Acute and Chronic Effects of Exercise on Appetite, Energy Intake, and Appetite-Related Hormones: The Modulating Effect of Adiposity, Sex, and Habitual Physical Activity

Effects of a 12-Week Diet versus Diet plus Aerobic and Resistance Exercise Program on Acylated and Desacylated Ghrelin, and Ghrelin O-Acyltransferase in Adolescent Girls with Obesity

This study investigated the effects of a 12-week diet versus diet plus aerobic and resistance exercise programme on acylated ghrelin (AG), desacylated ghrelin (DAG), and ghrelin O-acyltransferase (GOAT) concentrations in girls with obesity. We randomised 30 adolescents with obesity to a 12-week aerobic and resistance exercise group (EG) or a control group (CG). At baseline and at 4, 8, and 12 weeks, we measured their body composition, lipid profile, glucose, AG, DAG, and GOAT concentrations. In the EG, the body fat percentage decreased by 2.37% and was significantly lower than that in the CG. The DAG concentrations significantly increased by 48.3% and 27.4% in the EG and CG, respectively. At 4, 8, and 12 weeks, DAG concentrations were significantly higher in the EG than in the CG. AG concentrations were higher at week 12 than at baseline in both groups. In both groups, the GOAT concentrations increased at weeks 8 and 12; however, no between-group differences were observed in the changes in GOAT concentrations. This study showed increased DAG concentrations and non-significant changes in AG and GOAT concentrations after a 12-week aerobic and resistance exercise programme in girls with obesity. These findings suggest that an aerobic and resistance exercise programme influences appetite-regulating hormones, mainly through changes in DAG concentrations.

Exercise increases NPY/AgRP and TH neuron activity in the hypothalamus of female mice

Recent evidence identifies a potent role for aerobic exercise to modulate the activity of hypothalamic neurons related to appetite; however, these studies have been primarily performed in male rodents. Since females have markedly different neuronal mechanisms regulating food intake, the current study aimed to determine the effects of acute treadmill exercise on hypothalamic neuron populations involved in regulating appetite in female mice. Mature, untrained female mice were exposed to acute sedentary, low- (10 m/min), moderate- (14 m/min), and high (18 m/min)-intensity treadmill exercise in a randomized crossover design. Mice were fasted 10 h before exercise, and food intake was monitored for 48 h after bouts. Immunohistochemical detection of cFOS was performed 3 h post-exercise to determine the changes in hypothalamic neuropeptide Y (NPY)/agouti-related peptide (AgRP), pro-opiomelanocortin (POMC), tyrosine hydroxylase (TH), and SIM1-expressing neuron activity concurrent with the changes in food intake. Additionally, stains for pSTAT3tyr705 and pERKthr202/tyr204 were performed to detect exercise-mediated changes in intracellular signaling. Briefly, moderate- and high-intensity exercises increased 24-h food intake by 5.9 and 19%, respectively, while low-intensity exercise had no effects. Furthermore, increases in NPY/AgRPARC, SIM1PVN, and TH neuron activity were observed 3 h after high-intensity exercise, with no effects on POMCARC neurons. While no effects of exercise on pERKthr202/tyr204 were observed, pSTAT3tyr705 was elevated specifically in NPY/AgRP neurons 3 h post-exercise. Overall, aerobic exercise increased the activity of several appetite-stimulating neuron populations in the hypothalamus of female mice, which may provide insight into previously reported sexual dimorphisms in post-exercise feeding.

Skipping breakfast and excess weight among young people: the moderator role of moderate-to-vigorous physical activity

