Restriction Of Energy Intake Research Articles

Role of gastrointestinal appetite hormones in the success of body mass loss during interventions based on exercise combined with restricted energy intake diets with different fat and carbohydrate content

Restriction of energy intake is an effective strategy for achieving body mass loss(1). However, it leads to gastrointestinal appetite hormonal changes, which are expected to enhance hunger, reduce satiety, and possibly impair the ability to comply with prescribed intervention(2). Exercise interventions, on the other hand, did not modify gastrointestinal appetite hormones(3) and there is some evidence that postprandial appetite hormone responses after a low carbohydrate-high fat meal (LCHF) are more favorable than after high carbohydrate-low fat meal (HCLF) meal (4). This study investigated how energy-restricted diets based on LCHF and HCLF meals and combined with exercise affect body weight, and gastrointestinal appetite hormones and explored the relationship between body mass changes and changes in gastrointestinal appetite hormones.Twenty-seven overweight and obese females (age: 35 ± 9.35 years, BMI: 31.64 ± 5.08 kg/m2) completed a randomized parallel design study and underwent a 4-week intervention consisting of brisk walking combined with either consumption of calorie-restricted HCLF or LCHF diet. Participants underwent a 5-hour experimental trial before and after the interventions, which included body weight measurements and fasting and postprandial blood sample collection for gastrointestinal appetite hormone measurements.Both interventions significantly reduced body mass (HCLF group, −2.1 ± 1.7 Kg: LCHF group, -1.7 ± 1.7 Kg, P < 0.05 for both groups), but changes between the groups were not significant (P>0.05). Body mass changes were individual and ranged from -0.4 kg to −5.3 kg and from +1 kg to −4.4 kg in the HCLF and LCHF groups, respectively. The interventions had no impact on mean values of time- averaged postprandial concentrations of ghrelin, PYY, and GLP-1 but there was large individual variability in changes of these hormones. Results combined from both groups revealed that changes in ghrelin ranged from +549.3 to -407.7 pg/ml, in PYY from −132.5 to + 96.4 pg/ml and in GLP-1 from −6.6 to +19.5 pg/ml. Correlation, investigated on the data from both groups combined, between changes in body mass and changes in ghrelin (r = −0.18, P= 0.41), PYY (r = −0.04, P =0.87), and GLP-1 (r = 0.11, P = 0.64) were not significant.In conclusion, the extent of body mass loss during interventions based on restricted energy intake diets combined with exercise is not related to the carbohydrate and fat content of the diet. Our findings also suggest that the success of body mass loss cannot be predicted by changes in postprandial concentrations of gastrointestinal appetite hormones.

Energy and protein levels in dairy cow diets to recover milk ethanol stability

The objective of this study was to evaluate the effect of energy and protein in the diet on the recovery of milk ethanol stability (MES) induced by feed restriction. Twelve Holstein and Holstein x Jersey crossbred cows with an average of 146 ± 50 d in milk, 575.4 ± 70 kg of body weight, and 18.93 ± 5.46 kg/d of milk yield were distributed in a 3x3 Latin square design with 3 treatments and 3 experimental periods. Each experimental period lasted 24 d, comprising 3 phases: a 13-d adaptation phase (100E+100P), a 4-d induction phase for milk ethanol instability (50E+50P), and a 7-d recovery phase for MES (3 treatments). The 3 treatments during the recovery phase consisted of 3 diets aiming to meet the requirements of energy and protein (100E+100P), only energy (100E+50P), or only protein (50E+100P). The diet during the adaptation and induction phases was common for all cows. The energy and protein levels to meet each cow's requirements were based on the group average. Restriction of energy and protein reduced dry matter, crude protein, and total digestive nutrient intake for cows fed 100E+50P and 50E+100P. The lowest body weight was observed for cows fed 50E+100P, with no difference for body condition score. During the induction phase, MES "was" reduced by 9 percentage units. Cows fed 100E+100P recovered MES in the first days of the recovery phase, while 100E+50P slightly improved MES, and 50E+100P had a constant decrease in MES. Cows fed 100E+50P and 50E+100P produced, respectively, 3.6 and 5.9 kg less milk than those fed 100E+100P. The 50E+100P treatment exhibited the highest milk fat content and somatic cell score, along with the lowest milk lactose content. Protein content was higher in the 100E+100P treatment. Cows fed 50E+100P showed higher serum albumin levels compared with those on the 100E+100P treatment, not differing from the 100E+50P treatment. We concluded that the complete recovery of MES in cows with feed restrictions is possible only by supplying both the energy and protein requirements in the cows' diet. However, restricting energy intake poses a greater limitation on MES recovery compared with restricting protein.

