healthy eating patterns by medical societies. This thus allows fad diets to be compared to the emerging scientific evidence as to which diets promote or damage health. In this narrative review, the most popular current fad diets are critically analyzed, including low-fat diets, vegan and vegetarian diets, low-carbohydrate diets, ketogenic diets, Paleolithic diets, and intermittent fasting. Each of these diets has some scientific merit, but each has potential deficiencies relative to the findings of nutritional science. This article also presents the common themes that emerge among the dietary guidance of leading health organizations, such as the American Heart Association and the American College of Lifestyle Medicine. While there are important distinctions between dietary recommendations emanating from various medical societies, each recommends eating more unrefined, plant-based foods, while eating fewer highly processed foods and added sugars, and avoiding excessive calorie consumption as an important nutritional strategy for the prevention and management of chronic conditions and promotion of overall health.

High-protein diet prevents fat mass increase after dieting by counteracting Lactobacillus-enhanced lipid absorption

Dietary restriction is widely used to reduce fat mass and lose weight in individuals with or without obesity; however, weight regain after dieting is still a big challenge, and the underlying mechanisms remain largely elusive. Here we show that refeeding after various types of dieting induces quick fat accumulation in mice and enhanced intestinal lipid absorption contributes to post-dieting fat mass increase. Moreover, refeeding after short-term dietary restriction is accompanied by an increase in intestinal Lactobacillus and its metabolites, which contributes to enhanced intestinal lipid absorption and post-dieting fat mass increase; however, refeeding a high-protein diet after short-term dietary restriction attenuates intestinal lipid absorption and represses fat accumulation by preventing Lactobacillus growth. Our results provide insight into the mechanisms underlying fat mass increase after dieting. We also propose that targeting intestinal Lactobacillus to inhibit intestinal lipid absorption via high-protein diet or antibiotics is likely an effective strategy to prevent obesity after dieting.

Effects of Time-Restricted Feeding and Ramadan Fasting on Body Weight, Body Composition, Glucose Responses, and Insulin Resistance: A Systematic Review of Randomized Controlled Trials

Time-restricted feeding (TRF) and Ramadan fasting (RF) have been recently associated with several health outcomes. However, it is not yet clear if they are superior to existing treatments in terms of glucose metabolism, insulin action, and weight loss. This review aims to summarize the current data on the effects of these regimes on body weight, body composition, and glycemia. An electronic search was conducted in PUBMED and SCOPUS databases up to August 2022. Twenty-four records met the inclusion criteria and underwent a risk-of-bias assessment. The main outcomes were: (a) TRF may result in moderate weight loss in individuals with overweight/obesity; when TRF is combined with caloric restriction, weight loss is >5% of the initial body weight, (b) 14 h of fasting may be as effective as 16 h in terms of weight loss, and (c) TRF may lead to improved insulin sensitivity and glycemic responses/variability throughout the day in individuals with overweight/obesity. Concerning RF, only two studies were available and thus, conclusions were not drawn. TRF may be an effective nutritional approach for weight loss, and the amelioration of glycemic control and insulin sensitivity in individuals with overweight/obesity. However, more long-term, well-designed studies are needed.

Traditional and Medical Applications of Fasting

Fasting has been practiced for millennia, for religious, ethical, or health reasons. It is also commonplace among different species, from humans, to animals, to lower eukaryotes. Research on fasting is gaining traction based on recent studies that show its role in many adaptive cellular responses such as the reduction of oxidative damage and inflammation, increase of energy metabolism, and in boosting cellular protection. In this expert review, we recount the historical evolution of fasting and we critically analyze its current medical applications, including benefits and caveats. Based on the available data, we conclude that the manipulation of dietary intake, in the form of calorie restriction, intermittent fasting, dietary restriction with the exclusion of some nutrients, prolonged fasting, and so forth, is anthropologically engraved in human culture possibly because of its positive health effects. Indeed, many studies show that fasting ameliorates many biochemical parameters related to cardiovascular and cancer risk, and neurodegeneration. Mechanistic studies are plentiful, but largely limited to cell cultures or laboratory animals. Understandably, there are no controlled trials of any form of fasting that gauge the effects on [any cause] mortality. Physicians should be aware that misinformation is pervasive and that their patients often adopt dietary regimens that are far from being clinically validated. Moreover, doctors are often unaware of their patients’ religious or traditional fasting and of its potential health effects. Based on current evidence, no long-term fasting should be undertaken without medical supervision until future research will hopefully help shed further light on fasting and its effects on human health.

The Ontario Public Does Not Understand the Difference Between Registered Dietitians and Unregulated "Nutritionists": Results from a Cross-Sectional Mixed Methods Study

Background:

Current Ontario healthcare policy permits anyone to use the title “nutritionist” and practice as a clinician regardless of education and training. The title “dietitian,” on the other hand, is protected under the Dietetics Act (1991) for use exclusively by individuals who undergo rigorous education and training in evidence-based nutrition.

Objectives:

The objectives of this study were to: identify whether the Ontario general public understands the difference between a registered dietitian (RD) and an unregulated “nutritionist;” understand experiences with RDs and “nutritionists;” and determine if the current nutrition landscape arising from gaps in healthcare policy has the potential to harm the public.