The present study aimed to test whether the daily minutes of moderate-to-vigorous physical activity (MVPA) engaged moderate the relationship between breakfast status and excess weight (i.e., overweight and/or obesity) in a Spanish sample of young people. A cross-sectional study involving a total sample of 2890 Spanish schoolchildren (46% girls) aged 6-17 years (M = 12.3 ± 2.6) was conducted. To determine the habit of having breakfast, a dichotomous item about breakfast status (yes/no) from the Mediterranean Diet Quality Index for children and teenagers (KIDMED) was used. Physical Activity Questionnaire for Older Children and the Physical Activity Questionnaire for Adolescents were fulfilled to offer an estimation of the minutes of MVPA that individuals had in the last seven days. Body mass index (BMI) was converted into z-scores and, therefore, excess weight status (i.e., overweight and/or obesity) was established according to World Health Organization criteria for sex and age. Skipping breakfast was positively related with BMI (z-score) and excess weight. Moderation analyses suggested that daily MVPA minutes moderated the association between skipping breakfast and BMI (boys: β =  - 0.175; girls: β =  - 0.073) or the excess weight (boys: OR = 1.10; CI 95%, 1.02 to 1.07; girls: OR = 1.14; CI 95%, 1.04 to 1.24), meaning that physical activity of sufficient intensity seems to reduce the effect of skipping breakfast on the body weight status of young people.

CONCLUSION

Our results indicate that promotion of having breakfast should be accompanied by daily MVPA, as young participants who have breakfast and with higher daily MVPA seem to be more likely to have no excess weight.

WHAT IS KNOWN

• Some of the well-studied factors associated with childhood obesity have been skipping breakfast and insufficient physical activity. • Some studies have pointed out the association between having breakfast and both body mass index and physical activity level, in isolation.

WHAT IS NEW

• Daily minutes of moderate-to-vigorous physical activity moderate the association between skipping breakfast and excess weight. • Breakfast promotion as a healthy eating habit should be accompanied by increases in moderate-to-vigorous physical activity, since participants who have breakfast and with higher moderate-to-vigorous physical activity seem to be more likely to have no excess weight.

The Effects of Exercise on Appetite in Older Adults: A Systematic Review and Meta-Analysis

Background: The effect of physical activity and exercise on hunger and satiety has been well-studied in younger adults, but the influence of aging is less understood. While some evidence suggests that acute bouts of exercise induce a compensatory eating drive, long-term activity may improve satiety sensitivity. The objective of this study was to investigate the effects of exercise on appetite in older adults.

Methods: We systematically reviewed available literature investigating the effect of exercise on appetite in older adults adults (CRD42020208953). PubMed, PsycINFO, Academic Search Complete, the Sports Medicine & Education Index, and Web of Science, were searched for peer-reviewed articles published in English with no date restriction. Included studies implemented a primary exercise or physical activity intervention with a control group, on a generally healthy population ≥60 years of age. Selected studies included at least one appetite outcome. Risk of bias was assessed using the 11-point Physiotherapy Evidence Database (PEDro) tool. Standardized mean difference summary statistics (Hedge's g effect sizes) and 95% confidence intervals were reported.

Results: We identified 15 reports (13 studies) which met all inclusion criteria (5 resistance training, 3 aerobic, 6 mixed modalities). Studies included 443 participants (Age = 68.9 ± 5.2, 82.3% female) and had generally “good” bias scores (PEDro = 6.4 ± 0.88). Random effects meta-analyses revealed that the exercising group showed statistically significant reductions in glucose [SMD = −0.34 (95% CI: −0.67, −0.02), p < 0.05, PEDro =6.4 ± 0.45] and leptin [SMD = −0.92 (95% CI: −1.28, −0.57), p < 0.00001, PEDro = 6.2 ± 0.75].

Discussion: This systematic review revealed that exercise and physical activity may modulate resting hunger and satiety in older adults. Decreases in fasting leptin and glucose hormones suggest that exercise promotes satiety sensitivity in adults aged 60+. This review highlights that engaging in exercise and activity programs may provide a meaningful avenue for improving chronic and functional disease burden in later life by promoting appetite control and balanced energy intake. Recommendations for future research include investigations of appetite in response to varied exercise modalities within more diverse and representative samples of older adults.

