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Background and Aim: Intermittent fasting (IF) has been demonstrated to enhance human health through several mechanisms. However, it is still unclear whether those health benefits are independent of caloric restriction (CR)-induced weight loss. This systematic review and meta-analysis aimed to compare isocaloric IF and CR regarding anthropometric measurements, adherence, metabolic profile, inflammatory biomarkers, and adipokines in adults and elderlies., Methods and Results: Comprehensive research was conducted usin four major databases including Embase, PubMed, Scopus, and Google Scholar without date restriction. Mean differences of the change from baseline ± change SD were calculated as the differences between IF and CR groups. Subgroup analysis was performed according to intervention duration (short-, medium-, and long-term). To determine the reliability of our findings, GRADE assessment was performed. As a result, 20 RCTs were included in this systematic review and meta-analysis. IF groups had significant reductions in fat mass (kg) (P = 0.006) and Interleukin-6 (P < 0.00001) in the short term and fat mass (%) (P = 0.0002), waist circumference (P = 0.005), fasting blood insulin (P < 0.00001) and HOMA-IR (P = 0.04) in the long term. CR groups had significantly lower hunger (P = 0.003), fatigue (P = 0.04), and TG (P = 0.03)., Conclusions: IF may be an effective alternative to CR but is not superior to CR in enhancing human health. Due to the low number of long-term studies, future studies should focus on conducting longitudinal randomized trials comparing IF and CR in different populations, age groups, and IF patterns., Competing Interests: Declaration of competing interest The author(s) have declared the absence of any potential conflicts of interest concerning the research, authorship, and/or publication of this article., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Time-restricted feeding (TRF) is a lifestyle intervention that aims to maintain a consistent daily cycle of feeding and fasting to support robust circadian rhythms. Recently, it has gained scientific, medical, and public attention due to its potential to enhance body composition, extend lifespan, and improve overall health, as well as induce autophagy and alleviate symptoms of diseases like cardiovascular diseases, type 2 diabetes, neurodegenerative diseases, cancer, and ischemic injury. However, there is still considerable debate on the primary factors that contribute to the health benefits of TRF. Despite not imposing strict limitations on calorie intake, TRF consistently led to reductions in calorie intake. Therefore, while some studies suggest that the health benefits of TRF are primarily due to caloric restriction (CR), others argue that the key advantages of TRF arise not only from CR but also from factors like the duration of fasting, the timing of the feeding period, and alignment with circadian rhythms. To elucidate the roles and mechanisms of TRF beyond CR, this review incorporates TRF studies that did not use CR, as well as TRF studies with equivalent energy intake to CR, which addresses the previous lack of comprehensive research on TRF without CR and provides a framework for future research directions., (© The Author(s) 2024. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Body composition and body fat distribution are important predictors of cardiometabolic diseases. The etiology of cardiometabolic diseases is heterogenous, and partly driven by inter-individual differences in tissue-specific insulin sensitivity., Objectives: To investigate (1) the associations between body composition and whole-body, liver and muscle insulin sensitivity, and (2) changes in body composition and insulin sensitivity and their relationship after a 12-week isocaloric diet high in mono-unsaturated fatty acids (HMUFA) or a low-fat, high-protein, high-fiber (LFHP) diet., Methods: This subcohort analysis of the PERSON study includes 93 individuals (53% women, BMI 25-40 kg/m2, 40-75 years) who participated in this randomized intervention study. At baseline and after 12 weeks of following the LFHP, or HMUFA diet, we performed a 7-point oral glucose tolerance test to assess whole-body, liver, and muscle insulin sensitivity, and whole-body magnetic resonance imaging to determine body composition and body fat distribution. Both diets are within the guidelines of healthy nutrition., Results: At baseline, liver fat content was associated with worse liver insulin sensitivity (β [95%CI]; 0.12 [0.01; 0.22]). Only in women, thigh muscle fat content was inversely related to muscle insulin sensitivity (-0.27 [-0.48; -0.05]). Visceral adipose tissue (VAT) was inversely associated with whole-body, liver, and muscle insulin sensitivity. Both diets decreased VAT, abdominal subcutaneous adipose tissue (aSAT), and liver fat, but not whole-body and tissue-specific insulin sensitivity with no differences between diets. Waist circumference, however, decreased more following the LFHP diet as compared to the HMUFA diet (-3.0 vs. -0.5 cm, respectively). After the LFHP but not HMUFA diet, improvements in body composition were positively associated with improvements in whole-body and liver insulin sensitivity., Conclusions: Liver and muscle insulin sensitivity are distinctly associated with liver and muscle fat accumulation. Although both LFHP and HMUFA diets improved in body fat, VAT, aSAT, and liver fat, only LFHP-induced improvements in body composition are associated with improved insulin sensitivity., Trial Registration: NCT03708419 (clinicaltrials.gov)., (© 2024. The Author(s).)