Methods:

A cross-sectional mixed methods survey study was carried out using inductive content analysis, descriptive statistics and chi-square tests.

Results:

Respondents (n = 402) did not understand the difference between RDs and “nutritionists.” Overall, public experiences have been significantly more positive when nutrition information/advice stemmed from an RD.

Implications:

This study provides justification for proposed legislative amendments to the Dietetics Act (1991) and the Regulated Health Professions Act (1991). These proposed amendments have been detailed in the full-text manuscript.

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.

Effect of toxic trace element detoxification, body fat reduction following four-week intake of the Wellnessup diet: a three-arm, randomized clinical trial

Background

Detox diet are known as a popular dieting strategies that helps toxins elimination and weight manage but there is very little clinical evidence. The Wellnessup diet (WD) used in the present study designed as a healthy meals based on organic plant based diets including various vegetables, fruits, whole grains, nuts and phytonutrients.

Methods

To evaluate the effects of 4 week intake of the WD on toxic trace element detoxification, body fat reduction, and safety parameters. Forty-five women with body mass index (BMI) of 23.5-30 kg/m² were recruited. Thirty of them were assigned 1:1 to the test group (WD, 15 subjects) and control group 1 (calorie-restricted diet, CRD, 15 subjects) in a single blind and randomized, and the remaining 15 subjects were assigned to control group 2 (maintaining regular diet, MRD). The primary outcome were toxic trace element levels in hair (29 types of heavy metals), and the secondary outcomes were changes in anthropometric and urinary organic acids.

Results

The levels of four toxic trace elements in hair decreased in the WD group after the diet compared to before the diet. Ni, Rh, Sn, and Ga were significantly lower in the WD group than in the CRD or MRD group (p < 0.05). At the end of the trial, both WD and CRD groups had lower BMI, Waist Circumference(WC), Hip Circumference(HC) and WHR compared to the baseline values (p < 0.05). Compared to the WD group, the CRD group had a greater mean change (p < 0.05) from the baseline for weight loss (- 3.22 ± 0.48 kg vs - 1.88 ± 0.95 kg vs) and fat free mass (- 2.08 kg vs - 1.09 kg). The weight, BMI, body fat mass, fat free mass, WC, and HC of the CRD group were significantly decreased compared to the MRD (p < 0.05). No significant changes in any safety parameter were observed.

Conclusions

Use of WD might have several beneficial effects and safety such as body fat reduction and improving some the element detoxification through caloric restriction but did not reducing body fat mass more than calorie-restricted diet.

Trial registration

This study was registered at Clinical Research Information Service (CRIS) of Republic of Korea (KCT0003002).

The obesity epidemic in the face of homeostatic body weight regulation: What went wrong and how can it be fixed?

Ever since the pioneering discoveries in the mid nineteen hundreds, the hypothalamus was recognized as a crucial component of the neural system controlling appetite and energy balance. The new wave of neuron-specific research tools has confirmed this key role of the hypothalamus and has delineated many other brain areas to be part of an expanded neural system sub serving these crucial functions. However, despite significant progress in defining this complex neural circuitry, many questions remain. One of the key questions is why the sophisticated body weight regulatory system is unable to prevent the rampant obesity epidemic we are experiencing. Why are pathologically obese body weight levels defended, and what can we do about it? Here we try to find answers to these questions by 1) reminding the reader that the neural controls of ingestive behavior have evolved in a demanding, restrictive environment and encompass much of the brain's major functions, far beyond the hypothalamus and brainstem, 2) hypothesizing that the current obesogenic environment impinges mainly on a critical pathway linking hypothalamic areas with the motivational and reward systems to produce uncompensated hyperphagia, and 3) proposing adequate strategies for prevention and treatment.

"Detoxify or Die": Qualitative Assessments of Ontario Nutritionists' and Dietitians' Blog Posts Related to Detoxification Diets

While the title Registered Dietitian (RD) is regulated under provincial legislation in Ontario and other Canadian provinces, the title "nutritionist" is not regulated in Ontario, which poses potential risks to consumers who place misguided trust in those proclaiming to be nutrition experts. This is concerning as nutrition is a complex health care discipline and RDs, the recognized providers of credible nutrition information, must be registered with an accredited regulatory college that requires them to have undergone rigorous training, practicum placements, entrance examinations, and continuous professional development. The purpose of this study was to determine if Ontario-based unregulated nutritionists and RDs are providing safe, evidence-based, information regarding detoxification diets. Content from 10 blog posts were qualitatively analyzed using deductive content analysis with predetermined categorization matrices. The results revealed that Ontario nutritionists promoted detox diets and provided unproven, misleading, and potentially harmful information, whereas Ontario RDs did not promote detox diets and provided evidence-based, harm-reducing information. Additionally, conflicts of interest arose only in nutritionists' blog posts. RDs provided credible references for their information while nutritionists did not. Protecting the term "nutritionist" for use exclusively by RDs under provincial legislation would be a positive step towards ensuring Ontarians are receiving the highest quality evidence-based nutrition information.