Post-exercise energy intake: do the intensity and mode of exercise matter? A systematic review and meta-analysis comparing high-intensity interval with moderate-intensity continuous protocols

The present systematic review and meta-analysis aimed to compare the impact of exercise intensity and mode (high-intensity interval exercise-HIIE or sprint interval exercise-SIE versus moderate-intensity continuous exercise-MICE) on post-exercise ad libitum energy intake. The studies were required to have at least two exercise conditions (HIIE or SIE vs MICE). Overall, 642 manuscripts were initially identified and 17 met the eligibility criteria. The random effect meta-analysis did not reveal differences for absolute energy intake (28 pairwise comparisons) between HIIE (p = 0.54; 95% Confidence Interval - CI: -0.14 to 0.26; 22 pairwise comparisons) or SIE (p = 0.08; 95% CI -0.65 to 0.03; 6 pairwise comparisons) versus MICE, neither for relative energy intake (p = 0.97; 95% CI: -0.35 to 0.10 for HIIE; p = 0.28; 95% CI: -1.03 to 0.06 for SIE) with five and one pairwise comparisons, respectively. Subgroup analyses for methods to evaluate ad libitum energy intake, body mass, sex, volume, and timing of exercise were non-significant. Inspecting each study, two pairwise comparisons reported lower post-exercise absolute energy intake in HIIE compared to control (CRTL), and three pairwise comparisons reported lower absolute energy intake after SIE compared to MICE. None pairwise comparison reported differences between protocols (HIIE or SIE versus MICE) for relative energy intake. In conclusion, the meta-analysis did not show differences between protocols for absolute and relative energy intake; five pairwise comparisons from 28 demonstrated lower absolute energy intake in HIIE or SIE compared to CRTL or MICE. Further studies are needed to address the key relevant variables in which exercise intensity and mode may impact energy intake.

What Is the Impact of Energy Expenditure on Energy Intake?

Coupling energy intake (EI) to increases in energy expenditure (EE) may be adaptively, compensatorily, or maladaptively leading to weight gain. This narrative review examines if functioning of the homeostatic responses depends on the type of physiological perturbations in EE (e.g., due to exercise, sleep, temperature, or growth), or if it is influenced by protein intake, or the extent, duration, timing, and frequency of EE. As different measures to increase EE could convey discrepant neuronal or humoral signals that help to control food intake, the coupling of EI to EE could be tight or loose, which implies that some ways to increase EE may have advantages for body weight regulation. Exercise, physical activity, heat exposure, and a high protein intake favor weight loss, whereas an increase in EE due to cold exposure or sleep loss likely contributes to an overcompensation of EI, especially in vulnerable thrifty phenotypes, as well as under obesogenic environmental conditions, such as energy dense high fat—high carbohydrate diets. Irrespective of the type of EE, transient elevations in the metabolic rate seem to be general risk factors for weight gain, because a subsequent decrease in energy requirement is not compensated by an adequate adaptation of appetite and EI.

Examining the Role of Exercise Timing in Weight Management: A Review

Many adults cite exercise as a primary strategy for losing weight, yet exercise alone is modestly effective for weight loss and results in variable weight loss responses. It is possible that some of the variability in weight loss may be explained by the time of day that exercise is performed. Few studies have directly compared the effects of exercise performed at different times of the day (i. e., morning versus evening exercise). Results from these existing studies are mixed with some studies demonstrating superior weight and fat mass loss from morning exercise, while other studies have found that evening exercise may be better for weight management. Exercise timing may alter modifiable lifestyle behaviors involved in weight management, such as non-exercise physical activity, energy intake, and sleep. The purpose of this review is to summarize evidence for and against time-of-day dependent effects of exercise on weight management. Although limited, we also review studies that have examined the effect of exercise timing on other lifestyle behaviors linked to body weight regulation. While exercise at any time of day is beneficial for health, understanding whether there is an optimal time of day to exercise may advance personalized treatment paradigms for weight management.

Effect of Aerobic Exercise-induced Weight Loss on the Components of Daily Energy Expenditure

INTRODUCTION

Exercise usually results in less weight loss than expected. This suggests increased energy intake and/or deceased expenditure counteract the energy deficit induced by exercise. The aim of this study was to evaluate changes in components of daily energy expenditure (doubly labeled water and room calorimetry) after 24 wk of exercise training with two doses of aerobic exercise.