Regulation of Aging Processes: A Perspective of Dietary Restriction Models

The moderate restriction of dietary energy intake (dietary restriction: DR) extends the lifespan and health span of various laboratory animals, suggesting that it delays the aging process inherent in many animal species. Attenuated growth hormone and insulin-like growth factor-1 (IGF-1) signaling caused by mutations also increases the lifespan of mice, even those allowed to feed freely. In nematodes, the Daf16, mammalian Forkhead box O (FoxO) transcription factor, was shown to be required for lifespan extension in response to reduced IGF-1 signaling. Because DR also decreases the plasma concentration of IGF-1 in mammals, the IGF-1-FoxO axis may play a central role in the lifespan extension effect of DR and, thus, retardation of aging. Studies using knockout mice under DR conditions revealed the importance of FoxO1 and nuclear factor erythroid-derived 2-like 2 (Nrf2) in tumor suppression, and FoxO3 in lifespan extension. Human genomic studies also identified a strong association between a FOXO3 single nucleotide polymorphism and longevity. The aging mechanism is the most important risk factor for disease and frailty in aging humans. Therefore, further research on the application of DR to humans, the development of compounds and drugs that mimic the effects of DR, and mechanisms underlying FOXO3 polymorphisms for longevity is highly relevant to extending the human health span.

Possible Anti-Obesity Role of Flavonoids Through Brown Adipose Tissue

Worldwide, the incidence of overweight and obesity is increasing day by day, and this makes the control of body weight and complications a primary health problem. Weight loss diet therapy has long been a primary role in the prevention and management of obesity. Evidence supporting the specific anti-obesity effects of certain nutrient components, in particular, polyphenolic compounds, are increasing, as well as a strategy to limit energy intake to achieve control of body weight. Active brown adipose tissue in adult individuals is gaining interest as a new and feasible target for controlling body weight by triggering and increasing energy expenditure. Flavonoids are one of the polyphenolic compounds that draw attention by regulating non-shivering thermogenesis. Although each flavonoid has its health benefits; many phytochemical compounds classified as flavonoids have an anti-obesity effect by regulating oxidation, synthesis, uptake, and transport of fatty acids. In this study, current studies on the therapeutic effect of flavonoids on obesity by regulating energy expenditure through various mechanisms of action in brown adipose tissue are reviewed.

Hungry brain: about the possible contribution of neurotrophic factors to anorexia nervosa