A ketogenic diet (KD) is known to have beneficial health effects. Various types of KD interventions have been applied to manage metabolic syndrome based on modification of diet parameters such as duration of intervention, macronutrient components, and total calories. Nevertheless, the beneficial health impact of isocaloric KD is largely unknown, especially in healthy subjects. The present study investigated the acute effects of a 3-day isocaloric KD. In this non-randomized intervention study, we recruited 15 healthy volunteers aged 24-38 years (7 men and 8 women) and placed them on an isocaloric KD restricting intake of carbohydrates but not energy (75% fat, 20% protein, 5% carbohydrate) for 3 days. Biochemical profiles and laboratory measurements were performed. Peripheral blood monocular cells were cultured, and measured cell stimulated cytokines. After short-term isocaloric KD, subjects lost body weight and serum free fatty acid levels were increased. These results accompanied elevated serum β-hydroxybutyrate (BHB) concentration and fibroblast growth factor 21 (FGF21) levels and improved insulin sensitivity. Regarding the direct effect of BHB on inflammasome activation, interleukin-1β (IL-1β) and tumor necrosis factor-α secretion in response to adenosine triphosphate or palmitate stimulation in human macrophages decreased significantly after isocaloric KD. In ex-vivo experiments with macrophages, both FGF21 and BHB further reduced IL-1β secretion compared to either BHB or FGF21 alone. The inhibitory effect of FGF21 on IL-1β secretion was blunted with bafilomycin treatment, which blocked autophagy flux. In conclusion, isocaloric KD for 3 days is a promising approach to improve metabolic and inflammatory status., Clinical Trial Registration: clinicaltrials.gov (NCT02964572)., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Kim, Kim, Cho, Lee, Kim, Kim, Choi, Kim, Yu, Lee, Kang, Cha, Lee, Cho, Jeon and Lee.)

Excess nutrition causes loss of olfactory sensory neurons (OSNs) and reduces odour discrimination and odour perception in mice. To separate diet-induced obesity from the consumption of dietary fat, we designed pair-feeding experiments whereby mice were maintained on isocaloric diets for 5 months, which prevented increased fat storage. To test our hypothesis that adiposity was not a prerequisite for loss of OSNs and bulbar projections, we used male and female mice with an odorant receptor-linked genetic reporter (M72tauLacZ; Olfr160) to visualize neural circuitry changes resulting from elevated fat in the diet. Simultaneously we monitored glucose clearance (diagnostic for prediabetes), body fat deposition, ingestive behaviours, select inflammatory markers and energy metabolism. Axonal projections to defined olfactory glomeruli were visualized in whole-mount brains, and the number of OSNs was manually counted across whole olfactory epithelia. After being pair fed a moderately high-fat (MHF) diet, mice of both sexes had body weight, adipose deposits, energy expenditure, respiratory exchange ratios and locomotor activity that were unchanged from control-fed mice. Despite this, they were still found to lose OSNs and associated bulbar projections. Even with unchanged adipocyte storage, pair-fed animals had an elevation in TNF cytokines and an intermediate ability for glucose clearance. Albeit improving health metrics, access to voluntary running while consuming an ad libitum fatty diet still precipitated a loss of OSNs and associated axonal projections for male mice. Our results support that long-term macronutrient imbalance can drive anatomical loss in the olfactory system regardless of total energy expenditure. KEY POINTS: Obesity can disrupt the structure and function of organ systems, including the olfactory system that is important for food selection and satiety. We designed dietary treatments in mice such that mice received fat, but the total calories provided were the same as in control diets so that they would not gain weight or increase adipose tissue. Mice that were not obese but consumed isocaloric fatty diets still lost olfactory neuronal circuits, had fewer numbers of olfactory neurons, had an elevation in inflammatory signals and had an intermediate ability to clear glucose (prediabetes). Mice were allowed access to running wheels while consuming fatty diets, yet still lost olfactory structures. We conclude that a long-term imbalance in nutrition that favours fat in the diet disrupts the olfactory system of mice in the absence of obesity., (© 2021 The Authors. The Journal of Physiology © 2021 The Physiological Society.)