METHODS

This was an ancillary study in 42 (29 women, 13 men) sedentary, middle-age (47.8 ± 12.5 yr) individuals with obesity (35 ± 3.7 kg·m-2) enrolled in the Examination of Mechanisms of Exercise-induced Weight Compensation study. Subjects were randomized to three groups: healthy living control group (n = 13), aerobic exercise that expended 8 kcal·kg-1 of body weight per week (8 KKW, n = 14), or aerobic exercise that expended 20 kcal per kilogram of weight per week (20 KKW, n = 15). Total daily energy expenditure (TDEE) was measured in free-living condition by doubly labeled water and in sedentary conditions in a metabolic chamber over 24 h (24EE). Energy intake was calculated over 14 d from TDEE before and after the intervention using the intake-balance method.

RESULTS

Significant weight loss occurred with 20 KKW (-2.1 ± 0.7 kg, P = 0.04) but was only half of expected. In the 20 KKW group free-living TDEE increased by ~4% (P = 0.03), which is attributed to the increased exercise energy expenditure (P = 0.001), while 24EE in the chamber decreased by ~4% (P = 0.04). Aerobic exercise at 8 KKW did not induce weight change, and there was no significant change in any component of EE. There was no significant change in energy intake for any group (P = 0.53).

CONCLUSIONS

Structured aerobic exercise at a dose of 20 KKW produced less weight loss than expected possibly due to behavioral adaptations leading to reduced 24EE in a metabolic chamber without any change in energy intake.

Effects of Acute Heat and Cold Exposures at Rest or during Exercise on Subsequent Energy Intake: A Systematic Review and Meta-Analysis

The objective of this meta-analysis was to assess the effect of acute heat/cold exposure on subsequent energy intake (EI) in adults. We searched the following sources for publications on this topic: PubMed, Ovid Medline, Science Direct and SPORTDiscus. The eligibility criteria for study selection were: randomized controlled trials performed in adults (169 men and 30 women; 20–52 years old) comparing EI at one or more meals taken ad libitum, during and/or after exposure to heat/cold and thermoneutral conditions. One of several exercise sessions could be realized before or during thermal exposures. Two of the thirteen studies included examined the effect of heat (one during exercise and one during exercise and at rest), eight investigated the effect of cold (six during exercise and two at rest), and three the effect of both heat and cold (two during exercise and one at rest). The meta-analysis revealed a small increase in EI in cold conditions (g = 0.44; p = 0.019) and a small decrease in hot conditions (g = −0.39, p = 0.022) for exposure during both rest and exercise. Exposures to heat and cold altered EI in opposite ways, with heat decreasing EI and cold increasing it. The effect of exercise remains unclear.

Changes in Adolescents' Dietary Intake Following the Initiation of an 8-Week Exercise Program

Purpose: To assess changes in dietary intake of adolescents following an 8-week aerobic exercise program.Methods: Twenty-six adolescents (14-18 years) participated in an 8-week aerobic exercise program on cycle ergometer at their high school in Quebec, Canada. Twenty-four hour recalls were collected pre- and post-intervention. A two-way repeated measures ANOVA and paired sample t-tests were used to assess differences in energy and dietary intake parameters (food quantity, diet quality, eating patterns) between pre- and postintervention.Results: A decrease in total daily energy intake (-287.8 kcal, P = 0.007), in meal size at lunch (-110.1 g, P = 0.02) and dinner (-143.7 g, P = 0.03), in food density at breakfast (-1.8 kcal/g, P = 0.04), in daily carbohydrate intake (-56.1 g, P = 0.005), and in percentage of energy intake consumed at school (-5.1%, P = 0.04) were observed following initiation of an aerobic exercise program. No change in healthy eating index scores or percentage of energy from processed foods was observed.Conclusions: Changes in energy intake, food quantity, and eating pattern but not diet quality (Healthy Eating Index or food processing scores) were observed following the initiation of an aerobic exercise program. Nutrition interventions may be needed, in addition to an exercise program, to target diet quality and promote healthy eating habits in adolescents.