Introduction: Anorexia nervosa (AN) is an eating disorder characterized by restricted energy intake leading to weight loss below the healthy range. It is accompanied by anxiety and distorted body perception. While the disorder often manifests during adolescence, there is a noted decrease in the average age of onset, with an increasing number of cases in childhood. Successful treatment and maintenance of healthy body weight require an understanding of the complex etiology of AN, encompassing both psychosocial and specific biological factors. Material and methods: For the review, databases PubMed, Cochrane, and Google Scholar were utilized, searching for the following keywords: anorexia nervosa, neurotrophins, neurotrophin 3, neurotrophin 4, BDNF, nerve growth factor, from the inception of the databases until September 2023. Discussion: In the biological context, neurotrophic growth factors such as neurotrophin 3 (NT-3), neurotrophin 4 (NT-4), brainderived neurotrophic factor (BDNF), and nerve growth factor (NGF) may play a significant role in the etiopathogenesis of AN. These substances are involved in processes such as neuroprotection, proliferation, maturation, and survival of neurons in both the central and peripheral nervous systems. They regulate neuronal plasticity, impact the production of neurotransmitters, and control synaptic activity. BDNF and neurotrophin 3 influence the serotoninergic and noradrenergic systems, which may be associated with neurobiological processes responsible for anxiety and mood disorders. Conclusions: Understanding the role of neurotrophins in AN has the potential to lead to more effective and personalized therapies, enabling a better comprehension of the biological mechanisms of this disorder and the development of targeted pharmacological interventions. Keywords: anorexia nervosa, bdnf, neurotrophin 3, neurotrophin 4, nerve growth factor

The Role of Fueling Nutrition in Athletic Performance

Abstract Physical activity, athletic performance and recovery from exercise are enhanced by optimal nutrition. This paper couples a rigorous, systematic, evidence-based analysis of nutrition and performance-specific literature with current scientific data related to energy needs, assessment of body composition, strategies for weight change, nutrient and fluid needs, special nutrient needs during training and competition, the use of supplements , nutrition recommendations for vegetarian athletes and the roles and responsibilities of sports dietitians. Energy and macronutrients need especially carbohydrate and protein, must be met during times of high physical activity to maintain body weight, replenish glycogen stores, and provide adequate protein to build and repair tissue. Fat intake should be sufficient to provide the essential fatty acids and fat-soluble vitamins, as well as contribute energy for weight maintenance. Adequate food and fluid should be consumed before, during, and after exercise to help maintain blood glucose concentration during exercise, maximize exercise performance and improve recovery time. Athletes should be well hydrated before exercise and drink enough fluid during and after exercise to balance fluid losses. Sports beverages containing carbohydrates and electrolytes may be consumed before, during, and after exercise to help maintain blood glucose concentration, provide fuel for muscles, and decrease the risk of dehydration and hyponatremia. Vitamin and mineral supplements are not needed if adequate energy to maintain body weight is consumed from a variety of foods. However, athletes who restrict energy intake, use severe weight-loss practices, eliminate one or more food groups from their diet, or consume unbalanced diets with low micronutrient density, may require supplements. Because regulations specific to nutritional ergogenic aids are poorly enforced, they should be used with caution, and only after careful product evaluation for safety, efficacy, potency, and legality.

Should Pre-Weaning Calf Diets Include Forage?

The present review article aimed to update and address the biological consequences of forage supply to pre-weaned dairy calves. Early growth and development of a calf play a great role in lifelong performance of the animal. Comprehension of these stages is an important progress achieved in calf nutrition today. Health, milk-solid feed intake and rumen development are the most important factors related to calf growth in pre- and post-weaning periods. It is well understood that fermentation by-products of grain-based starter feeds are essential for increased growth and absorptive capacity of the rumen papillae. In pre-weaned calves, two major hypotheses exist regarding forage feeding. The first hypothesis describes that the rumen was not completely developed in pre-weaned calves and forage supply during this period might increase gut fill and hence, decrease starter intake. It is believed that depressed starter intake may limit energy intake and finally suppress calf growth rate. The second hypothesis indicates that rumen pH may decline as calf age and starter intake increases. Accordingly, forage supplementation into calf starter diets could prevent further rumen pH decline and subsequent negative consequences while improving starter intake and calf growth. Because research data regarding these hypotheses are controversial, there is no universally accepted standard for feeding calves with forage as a part of starter diets. Many factors, such as milk feeding method, grain, forage type and experimental conditions, could affect calf response to dietary forage. However, there is an evidence that limited consumption of forage may be beneficial on rumen health and behavior of calves consuming highly processed (pelleted or finely ground) starter feed in pre-weaning period.
 Keywords: Forage; Growth performance; Pre-weaned calf; Rumen development

Mechanisms underlying retardation of aging by dietary energy restriction.