Medicine in the Penal System

BACKGROUND

Infectious diseases, substance dependencies, and dental diseases are the most important health problems affecting incarcerated persons. In Germany, for example, prisoners are 48 to 69 times more likely to be infected with the hepatitis C virus (HCV) than the general population, and 7 to 12 times more likely to be infected with the human immunodeficiency virus (HIV). The prevalence of mental illnesses is also markedly higher in the incarcerated than in the general population.

METHODS

This review is based on pertinent publications retrieved by a selective search in two databases (PubMed and Google Scholar) for any of the terms "health care," "primary health care," "mental health care"; "infectious disease," "opioid maintenance treatment," and "severe mental disorder" in conjunction with "prison," "jail," "detention," and "incarceration."

RESULTS

Among prisoners in German prisons, approximately 20% consume heroin, 20-50% suffer from alcohol dependency and abuse, and 70-85% smoke. The prevalence of tuberculosis in German prisons in 2002 was 0.1%. The provision of needles to incarcerated persons has a preventive effect on infection with hepatitis C, hepatitis B, and HIV, yet programs of this type have been discontinued in most penal facilities. In a systematic review, psychotic disorders were found in 3.6% (95% confidence interval [CI]: [3.1; 4.2]) of male inmates and 3.9% [95% CI: 2.7; 5.0] of female inmates. 25% of incarcerated persons suffer from attention-deficit-hyperac- tivity disorder. Persons recently released from prison have an above average mortality, largely due to drug intoxication.

CONCLUSION

An analysis of medical prescribing data reveals deficiencies in the provision of HCV treatment to all affected persons and in the provision of substitution treatment to persons with opiate dependency. In view of the known risks associated with imprisonment, greater emphasis should be placed on the provision of treatment for infectious diseases, substance dependencies, and mental illness, both in prison and in outpatient care after release.

Effects of short-term fasting on cancer treatment

Growing preclinical evidence shows that short-term fasting (STF) protects from toxicity while enhancing the efficacy of a variety of chemotherapeutic agents in the treatment of various tumour types. STF reinforces stress resistance of healthy cells, while tumor cells become even more sensitive to toxins, perhaps through shortage of nutrients to satisfy their needs in the context of high proliferation rates and/or loss of flexibility to respond to extreme circumstances. In humans, STF may be a feasible approach to enhance the efficacy and tolerability of chemotherapy. Clinical research evaluating the potential of STF is in its infancy. This review focuses on the molecular background, current knowledge and clinical trials evaluating the effects of STF in cancer treatment. Preliminary data show that STF is safe, but challenging in cancer patients receiving chemotherapy. Ongoing clinical trials need to unravel if STF can also diminish toxicity and increase efficacy of chemotherapeutic regimes in daily practice.

A week of Danjiki (Buddhist fasting ritual) on cardiometabolic health: a case report

Danjiki is an ascetic traditional fasting ritual in the Japanese Buddhism training. Here we present a case of a 48-year-old man who underwent a 1-week-long Danjiki fasting ritual in a remote Buddhist temple. The daily ritual consisted of waking up at 3:30 am, hiking strenuously in the steep mountains followed by meditations on the rocks, focused calligraphy of religious drawings and documents, recital of Buddhist prayer chanting, and standing under waterfalls while reciting prayers. He was allowed to drink water ad libitum and a cup of carrot juice a day. After a week of the Danjiki ritual, his body weight decreased by 5 kg. Resting metabolic rate did not change. Fasting blood glucose did not change but plasma triglyceride decreased 35 %. There were no changes in blood pressure. Arterial stiffness increased 15-25 % and endothelium-dependent vasodilation decreased 5 %. These results indicate that the Danjiki ritual produced significant weight loss but unexpectedly reduced vascular functions.

Human diet and cognition

Cognition influences what, when and how much we eat, which in turn affects the brain and hence cognition. In this overview, focusing mainly on the human literature, we start by examining cognitive influences on food and eating. This includes food preferences and choices (e.g., effects of learning, advertising, and cultural taboos), food habits relating to when and how much to eat (e.g., the concept of meals, dieting, and hunger strikes), the perception of food (e.g., the influence of appearance, food labels, and conceptions of naturalness), and how food perception is influenced by expertise. We also review how these various influences are disrupted by abnormalities of cognition (e.g., Gourmand syndrome, amnesia, and anorexia nervosa). The second part of the overview focuses on how diet affects cognition. We start by looking at the acute effects of diet, notably the impact of breakfast on cognitive performance in children. This is followed by a review of the effects of extended dietary exposures-years and lifetimes of particular diets. Here we look at the impacts of protein-energy malnourishment and Western-style diets, and their different, but adverse affects on cognition, and the beneficial effects on cognition of breast-feeding and certain dietary practices. We then outline how diet and cooking may have allowed the evolution of the large energy-hungry human brain. This overview serves to illustrate the multiple interactions that exist between cognition and diet, their importance to health and disease, and their impact on thinking about the role of conscious processes in decision making. WIREs Cogn Sci 2014, 5:463-475. doi: 10.1002/wcs.1290 For further resources related to this article, please visit the WIREs website.

CONFLICT OF INTEREST

The authors have declared no conflicts of interest for this article.