Dietary Intake and Energy Expenditure in Breast Cancer Survivors: A Review

Many breast cancer survivors (BCS) gain fat mass and lose fat-free mass during treatment (chemotherapy, radiation, surgery) and estrogen suppression therapy, which increases the risk of developing comorbidities. Whether these body composition alterations are a result of changes in dietary intake, energy expenditure, or both is unclear. Thus, we reviewed studies that have measured components of energy balance in BCS who have completed treatment. Longitudinal studies suggest that BCS reduce self-reported energy intake and increase fruit and vegetable consumption. Although some evidence suggests that resting metabolic rate is higher in BCS than in age-matched controls, no study has measured total daily energy expenditure (TDEE) in this population. Whether physical activity levels are altered in BCS is unclear, but evidence suggests that light-intensity physical activity is lower in BCS compared to age-matched controls. We also discuss the mechanisms through which estrogen suppression may impact energy balance and develop a theoretical framework of dietary intake and TDEE interactions in BCS. Preclinical and human experimental studies indicate that estrogen suppression likely elicits increased energy intake and decreased TDEE, although this has not been systematically investigated in BCS specifically. Estrogen suppression may modulate energy balance via alterations in appetite, fat-free mass, resting metabolic rate, and physical activity. There are several potential areas for future mechanistic energetic research in BCS (e.g., characterizing predictors of intervention response, appetite, dynamic changes in energy balance, and differences in cancer sub-types) that would ultimately support the development of more targeted and personalized behavioral interventions.

Is Energy Expenditure or Physical Activity Considered When Energy Intake Is Measured? A Scoping Review 1975-2015

The health-transitions humans have delivered during the 20th Century associated with the nutrition is that from undernutrition to obesity, which perseveres in the current years of the 21st Century. Energy intake (EI) is a contributing factor and therefore a fascination in nutritional sciences. However, energy expenditure (EE) has not been usually considered as a conjoint factor. Thus, this study aimed to review if studies on adults consider data on dietary intake, specifically EI, and included data on EE and physical activity (PA). A search of MEDLINE from 1975 to December 2015 was managed. Our scoping review consisted of keywords related to EI, dietary allowances, and nutritional requirements. From 2229 acknowledged articles, 698 articles were finally taken fulfilling inclusion and quality criteria. A total of 2,081,824 adults (53.7% females) were involved, and most studies had been conducted in EEUU (241), Canada (42), Australia (30), Japan (32), and Brazil (14). In Europe, apart from UK (64), the Netherlands (31) and France (26) led the classification, followed by Sweden (18), Denmark (17), and France (26). Mediterranean countries are represented with 27 studies. A total of 76.4% did not include EE and 93.1% did not include PA. Only 23.6% of the studies contained both EI and EE. A large methodological diversity was perceived, with more than 14 different methods regarding EI, and more than 10 for EE. PA was only analyzed in scarce articles, and scarcely considered for interpretation of data and conclusions. Moreover, PA was often measured by subjective questionnaires. Dietary surveys show a large diversity regarding methodology, which makes comparability of studies difficult. EE and PA are missing in around 80% of studies or are not included in the interpretation of results. Conclusions regarding EI or diet adequacy in adults should not be taken without analyzing EE and PA.

Perceptions of appetite do not match hormonal measures of appetite in trained competitive cyclists and triathletes following a ketogenic diet compared to a high-carbohydrate or habitual diet: A randomized crossover trial