Moderate restriction of dietary energy intake, referred to here as dietary restriction (DR), delays aging and extends lifespan in experimental animals compared with a diet of ad libitum feeding (AL) control animals. Basic knowledge of the mechanisms underlying the effects of DR could be applicable to extending the healthspan in humans. This review highlights the importance of forkhead box O (FoxO) transcription factors downstream of the growth hormone-insulin-like growth factor 1 signaling in the effects of DR. Our lifespan studies in mice with heterozygous Foxo1 or Foxo3 gene knockout indicated differential roles of FoxO1 and FoxO3 in the tumor-inhibiting and life-extending effects of DR. Subsequent studies suggested a critical role of FoxO3 in metabolic and mitochondrial bioenergetic adaptation to DR. Our studies also verified hypothalamic neuropeptide Y (Npy) as a vital neuropeptide showing pleiotropic and sexually dimorphic effects for extending the healthspan in the context of nutritional availability. Npy was necessary for DR to exert its effects in male and female mice; meanwhile, under AL conditions, the loss of Npy prevented obesity and insulin resistance only in female mice. Overnutrition disrupts FoxO- and Npy-associated metabolic and mitochondrial bioenergetic adaptive processes, causing the acceleration of aging and related diseases.

Effects of Metabolizable Energy Intake and Body-Weight Restriction on Layer Pullets: 1-Growth, Uniformity, and Efficiency

This study aimed to determine the effects of dietary energy and body-weight (BW) restriction on layer pullets’ growth, uniformity, and feed efficiency. Two experiments were conducted using a precision feeding (PF) system (Experiment 1) and a conventional feeding (CON) system (Experiment 2). Experiment 1 consisted of a 2 × 4 factorial arrangement (eight treatments) with two feed allocation (FA) levels: meal every visit (MEV) or restricted to the lower boundary of Lohmann Brown-Lite pullets; and three dietary metabolizable energy (ME) levels: Low, Standard (Std), and High (2600, 2800, and 3000 kcal/kg, respectively); the fourth treatment enabled birds to choose from the three diets (Choice). Experiment 2 consisted of a 2 × 3 factorial arrangement (six treatments): two FA levels (ad libitum or restricted) and three dietary ME levels (Low, Std, and High). In each experiment, BW, coefficient of variation (CV), average daily feed intake (ADFI), average daily metabolizable energy intake (MEI), and feed conversion ratio (FCR) were recorded. Diet ADFI preferences and feeding motivation were determined only in the PF experiment. ANOVA was conducted on each experiment with the two main effects as fixed factors (FA and dietary ME), and age or period as the sources of variation. Differences were reported at p ≤ 0.05. MEV (PF experiment) and ad libitum-fed (CON experiment) pullets had greater BW compared to restricted-fed pullets (p < 0.05). The lowest CV was observed in the restricted-fed pullets from the PF experiment (p < 0.05). ADFI was greater in pullets fed the Low ME diet in the PF experiment compared to all the other groups, and the lower the dietary ME, the greater the ADFI in the CON experiment (p < 0.05). Choice-feeding pullets preferred feed with greater ME content in the PF experiment (p < 0.05). The lower the dietary ME, the greater the FCR in the CON experiment (p < 0.05). Restricted-fed pullets had greater daily visits, and lower daily meals, meal size, and successful visits to the PF system (p < 0.05). In conclusion, the results of this trial indicated that lower dietary ME increased FCR and ADFI, whereas feed restriction decreased BW and increased feeding motivation. Future steps after this trial will include examining the effects of dietary energy and feed restriction on carcass composition and sexual maturation.

Bioactive Properties, Bioavailability Profiles, and Clinical Evidence of the Potential Benefits of Black Pepper (Piper nigrum) and Red Pepper (Capsicum annum) against Diverse Metabolic Complications.