Imposed rate and extent of weight loss in obese men and adaptive changes in resting and total energy expenditure

OBJECTIVES

Weight loss (WL) is associated with a decrease in total and resting energy expenditure (EE). We aimed to investigate whether (1) diets with different rate and extent of WL determined different changes in total and resting EE and if (2) they influenced the level of adaptive thermogenesis, defined as the decline in total or resting EE not accounted by changes in body composition.

METHODS

Three groups of six, obese men participated in a total fast for 6 days to achieve a 5% WL and a very low calorie (VLCD, 2.5 MJ/day) for 3 weeks or a low calorie (LCD, 5.2 MJ/day) diet for 6 weeks to achieve a 10% WL. A four-component model was used to measure body composition. Indirect calorimetry was used to measure resting EE. Total EE was measured by doubly labelled water (VLCD, LCD) and 24-hour whole-body calorimetry (fasting).

RESULTS

VLCD and LCD showed a similar degree of metabolic adaptation for total EE (VLCD = -6.2%; LCD = -6.8%). Metabolic adaptation for resting EE was greater in the LCD (-0.4 MJ/day, -5.3%) compared to the VLCD (-0.1 MJ/day, -1.4%) group. Resting EE did not decrease after short-term fasting and no evidence of adaptive thermogenesis (+0.4 MJ/day) was found after 5% WL. The rate of WL was inversely associated with changes in resting EE (n = 30, r = 0.-42, p=0.01).

CONCLUSIONS

The rate of WL did not appear to influence the decline in total EE in obese men after 10% WL. Approximately 6% of this decline in total EE was explained by mechanisms of adaptive thermogenesis.

Development and validation of a Lao Juan questionnaire

OBJECTIVES

Lao Juan (LJ, ) is a syndrome described in Chinese medicine (CM) that manifests with fatigue, fever, spontaneous sweating, indigestion, work-induced pain, weakness of the limbs, and shortness of breath. The present study was conducted to examine the reliability and validity of a Lao Juan Questionnaire (LJQ).

METHODS

A total of 151 outpatients and 73 normal subjects were asked to complete the LJQ. Seventy-three normal subjects were additionally asked to complete the Chalder Fatigue Scale (CFS). Twelve clinicians determined whether the 151 outpatients exhibited LJ or not. The internal consistency and construct validity for the LJQ were estimated using data from the outpatient subjects. The CFS data were used to examine the concurrent validity of the LJQ. Total LJQ scores and the clinicians᾿diagnoses of the outpatients were used to perform receiver operating characteristics (ROC) curve analyses and to define an optimum cut-off score for the LJQ.

RESULTS

The 19-item LJQ had satisfactory internal consistency (α=0.828) and concurrent validity, with significant correlations between the LJQ and the CFS subscales. In the test of construct validity using principal component analysis, a total of six factors were extracted, and the overall variance explained by all factors was 59.5%. In ROC curve analyses, the sensitivity, specificity, and area under the curve were 76.0%, 59.2%, and 0.709, respectively. The optimum cut-off score was defined as six points.

CONCLUSIONS

Our results suggest that the LJQ is a reliable and valid instrument for evaluating LJ.

The onset of daily torpor is regulated by the same low body mass in lean mice and in mice with diet-induced obesity

Effects of reducing body mass on body core temperature and locomotor activity of mice originally kept on conventional rodent diet (Group-1) were compared to those made obese by feeding them a high-fat diet (Group-2), both groups being kept at a cool ambient temperature. Based on earlier experience, threshold torpor core temperature of 31° was chosen as the endpoint to decreasing body mass. It was hypothesized that the onset of this hypothermia develops in obese mice only when their body mass approaches a similar low body mass as in lean mice. Mice in Group-1 maintained nocturnal core temperature but developed marked daytime hypothermia of 30–31°C with their body mass approaching 20 g by this time. Mice in Group-2 could maintain normal circadian temperature rhythm for 3 weeks before similar daytime hypothermia started to develop while their body mass dropped also to about 20 g. Mice belonging to Group-1 or Group-2 could regain original body mass after re-feeding with the original diet within 2 days or 5 weeks, respectively. In the course of the development of daily torpor, nighttime normothermia was accompanied by progressive increases in locomotor activity in both groups of mice. It is concluded that in mice a marked fall of daytime body core temperature is only induced when a similar low critical body mass is reached, irrespective of the initial body mass. In other words, in both groups of mice the nutritional state determines the threshold for the thermoregulatory change during torpor.

Fasting for weight loss: an effective strategy or latest dieting trend?