Obesity impairs both macro- and microvascular endothelial function due to decreased bioavailability of nitric oxide. Current evidence on the effect of low-carbohydrate (LC) diet on endothelial function is conflicting and confounded by the provision of caloric restriction (CR). We tested the hypothesis that LC without CR diet, but not LC with CR diet, would improve macro- and microvascular endothelial function in women with obesity. Twenty-one healthy women with obesity (age: 33 ± 2 years, body mass index: 33.0 ± 0.6 kg/m 2 ; mean ± SEM) were randomly assigned to receive either a LC diet (~10% carbohydrate calories) with CR ( n = 12; 500 calorie/day deficit) or a LC diet without CR ( n = 9) and completed the 6-week diet intervention. After the intervention, macrovascular endothelial function, measured as brachial artery flow-mediated dilation did not change (7.3 ± 0.9% to 8.0 ± 1.1%, p = 0.7). On the other hand, following the LC diet intervention, regardless of CR, blocking nitric oxide production decreased microvascular endothelial function, measured by arteriolar flow-induced dilation ( p ≤ 0.02 for both diets) and the magnitude was more than baseline ( p ≤ 0.04). These data suggest improved NO contributions following the intervention. In conclusion, a 6-week LC diet, regardless of CR, may improve microvascular, but not macrovascular endothelial function, via increasing bioavailability of nitric oxide in women with obesity., Competing Interests: The authors declare no conflict of interest. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health and the American Heart Association.

Obesity is associated with microvascular dysfunction. While low-fat diet improves cardiovascular risk, its contributions on microvascular function, independent of weight loss, is unknown. We tested the hypothesis that nitric oxide (NO)-dependent vasodilation in microvessels is improved by low-fat diets designed for weight loss (LFWL) compared to low-fat weight maintenance (LFWM) diet. Obese adults were randomly assigned to either a LFWL diet ( n = 11) or LFWM diet ( n = 10) for six weeks. Microvessels were obtained from gluteal subcutaneous fat biopsies before and after the intervention for vascular reactivity measurements to acetylcholine (Ach) and flow, with and without L-NAME or indomethacin. Vascular and serum NO and C-reactive protein (CRP) were also measured. LFWL diet increased flow-induced (FID) and ACh-induced dilation (AChID); an effect that was inhibited by L-NAME. Conversely, LFWM diet did not affect FID or AChID. Indomethacin improved FID and AChID in the baseline and this effect was minimized in response to both diets. Serum NO or CRP did not change in response to either diet. In conclusion, LFWL diet improves microvascular reactivity compared to LFWM diet and increased vascular NO contribution to the improved microvascular dilation. These data suggest that weight reduction on low fat diet is critical for microvascular health.