The consumption of food-derived products, including the regular intake of pepper, is increasingly evaluated for its potential benefits in protecting against diverse metabolic complications. The current study made use of prominent electronic databases including PubMed, Google Scholar, and Scopus to retrieve clinical evidence linking the intake of black and red pepper with the amelioration of metabolic complications. The findings summarize evidence supporting the beneficial effects of black pepper (Piper nigrum L.), including its active ingredient, piperine, in improving blood lipid profiles, including reducing circulating levels of total cholesterol, low-density lipoprotein cholesterol, and triglycerides in overweight and obese individuals. The intake of piperine was also linked with enhanced antioxidant and anti-inflammatory properties by increasing serum levels of superoxide dismutase while reducing those of malonaldehyde and C-reactive protein in individuals with metabolic syndrome. Evidence summarized in the current review also indicates that red pepper (Capsicum annum), together with its active ingredient, capsaicin, could promote energy expenditure, including limiting energy intake, which is likely to contribute to reduced fat mass in overweight and obese individuals. Emerging clinical evidence also indicates that pepper may be beneficial in alleviating complications linked with other chronic conditions, including osteoarthritis, oropharyngeal dysphagia, digestion, hemodialysis, and neuromuscular fatigue. Notably, the beneficial effects of pepper or its active ingredients appear to be more pronounced when used in combination with other bioactive compounds. The current review also covers essential information on the metabolism and bioavailability profiles of both pepper species and their main active ingredients, which are all necessary to understand their potential beneficial effects against metabolic diseases.

Can you learn to starve yourself? Inducing food avoidance in the laboratory

The restriction of energy intake is a central and persistent symptom of anorexia nervosa. Recent models of the disorder suggest that food restrictions are learned avoidance behaviours, which are acquired and maintained by classical and operant conditioning. The present study aims to test this learning model of food restriction. It investigates whether introducing negative consequences for the intake of tasty high-calorie food and introducing positive consequences for its avoidance can create food avoidance, increase fear of food, and decrease eating desires in healthy individuals. 104 women were randomly assigned to an experimental or control condition and completed an appetitive conditioning and avoidance learning task. While the experimental condition received money after avoiding the tasty high-calorie food item and heard an aversive sound after not avoiding food intake, the control condition never received these consequences. In the extinction phase, reward and punishment discontinued for both conditions. We measured avoidance frequency, mouse movements, fear, eating desires and stimulus liking. Participants in the experimental condition avoided the food more often than controls and showed increased fear, reduced eating desires and less liking for cues associated with food intake. These results support the notion that food avoidance behaviours, reduced eating desires and fear of food can be learned via classical and operant conditioning. Conditioning paradigms might be a useful tool to study the development and maintenance of food restriction in anorexia nervosa.

The Association of Specific Dietary Patterns with Cardiometabolic Outcomes in Women with a History of Gestational Diabetes Mellitus: A Scoping Review

Gestational diabetes mellitus is associated with a significantly increased risk of later type 2 diabetes (T2DM) and cardiovascular disease (CVD). Post-natal interventions aim to reduce this risk by addressing diet and lifestyle factors and frequently focus on restricting energy or macronutrient intake. With increased interest in the role of complete dietary patterns in the prevention of cardiometabolic disease, we sought to evaluate what is known about the role of dietary patterns in reducing cardiometabolic risk in women with previous GDM. A systematic search was conducted to identify studies relating to dietary pattern and cardiometabolic parameters in women with a history of GDM. The search criteria returned 6014 individual studies. In total, 71 full texts were reviewed, with 24 studies included in the final review. Eleven individual dietary patterns were identified, with the Alternative Health Eating Index (AHEI), Mediterranean diet (MD), and low glycaemic index (GI) as the most commonly featured dietary patterns. Relevant reported outcomes included incident T2DM and glucose tolerance parameters, as well as several cardiovascular risk factors. Dietary patterns which have previously been extensively demonstrated to reduce the risk of cardiovascular and metabolic disorders in the general population, including AHEI, MD, and DASH, were found to be associated with a reduction in the incidence of T2DM, hypertension, and additional risk factors for cardiometabolic disease in women with a history of GDM. Notable gaps in the literature were identified, including the relationship between dietary patterns and incident CVD, as well as the relationship between a low GI diet and the development of T2DM in this population.