With the increasing obesity epidemic comes the search for effective dietary approaches for calorie restriction and weight loss. Here I examine whether fasting is the latest 'fad diet' as portrayed in popular media and discuss whether it is a safe and effective approach or whether it is an idiosyncratic diet trend that promotes short-term weight loss, with no concern for long-term weight maintenance. Fasting has long been used under historical and experimental conditions and has recently been popularised by 'intermittent fasting' or 'modified fasting' regimes, in which a very low-calorie allowance is allowed, on alternate days (ADF) or 2 days a week (5:2 diet), where 'normal' eating is resumed on non-diet days. It is a simple concept, which makes it easy to follow with no difficult calorie counting every other day. This approach does seem to promote weight loss, but is linked to hunger, which can be a limiting factor for maintaining food restriction. The potential health benefits of fasting can be related to both the acute food restriction and chronic influence of weight loss; the long-term effect of chronic food restriction in humans is not yet clear, but may be a potentially interesting future dietary strategy for longevity, particularly given the overweight epidemic. One approach does not fit all in the quest to achieve body weight control, but this could be a dietary strategy for consideration. With the obesity epidemic comes the search for dietary strategies to (i) prevent weight gain, (ii) promote weight loss and (iii) prevent weight regain. With over half of the population of the United Kingdom and other developed countries being collectively overweight or obese, there is considerable pressure to achieve these goals, from both a public health and a clinical perspective. Certainly not one dietary approach will solve these complex problems. Although there is some long-term success with gastric surgical options for morbid obesity, there is still a requirement for dietary approaches for weight management for the overweight and obese population, particularly as invasive interventions carry post-operative risk of death due to complications. Effective dietary interventions are required that promote long-term adherence and sustained beneficial effects on metabolic and disease markers. In general, such interventions need to be palatable and satiating, meet minimal nutritional requirements, promote loss of fat and preserve lean body mass, ensure long-term safety, be simple to administer and monitor and have widespread public health utility. Intermittent fasting or alternate day fasting may be an option for achieving weight loss and maintenance.

Detox diets for toxin elimination and weight management: a critical review of the evidence

Detox diets are popular dieting strategies that claim to facilitate toxin elimination and weight loss, thereby promoting health and well-being. The present review examines whether detox diets are necessary, what they involve, whether they are effective and whether they present any dangers. Although the detox industry is booming, there is very little clinical evidence to support the use of these diets. A handful of clinical studies have shown that commercial detox diets enhance liver detoxification and eliminate persistent organic pollutants from the body, although these studies are hampered by flawed methodologies and small sample sizes. There is preliminary evidence to suggest that certain foods such as coriander, nori and olestra have detoxification properties, although the majority of these studies have been performed in animals. To the best of our knowledge, no randomised controlled trials have been conducted to assess the effectiveness of commercial detox diets in humans. This is an area that deserves attention so that consumers can be informed of the potential benefits and risks of detox programmes.

Fasting mitigates immediate hypersensitivity: a pivotal role of endogenous D-beta-hydroxybutyrate

Background

Fasting is a rigorous type of dietary restriction that is associate with a number of health benefits. During fasting, ketone bodies significantly increase in blood and become major body fuels, thereby sparing glucose. In the present study, we investigated effects of fasting on hypersensitivity. In addition, we also investigated the possible role of D-beta-hydroxybutyrate provoked by fasting in the attenuation of immediate hypersensitivity by fasting.

Methods

Effects of fasting on systemic anaphylaxis were examined using rat model of toluene 2, 4-diisocyanate induced nasal allergy. In addition to food restriction, a ketogenic high-fat and low-carbohydrate diet that accelerates fatty acid oxidation and systemic instillation of D-beta-hydroxybutyrate were employed to elevate internal D-beta-hydroxybutyrate concentration. We assessed relationship between degranulation of rat peritoneal mast cells and internal D-beta-hydroxybutyrate concentration in each treatment. Changes in [Ca²⁺]i responses to compound 48/80 were analyzed in fura 2-loaded rat peritoneal mast cells derived from the ketogenic diet and fasting.

Results

Immediate hypersensitivity reaction was significantly suppressed by fasting. A significant reduction in mast cells degranulation, induced by mast cell activator compound 48/80, was observed in rat peritoneal mast cells delivered from the 24 hours fasting treatment. In addition, mast cells delivered from a ketogenic diet and D-beta-hydroxybutyrate infusion treatment also had reduced mast cell degranulation and systemic D-beta-hydroxybutyrate concentrations were elevated to similar extent as the fasting state. The peak increase in [Ca²⁺]i was significantly lower in the ketogenic diet and fasting group than that in the control diet group.

Conclusions

The results of the present study demonstrates that fasting suppress hypersensitivity reaction, and indicate that increased level of D-beta-hydroxybutyrate by fasting plays an important role, via the stabilization of mast cells, in suppression of hypersensitivity reaction.

Retrospective long-term comparison of naturopathic fasting therapy and weight reduction diet in overweight patients

In a follow-up study overweight and obese patients fasting according to Buchinger (modified) and a control group treated by a weight reduction diet in the context of an inpatient naturopathic complex treatment were compared using a questionnaire developed for a standardized phone interview 6.8 ± 1.1 years after inpatient treatment. During the inpatient treatment the fasting patients significantly more body weight, but at the time of the interview significantly more weight was gained again. 10.7% of the fasting patients and 31.9% of the control group lowered their weight at least 5% of their initial weight up to the interview. 42% of the fasting and 74% of the control group persistently changed their diet. The control group followed a significantly higher number of trained nutritional aspects. 21% of the fasting and 40% of the control group increased their leisure activity permanently. Continued improvement in quality of life was achieved by 16% of the fasting patients and 28% of the control group. The fasting therapy, carried out as part of the inpatient naturopathic complex treatment, turned out to be less suitable for the treatment of overweight and obesity compared to standard therapy. One likely determinant is the minor poststationary lifestyle modification.