Endurance athletes may implement rigid dietary strategies, such as the ketogenic diet (KD), to improve performance. The effect of the KD on appetite remains unclear in endurance athletes. This study analyzed the effects of a KD, a high-carbohydrate diet (HCD), and habitual diet (HD) on objective and subjective measures of appetite in trained cyclists and triathletes, and hypothesized that the KD would result in greater objective and subjective appetite suppression. Six participants consumed the KD and HCD for 2-weeks each, in a random order, following their HD. Fasting appetite measures were collected after 2-weeks on each diet. Postprandial appetite measures were collected following consumption of a ketogenic meal after the KD, high-carbohydrate meal after the HCD, and standard American/Western meal after the HD. Fasting total ghrelin (GHR) was lower and glucagon-like peptide-1 (GLP-1) and hunger were higher following the KD versus HD and HCD. Fasting insulin was not different. Mixed-effects model repeated measures analysis and effect sizes and 95% confidence intervals showed that postprandial GHR and insulin were lower and GLP-1 was higher following the ketogenic versus the standard and high-carbohydrate meals. Postprandial appetite ratings were not different across test meals. In conclusion, both fasting and postprandial concentrations of GHR were lower and GLP-1 were higher following the KD than the HC and HD, and postprandial insulin was lower on the KD. Subjective ratings of appetite did not correspond with the objective measures of appetite in trained competitive endurance athlete. More research is needed to confirm our findings.

Associations of apelin, leptin, irisin, ghrelin, insulin, glucose levels, and lipid parameters with physical activity during eight weeks of regular exercise training

OBJECTIVES

This study aims to evaluate the effects of 8 weeks of basketball training on apelin, leptin, irisin, ghrelin, insulin, glucose, and blood lipids among basketball players.

METHODS

The exercise groups were given 2 h of basketball training for 5 d a week and for 8 weeks. The control group was randomly selected among the adolescents who did not regularly exercise.

RESULTS

The apelin and ghrelin levels significantly increased; however, leptin, irisin, and insulin levels statistically decreased in the post-exercise group compared to the other groups (p < .05). The results suggest low levels of cholesterol, triglyceride, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) parameters (p < .05).

CONCLUSIONS

This study demonstrated that after 8 weeks of chronic exercise training, apelin and ghrelin levels increased; in contrast, leptin, irisin, and insulin levels decreased. The decrease in leptin and irisin levels is compatible with the pattern of decrease in the lipid levels as a result of chronic exercise.

Acute Response to Capsiate Supplementation at Rest and during Exercise on Energy Intake, Appetite, Metabolism, and Autonomic Function: A Randomized Trial

OBJECTIVE

The purpose of the present study was to examine the effect of capsiate supplementation on energy intake, self-reported appetite-related sensations, energy expenditure, fat oxidation, and autonomic parameters with and without an exercise intervention.

METHODS

Thirteen healthy men completed four randomized trials: two trials for the control condition (without exercise), one with capsiate supplementation (CTRL_cap) and one with a placebo (CTRL_pla), and two trials for the exercise condition, one with capsiate supplementation (EX_cap) and one with placebo (EX_pla). Exercise sessions were performed 150 min after the consumption of a standardized breakfast, and supplementation 115 min after consumption of breakfast. An ad libitum buffet was offered 200 min following the completion of the standardized breakfast, and energy intake (EI) and relative energy intake (REI) (relative energy intake = energy intake - energy expenditure related to exercise) were evaluated.

RESULTS

There were no significant effects on EI, self-reported appetite sensations, fat oxidation, and energy expenditure. REI was reduced in conditions involving EX when compared to CTRL. A low-frequency to high-frequency ratio for heart rate variability was higher in CTRL_cap (1.6 ± 1.1) vs. CTRL_pla (1.2 ± 0.9) (p = 0.025; d = 0.39).

CONCLUSION

Acute capsiate supplementation combined with aerobic exercise has limited effects on the examined variables (EI, REI, fat oxidation, energy expenditure, and autonomic parameters), while changes in the autonomic nervous system function in the absence of exercise may have occurred without influencing other variables.

CLINICAL TRIAL REGISTRATION

ensaiosclinicos.gov.br number, RBR-5pckyr https://ensaiosclinicos.gov.br/rg/RBR-5pckyr.