Spinal muscular atrophy and anorexia nervosa: a case report

BackgroundSpinal muscular atrophy (SMA) is an autosomal recessive condition affecting lower motor neurons causing progressive muscle atrophy. Anorexia nervosa (AN) is a psychiatric disorder characterised by intense fear of weight gain, restriction of energy intake, and preoccupation with body weight and shape. Low weight, gastrointestinal dysmotility, and respiratory infections are common in SMA but may mask AN. No paediatric cases of AN in SMA have been reported to date.Case presentationA 14-year-old female with SMA2 presented with 12 months of declining body weight to a nadir of 24.8 kg (BMI 11). This was initially attributed to medical complications including pneumonia and gastroenteritis, and chronic gut dysmotility associated with SMA. Despite almost 2 years of dietetic input and nutritional supplementation due to the weight plateauing from age 11, no significant restoration or gain was achieved. The Eating Disorder Examination-Questionnaire (EDE-Q) indicated a possible eating disorder and psychiatric evaluation confirmed AN.Initial management prioritised close medical monitoring and outpatient weight restoration on an oral meal plan. Skin fold anthropometric measurement was conducted to determine a minimum healthy weight. Individual psychological therapy and family sessions were undertaken. The patient developed major depression and a brief relapse with weight loss to 28 kg. Since then, the patient has maintained a weight of around 35 kg with stable mood.ConclusionsLow body weight, feeding issues, gastrointestinal dysmotility, and respiratory infections are common in SMA and diagnostic overshadowing can lead to delayed recognition of anorexia nervosa. Change to growth trajectory and prolonged weight loss should prompt consideration of comorbid psychiatric issues. Screening measures such as the EDE-Q and DASS may be helpful in this population. Close liaison between the neurogenetics and psychiatry teams is helpful. Skin fold anthropometry can assist in identifying a minimum healthy weight range.

Short-Term Moderate Energy Restriction Does Not Affect Indicators of Oxidative Stress and Genotoxicity in Humans

Restriction of energy intake (ER), without malnutrition of essential nutrients, has repeatedly been demonstrated to increase longevity in rodents. In the antioxidant theory of aging the lack of balance between the generation of free radicals and free radical scavenging was thought to be a main causal agent in the aging process. From this point of view the antiaging effect induced by ER might be due to the lower rate of free-radical production and related damage induced by a lower metabolic rate. The antiaging effects of ER might also occur in humans. This study explored the effects of a 10-week moderately energy-restricted diet (80% of habitual) in 24 non-obese middle-aged men (16 ER subjects, 8 controls) on resting metabolic rate (RMR) and indicators of the primary antioxidant defense system, oxidative stress and genotoxicity. RMR decreased significantly in both groups, even when adjustments were made for the change in body composition. The increase in blood vitamin C concentrations correlated with the increase in urinary 8-hydroxy-deoxyguanosine (80HdG) excretion. The change in urinary 80HdG excretion also correlated with the change in RMR per kg fat-free mass. No differences between groups were found for changes in indicators of genotoxicity, erythrocyte catalase, glutathione peroxidase and superoxide dismutase activity and in plasma vitamin E, A or β-carotene concentrations. We conclude that 10 weeks of moderate ER did not affect indicators of antioxidative capacity, oxidative stress and genotoxicity of humans. Since subjects were not in energy balance at the end of the study, no conclusions can be made with respect to long-term effects.