Metabolite and transcriptome analysis during fasting suggest a role for the p53-Ddit4 axis in major metabolic tissues

BACKGROUND

Fasting induces specific molecular and metabolic adaptions in most organisms. In biomedical research fasting is used in metabolic studies to synchronize nutritional states of study subjects. Because there is a lack of standardization for this procedure, we need a deeper understanding of the dynamics and the molecular mechanisms in fasting.

RESULTS

We investigated the dynamic changes of liver gene expression and serum parameters of mice at several time points during a 48 hour fasting experiment and then focused on the global gene expression changes in epididymal white adipose tissue (WAT) as well as on pathways common to WAT, liver, and skeletal muscle. This approach produced several intriguing insights: (i) rather than a sequential activation of biochemical pathways in fasted liver, as current knowledge dictates, our data indicates a concerted parallel response; (ii) this first characterization of the transcriptome signature of WAT of fasted mice reveals a remarkable activation of components of the transcription apparatus; (iii) most importantly, our bioinformatic analyses indicate p53 as central node in the regulation of fasting in major metabolic tissues; and (iv) forced expression of Ddit4, a fasting-regulated p53 target gene, is sufficient to augment lipolysis in cultured adipocytes.

CONCLUSIONS

In summary, this combination of focused and global profiling approaches provides a comprehensive molecular characterization of the processes operating during fasting in mice and suggests a role for p53, and its downstream target Ddit4, as novel components in the transcriptional response to food deprivation.

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The objective of this study was to examine the influence of Ramadan fast on appetite sensations, nutritional intakes and body weight in Malians with type 2 diabetes. Appetite sensations were assessed before Ramadan and then at the second, ninth, and sixteenth days of Ramadan (period). A total of 24 subjects recorded their appetite sensations every 2 h between 0800 and 2200 h using visual analogue scales. Daily energy intakes were estimated by a 48-h food recall (before and during Ramadan). Results showed a significant sex effect for desire to eat (p < 0.04) and a significant period effect for desire to eat and fullness (p < 0.01). Significant sex by period interactions were observed for fullness (p < 0.001), desire to eat (p < 0.01), and prospective food consumption (p < 0.03). Moreover, significant sex by period by time interactions were found for all appetite sensations (p < 0.007). Interaction effects were mainly explained by sex differences in appetite sensations before rather than during Ramadan. Although a significant body weight loss was observed in men and a significant decrease in waist circumference was found in women (p < 0.05), no significant changes in reported average daily energy intakes were observed in either men or women. According to these preliminary results, Ramadan fasting has an impact on appetite sensations that is probably not the same in men and women.

In-Patient Treatment of Fibromyalgia: A Controlled Nonrandomized Comparison of Conventional Medicine versus Integrative Medicine including Fasting Therapy

Fibromyalgia poses a challenge for therapy. Recent guidelines suggest that fibromyalgia should be treated within a multidisciplinary therapy approach. No data are available that evaluated multimodal treatment strategies of Integrative Medicine (IM). We conducted a controlled, nonrandomized pilot study that compared two inpatient treatment strategies, an IM approach that included fasting therapy and a conventional rheumatology (CM) approach. IM used fasting cure and Mind-Body-Medicine as specific methods. Of 48 included consecutive patients, 28 were treated with IM, 20 with CM. Primary outcome was change in the Fibromyalgia Impact Questionnaire (FIQ) score after the 2-week hospital stay. Secondary outcomes included scores of pain, depression, anxiety, and well being. Assessments were repeated after 12 weeks. At 2 weeks, there were significant improvements in the FIQ (P < 0.014) and for most of secondary outcomes for the IM group compared to the CM group. The beneficial effects for the IM approach were reduced after 12 weeks and no longer statistically significant with the exception of anxiety. Findings indicate that a multimodal IM treatment with fasting therapy might be superior to CM in the short term and not inferior in the mid term. Longer-term studies are warranted to assess the clinical impact of integrative multimodal treatment in fibromyalgia.

A mathematical model of weight loss under total starvation: evidence against the thrifty-gene hypothesis