Daily torpor is a physiological adaptation in mammals and birds characterized by a controlled reduction of metabolic rate and body temperature during the resting phase of circadian rhythms. In laboratory mice, daily torpor is induced by dietary caloric restriction. However, it is not known which nutrients are related to daily torpor expression. To determine whether dietary protein is a key factor in inducing daily torpor in mice, we fed mice a protein-restricted (PR) diet that included only one-quarter of the amount of protein but the same caloric level as a control (C) diet. We assigned six non-pregnant female ICR mice to each group and recorded their body weights and core body temperatures for 4 weeks. Body weights in the C group increased, but those in the PR group remained steady or decreased. Mice in both groups did not show daily torpor, but most mice in a food-restricted group (n=6) supplied with 80% of the calories given to the C group exhibited decreased body weights and frequently displayed daily torpor. This suggests that protein restriction is not a trigger of daily torpor; torpid animals can conserve their internal energy, but torpor may not play a significant role in conserving internal protein. Thus, opportunistic daily torpor in mice may function in energy conservation rather than protein saving.

Aim: The growth promoting effect of the blue-green filamentous alga Spirulina platensis (SP) was observed on meat type Japanese quail with antibiotic growth promoter alternative and immune enhancing power., Materials and Methods: This study was conducted on 180 Japanese quail chicks for 4 weeks to find out the effect of diet type (vegetarian protein diet [VPD] and fish meal protein diet [FMPD])- Spirulina dose interaction (1 or 2 g/kg diet) on growth performance, gut microbiota, and sensory meat quality of growing Japanese quails (1-5 weeks old)., Results: Data revealed improvement (p<0.05) of weight gain, feed conversion ratio and European efficiency index due to 1, 2 g (SP)/kg VPD, and 2 g (SP)/kg FMPD, respectively. There was a significant decrease of ileum mean pH value by 1 g (SP)/kg VPD. Concerning gut microbiota, there was a trend toward an increase in Lactobacilli count in both 1; 2 g (SP)/kg VPD and 2 g (SP)/kg FMPD. It was concluded that 1 or 2 g (SP)/kg vegetarian diet may enhance parameters of performance without obvious effect on both meat quality and gut microbiota. Moreover, 1 and/or 2 g (SP) may not be invited to share fish meal based diet for growing Japanese quails., Conclusion: Using of SP will support the profitable production of Japanese quails fed vegetable protein diet.

Background: Aerobic interval training (IT) seems to be superior to continuous training (CT) in improving exercise capacity (peak oxygen uptake (VO2)) in coronary artery disease (CAD) patients in some, but not in all studies. Based on theoretical calculations, these comparative studies stated that the energy expenditure (EE) of both programmes is similar. To date, the caloricity of both programmes has never been objectively measured. Therefore, our aim was to objectively measure the EE of the IT and CT programmes described in the protocol of the SAINTEX-CAD study (based on Wisloff et al.; ITw and CTw), and the actually performed training intensities in the SAINTEX-CAD study by Conraads et al. (ITc and CTc)., Methods: Following a two-week run-in period with three IT and three CT training sessions, 18 male CAD patients (mean age 62.4 ± 6.1 years) performed four training sessions in random order on the cycle ergometer: an ITw, CTw, ITc and CTc test session. The EE was assessed by indirect calorimetry using gas exchange measurements obtained with the Oxycon mobile., Results: We found a higher EE for CTc compared to ITc (352 ± 90.8 kcal versus 269 ± 70.7 kcal; p = 0.026), while CTw and ITw seemed to be isocaloric (317 ± 85.2 kcal versus 273 ± 65.3 kcal; p = 0.42). Higher lactate levels were reached after IT sessions (ITw 5.42 ± 1.42 mmol/l, ITc 5.05 ± 1.38 mmol/l) compared to CT sessions (CTw 2.45 ± 1.04 mmol/l, CTc 3.41 ± 1.44 mmol/l) (p < 0.01). Lactate levels increased above baseline levels (1.91 ± 0.34 mmol/l) except for the CTw session., Conclusion: CTc expended significantly more energy compared to ITc, showing that the programmes used in the SAINTEX-CAD study were not isocaloric. In contrast, isocaloricity was met for CTw and ITw., (© The European Society of Cardiology 2016.)