Rat Serum Osteocalcin Concentration Is Decreased by Restriction of Energy Intake

We studied the effects of energy restriction on serum osteocalcin concentration and bone formation rate in rats. The experiment was designed to achieve energy restriction by reducing the carbohydrate intake while providing identical quantities of protein, fat, vitamins and minerals. Energy intakes of three groups of post-weaning male rats were restricted by 20, 40 and 60% for 4 wk. Serum calclum, phosphorus, transthyretin, triiodothyronine (T3), thyroxine (T4), 1,25-dihydroxycholecalciferol, 25-hydroxycholecalciferol and immunoreactive parathyroid hormone (iPTH) concentrations were determined. Energy restriction (20, 40 and 60%) produced a significant and gradual drop of serum osteocalcin concentrations, although the serum concentrations of its key regulators, i.e., 1,25-dihydroxycholecalciferol and iPTH, were not significantly affected. On the contrary, serum concentrations of calcium, phosphorus, transthyretin, T3 and T4 were significantly lower in the energy-restricted groups. However, our results do not support their implication in the regulation of serum osteocalcin synthesis by energy intake. Serum osteocalcin concentration was positively correlated with bone mineral apposition (r = 0.50, P < 0.05) and bone mineralization (r = 0.50, P < 0.05) rates suggesting that its decrease resulted from a reduction of bone formation, and not from abnormal mineralization, because osteoid seam thickness was not modified. Energy intake seems to be an important determinant of serum osteocalcin concentration and bone formation; however, the exact mechanism underlying this regulation remains to be determined.

Effect of Intermittent Fasting on Glycaemic Control in Patients With Type 2 Diabetes Mellitus: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

Background: Type 2 diabetes mellitus (T2DM) is a severe public health issue notably impacting human life and health expenditure. It has been observed in literature that intermittent fasting (IF) addresses diabetes and its underlying cause, which benefits people with diabetes. Therefore, this study aimed to evaluate the effectiveness of IF treatment on glycaemic control in people with T2DM compared with control group. Methods: Systematic review and meta-analysis of interventional studies among patients with T2DM with glycated haemoglobin (HbA1c) as an outcome was performed. A comprehensive search of electronic databases, including PubMed, Embase and Google Scholar, for articles published before 24 April 2022, was done. Studies reporting 24 hours of complete fasting or intermittent restricted energy intake (feeding permitted for only 4-8 hours daily, with 16-20 hours of fasting) and reporting changes in HbA1c and fasting glucose levels were eligible. Meta-analysis was performed using Cochrane's Q statistic and the I2 statistical approach. Results: Eleven studies (13 arms) measuring the effect of IF on patients' HbA1c level were analysed. There was no statistically significant difference between IF and control groups (Standardized mean difference [SMD] -0.08, 95% confidence interval [CI] -0.20 to 0.04;p=0.19, I2=22%). Overall, seven studies on patients' fasting blood glucose were analysed, and the meta-analysis revealed no significant difference between the two groups i.e. IF and control groups (SMD 0.06, 95% CI -0.25 to 0.38;p=0.69, I2=76%). Conclusion: IF and usual diet pattern have no difference in terms of glycaemic control. Although, IF may be used as a preventative diet pattern in the pre-diabetic population, as it works well in the long-term to achieve controlled sugar levels. Study registration: The protocol of this study was registered in The International Prospective Register of Systematic Reviews (PROSPERO) with a registration number CRD42022328528.

Intermittent fasting increases growth differentiation factor 15 in females with overweight or obesity but not associated with food intake

Growth differentiation factor 15 (GDF15) increases with acute fast in animals, and high GDF15 reduces food intake in rodents. We explored whether GDF15 was altered following intermittent fasting (IF) versus caloric restriction (CR), and associations with energy intake. Females with obesity received all foods at 70% (IF70 and CR70) or 100% of energy requirements for 8 weeks. IF ate 2–9% less than provided on refeeding days, resulting in greater weight losses. GDF15 was increased 5% more in IF70 versus CR70, but not associated with energy intake. This rise in GDF15 is unlikely to explain restriction of energy intake during IF.