The thrifty-gene hypothesis (TGH) posits that the modern genetic predisposition to obesity stems from a historical past where famine selected for genes that promote efficient fat deposition. It has been previously argued that such a scenario is unfeasible because under such strong selection any gene favouring fat deposition would rapidly move to fixation. Hence, we should all be predisposed to obesity: which we are not. The genetic architecture of obesity that has been revealed by genome-wide association studies (GWAS), however, calls into question such an argument. Obesity is caused by mutations in many hundreds (maybe thousands) of genes, each with a very minor, independent and additive impact. Selection on such genes would probably be very weak because the individual advantages they would confer would be very small. Hence, the genetic architecture of the epidemic may indeed be compatible with, and hence support, the TGH. To evaluate whether this is correct, it is necessary to know the likely effects of the identified GWAS alleles on survival during starvation. This would allow definition of their advantage in famine conditions, and hence the likely selection pressure for such alleles to have spread over the time course of human evolution. We constructed a mathematical model of weight loss under total starvation using the established principles of energy balance. Using the model, we found that fatter individuals would indeed survive longer and, at a given body weight, females would survive longer than males, when totally starved. An allele causing deposition of an extra 80 g of fat would result in an extension of life under total starvation by about 1.1-1.6% in an individual with 10 kg of fat and by 0.25-0.27% in an individual carrying 32 kg of fat. A mutation causing a per allele effect of 0.25% would become completely fixed in a population with an effective size of 5 million individuals in 6000 selection events. Because there have probably been about 24,000 famine events since the evolution of hominins 4 million years ago, there has been ample time even for genes with only very minor impacts on adiposity to move to fixation. The observed polymorphic variation in the genes causing the predisposition to obesity is incompatible with the TGH, unless all these single nucleotide polymorphisms (SNPs) arose in the last 900,000 years, a requirement we know is incorrect. The TGH is further weakened by the observation of no link between the effect size of these SNPs and their prevalence, which would be anticipated under the TGH model of selection if all the SNPs had arisen in the last 900,000 years.

Neuroprotection by dietary restriction and the PPAR transcription complex

Although the pathophysiology of neurodegenerative diseases is distinct for each disease, considerable evidence suggests that a single manipulation, dietary restriction, is strikingly protective against a wide range of such diseases. Thus pharmacological mimetics of dietary restrictions could prove widely protective across a range of neurodegenerative diseases. The PPAR transcription complex functions to re-program gene expression in response to nutritional deprivation as well as in response to a wide variety of lipophilic compounds. In mammals there are three PPAR homologs, which dimerize with RXR homologs and recruit coactivators Pgc1-alpha and Creb-binding protein (Cbp). PPARs are currently of clinical interest mainly because PPAR activators are approved for use in humans to reduce lipidemia and to improve glucose control in Type 2 diabetic patients. However, pharmacological enhancement of the activity of the PPAR complex is neuroprotective across a wide variety of models for neuropathological processes, including stroke, Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease. Conversely activity of the PPAR transcriptional complex is reduced in a variety of neuropathological processes. The main mechanisms mediating the neuroprotective effects of the PPAR transcription complex appear to be re-routing metabolism away from glucose metabolism and toward alternative subtrates, and reduction in inflammatory processes. Recent evidence suggests that the PPAR transcriptional complex may also mediate protective effects of dietary restriction on neuropathological processes. Thus this complex represents one of the most promising for the development of pharmacological treatment of neurodegenerative diseases.

Gene expression profile change and associated physiological and pathological effects in mouse liver induced by fasting and refeeding

Food availability regulates basal metabolism and progression of many diseases, and liver plays an important role in these processes. The effects of food availability on digital gene expression profile, physiological and pathological functions in liver are yet to be further elucidated. In this study, we applied high-throughput sequencing technology to detect digital gene expression profile of mouse liver in fed, fasted and refed states. Totally 12162 genes were detected, and 2305 genes were significantly regulated by food availability. Biological process and pathway analysis showed that fasting mainly affected lipid and carboxylic acid metabolic processes in liver. Moreover, the genes regulated by fasting and refeeding in liver were mainly enriched in lipid metabolic process or fatty acid metabolism. Network analysis demonstrated that fasting mainly regulated Drug Metabolism, Small Molecule Biochemistry and Endocrine System Development and Function, and the networks including Lipid Metabolism, Small Molecule Biochemistry and Gene Expression were affected by refeeding. In addition, FunDo analysis showed that liver cancer and diabetes mellitus were most likely to be affected by food availability. This study provides the digital gene expression profile of mouse liver regulated by food availability, and demonstrates the main biological processes, pathways, gene networks and potential hepatic diseases regulated by fasting and refeeding. These results show that food availability mainly regulates hepatic lipid metabolism and is highly correlated with liver-related diseases including liver cancer and diabetes.

Fasting vs dietary restriction in cellular protection and cancer treatment: from model organisms to patients

The dietary recommendation for cancer patients receiving chemotherapy, as described by the American Cancer Society, is to increase calorie and protein intake. Yet, in simple organisms, mice, and humans, fasting--no calorie intake--induces a wide range of changes associated with cellular protection, which would be difficult to achieve even with a cocktail of potent drugs. In mammals, the protective effect of fasting is mediated, in part, by an over 50% reduction in glucose and insulin-like growth factor 1 (IGF-I) levels. Because proto-oncogenes function as key negative regulators of the protective changes induced by fasting, cells expressing oncogenes, and therefore the great majority of cancer cells, should not respond to the protective signals generated by fasting, promoting the differential protection (differential stress resistance) of normal and cancer cells. Preliminary reports indicate that fasting for up to 5 days followed by a normal diet, may also protect patients against chemotherapy without causing chronic weight loss. By contrast, the long-term 20 to 40% restriction in calorie intake (dietary restriction, DR), whose effects on cancer progression have been studied extensively for decades, requires weeks-months to be effective, causes much more modest changes in glucose and/or IGF-I levels, and promotes chronic weight loss in both rodents and humans. In this study, we review the basic as well as clinical studies on fasting, cellular protection and chemotherapy resistance, and compare them to those on DR and cancer treatment. Although additional pre-clinical and clinical studies are necessary, fasting has the potential to be translated into effective clinical interventions for the protection of patients and the improvement of therapeutic index.

2D-electrophoresis and multiplex immunoassay proteomic analysis of different body fluids and cellular components reveal known and novel markers for extended fasting

Background

Proteomic technologies applied for profiling human biofluids and blood cells are considered to reveal new biomarkers of exposure or provide insights into novel mechanisms of adaptation.

Methods

Both a non-targeted (classical 2D-electrophoresis combined with mass spectrometry) as well as a targeted proteomic approach (multiplex immunoassay) were applied to investigate how fasting for 36 h, as compared to 12 h, affects the proteome of platelets, peripheral blood mononuclear cells (PBMC), plasma, urine and saliva collected from ten healthy volunteers.

Results

Between-subject variability was highest in the plasma proteome and lowest in the PBMC proteome. Random Forests analysis performed on the entire dataset revealed that changes in the level of the RhoGDI2 protein in PBMC and plasma ApoA4 levels were the two most obvious biomarkers of an extended fasting. Random Forests (RF) analysis of the multiplex immunoassay data revealed leptin and MMP-3 as biomarkers for extended fasting. However, high between-subject variability may have masked the extended fasting effects in the proteome of the biofluids and blood cells.

Conclusions

Identification of significantly changed proteins in biofluids and blood cells using a non-targeted approach, together with the outcome of targeted analysis revealed both known and novel markers for a 36 h fasting period, including the cellular proteins RhoGDI2 and CLIC1, and plasma proteins ApoA4, leptin and MMP-3. The PBMC proteome exhibited the lowest between-subject variability and therefore these cells appear to represent the best biosamples for biomarker discovery in human nutrigenomics.

Prolonged fasting as a method of mood enhancement in chronic pain syndromes: a review of clinical evidence and mechanisms

Periods of deliberate fasting with restriction to intake of solid food are practiced worldwide, mostly based on a traditional, cultural, or religious background. Recent evidence from clinical trials shows that medically supervised modified fasting (200-500 kcal nutritional intake/day) with periods from 7 to 21 days is efficacious in the treatment of rheumatic diseases and chronic pain syndromes. Here, fasting is frequently accompanied by increased alertness and mood enhancement. The beneficial claims of fasting are supported by experimental research, which has found fasting to be associated with increased brain availability of serotonin, endogenous opioids, and endocannabinoids. Fasting-induced neuroendocrine activation and mild cellular stress response with increased production of neurotrophic factors may also contribute to the mood enhancement of fasting. Fasting treatments may be useful as an adjunctive therapeutic approach in chronic pain patients. The mood-enhancing and pain-relieving effect of therapeutic fasting should be further evaluated in randomized clinical trials.

The transcriptomic signature of fasting murine liver

Background

The contribution of individual organs to the whole-body adaptive response to fasting has not been established. Hence, gene-expression profiling, pathway, network and gene-set enrichment analysis and immunohistochemistry were carried out on mouse liver after 0, 12, 24 and 72 hours of fasting.

Results

Liver wet weight had declined ~44, ~5, ~11 and ~10% per day after 12, 24, 48 and 72 hours of fasting, respectively. Liver structure and metabolic zonation were preserved. Supervised hierarchical clustering showed separation between the fed, 12–24 h-fasted and 72 h-fasted conditions. Expression profiling and pathway analysis revealed that genes involved in amino-acid, lipid, carbohydrate and energy metabolism responded most significantly to fasting, that the response peaked at 24 hours, and had largely abated by 72 hours. The strong induction of the urea cycle, in combination with increased expression of enzymes of the tricarboxylic-acid cycle and oxidative phosphorylation, indicated a strong stimulation of amino-acid oxidation peaking at 24 hours. At this time point, fatty-acid oxidation and ketone-body formation were also induced. The induction of genes involved in the unfolded-protein response underscored the cell stress due to enhanced energy metabolism. The continuous high expression of enzymes of the urea cycle, malate-aspartate shuttle, and the gluconeogenic enzyme Pepck and the re-appearance of glycogen in the pericentral hepatocytes indicate that amino-acid oxidation yields to glucose and glycogen synthesis during prolonged fasting.

Conclusion

The changes in liver gene expression during fasting indicate that, in the mouse, energy production predominates during early fasting and that glucose production and glycogen synthesis become predominant during prolonged fasting.

Long-term weight loss and weight-loss maintenance strategies

It has been suggested that about 20% of subjects undergoing weight-loss programmes can achieve a certain degree of long-term success. At present, surgery remains the only method resulting in long-term sustained weight loss, but access remains restricted. Hence it is important to analyse, in addition to pharmacotherapy, the methods to improve the effects of diet, exercise and behavioural modification. Since these techniques are less spectacular than others, there is a risk that their potential will be overlooked, in spite of the fact that they remain the main alternative for most subjects undergoing weight-loss therapy. This review summarizes realistic treatment alternatives and also provides data from a day care treatment, a strategy not much reported in the literature. This is a standard treatment modality for diabetes but less common in obesity treatment.