Rhamnose Displays an Anti-Obesity Effect Through Stimulation of Adipose Dopamine Receptors and Thermogenesis.

The imbalance between energy intake and energy expenditure leads to the prevalence of obesity worldwide. A strategy to simultaneously limit energy intake and promote energy expenditure would be an important new obesity treatment. Here, we identified rhamnose as a nonnutritive sweetener to promote adipose thermogenesis and energy expenditure. Rhamnose promotes cAMP production and PKA activation through dopamine receptor D1 in adipose tissue. As a result, rhamnose administration promotes UCP1-dependent thermogenesis and ameliorates obesity in mice. Thus, we have demonstrated a rhamnose-dopamine receptor D1-PKA axis critical for thermogenesis, and that rhamnose may have a role in therapeutic molecular diets against obesity.

Compliance of participants undergoing a ‘5-2’ intermittent fasting diet and impact on body weight

Intermittent fasting (IF) has grown in popularity as a weight loss tool, where caloric intake is fully/partially restricted on a recurring basis. This study aimed to assess compliance with IF fast-day calorie restriction and whether 5-2 IF leads to reduced overall energy intake, weight loss and compensatory increased energy intake on non-fast days. Participants completed diet diaries at baseline and 28 days post 5-2 IF in a repeated measures within-subjects design. 5-2 IF required restricted energy intake to 500kcal/day (women), 650kcal/day (men) on two 'fast' days/week whilst eating ad-libitum on other days. 52 participants were included (n=42 female; age 44±11.2yrs). Median weight loss after 28 days 5-2 IF was statistically significant (1.8 [-2 - 7.3 IQR=2.2]kg; 2.8 [-2.7-11.2 IQR=2.5]% p < 0.001). There was a significant reduction in total energy intake during 5-2 IF compared with pre-diet (median 1288.0 [IQR 423.8]kcal and median 1751.5 [IQR 505.3]kcal respectively, p<0.001). Carbohydrate, protein and fat consumption proportionately reduced during 5-2 IF. Participants had significantly higher energy intake (p<0.001) on non-fast days that followed a fast day (1928.4±711.9kcal) compared to non-fast days not following a fast day (1316.2±310.0kcal). 55.8% complied with fast day calorie restrictions. 5-2 IF was associated with significantly reduced energy intake, and weight loss over a 28-day period. Compliance rate was lower than most previous studies. Participants had significantly higher energy intake on non-fast days following fast days suggesting fasting may lead to over-compensation. Further research should investigate strategies to improve compliance and long-term sustainability of IF diets.

Low-cost thermoregulation of wild sloths revealed by heart rate and temperature loggers

Arboreal herbivores require large digestive tracts for leaf fermentation and detoxification; however, they must also have a low body mass that allows them to reach the foliage. The three-toed sloth, Bradypus tridactylus, experiences this trade-off, as leaves comprise 97.2% of its diet. Their calorie intake is extremely low owing to the low available caloric density of leaves and slow digestive processes related to leaf fibre fermentation and secondary compound detoxification. Sloths may require a high body temperature to assist fermentation; however, thermogenesis is energy-consuming. To investigate how sloths accomplish thermoregulation using marginal energy, we attached heart rate (HR) and temperature loggers to wild B. tridactylus individuals inhabiting the Amazon rainforest and recorded their HR and body surface temperature (Tskin). Tskin changed with ambient temperature (Ta) but was higher than Ta in 99.2% of cases. Increases in Tskin and HR did not coincide, suggesting that the increases were not caused by thermogenesis. Instead, they may passively increase Tskin by selecting warmer microhabitats and sunbathing. Consequently, 90.5% of Tskin were within 27.6–36.0 °C while the Ta fluctuated between 21.5 and 42.9 °C. This low-cost thermoregulation results in a low HR. In this study, the mean HR during observation was approximately 38.4% of the expected value based on the mammalian allometric relationship between body mass and HR. Thus, these properties may contribute to the low metabolic rates of sloths, alleviating their restricted energy intake.