Overtraining Syndrome (OTS) and Relative Energy Deficiency in Sport (RED-S): Shared Pathways, Symptoms and Complexities

The symptom similarities between training-overload (with or without an Overtraining Syndrome (OTS) diagnosis) and Relative Energy Deficiency in Sport (RED-S) are significant, with both initiating from a hypothalamic-pituitary origin, that can be influenced by low carbohydrate (CHO) and energy availability (EA). In this narrative review we wish to showcase that many of the negative outcomes of training-overload (with, or without an OTS diagnosis) may be primarily due to misdiagnosed under-fueling, or RED-S, via low EA and/or low CHO availability. Accordingly, we undertook an analysis of training-overload/OTS type studies that have also collected and analyzed for energy intake (EI), CHO, exercise energy expenditure (EEE) and/or EA. Eighteen of the 21 studies (86%) that met our criteria showed indications of an EA decrease or difference between two cohorts within a given study (n = 14 studies) or CHO availability decrease (n = 4 studies) during the training-overload/OTS period, resulting in both training-overload/OTS and RED-S symptom outcomes compared to control conditions. Furthermore, we demonstrate significantly similar symptom overlaps across much of the OTS (n = 57 studies) and RED-S/Female Athlete Triad (n = 88 studies) literature. It is important to note that the prevention of under-recovery is multi-factorial, but many aspects are based around EA and CHO availability. Herein we have demonstrated that OTS and RED-S have many shared pathways, symptoms, and diagnostic complexities. Substantial attention is required to increase the knowledge and awareness of RED-S, and to enhance the diagnostic accuracy of both OTS and RED-S, to allow clinicians to more accurately exclude LEA/RED-S from OTS diagnoses.

Relationship of Carbohydrate Intake during a Single-Stage One-Day Ultra-Trail Race with Fatigue Outcomes and Gastrointestinal Problems: A Systematic Review

Due to the high metabolic and physical demands in single-stage one-day ultra-trail (SOUT) races, athletes should be properly prepared in both physical and nutritional aspects in order to delay fatigue and avoid associated difficulties. However, high carbohydrate (CHO) intake would seem to increase gastrointestinal (GI) problems. The main purpose of this systematic review was to evaluate CHO intake during SOUT events as well as its relationship with fatigue (in terms of internal exercise load, exercise-induced muscle damage (EIMD) and post-exercise recovery) and GI problems. A structured search was carried out in accordance with PRISMA guidelines in the following: Web of Science, Cochrane Library and Scopus databases up to 16 March 2021. After conducting the search and applying the inclusion/exclusion criteria, eight articles in total were included in this systematic review, in all of which CHO intake involved gels, energy bars and sports drinks. Two studies associated higher CHO consumption (120 g/h) with an improvement in internal exercise load. Likewise, these studies observed that SOUT runners whose intake was 120 g/h could benefit by limiting the EIMD observed by CK (creatine kinase), LDH (lactate dehydrogenase) and GOT (aspartate aminotransferase), and also improve recovery of high intensity running capacity 24 h after a trail marathon. In six studies, athletes had GI symptoms between 65–82%. In summary, most of the runners did not meet CHO intake standard recommendations for SOUT events (90 g/h), while athletes who consumed more CHO experienced a reduction in internal exercise load, limited EIMD and improvement in post-exercise recovery. Conversely, the GI symptoms were recurrent in SOUT athletes depending on altitude, environmental conditions and running speed. Therefore, a high CHO intake during SOUT events is important to delay fatigue and avoid GI complications, and to ensure high intake, it is necessary to implement intestinal training protocols.

Effects of moderate to vigorous intensity cycling on appetite, ad libitum energy intake and appetite-related hormones in healthy South Asian and white European men

Compensatory changes in appetite and energy intake do not appear to occur in the short-term after acute exercise; however, responses have not been compared in South Asians, a group at high risk of central obesity and type 2 diabetes, with white Europeans. This study examined appetite perceptions, energy intake and appetite-related hormones after moderate-to-vigorous intensity cycling in South Asian versus white European men. Fifteen South Asians (mean(SD) 29(8) years; 25.4(4.5) kg m^-2) and fifteen white Europeans (33(10) years; 26.1(3.8) kg m^-2) matched for age and body mass index completed two 7 h trials (control and exercise). Participants rested throughout both trials apart from completing 60 min cycling at 2-3 h in the exercise trial. A standardised breakfast was consumed at 0 h and an ad libitum buffet meal at 4 h. Appetite perceptions and appetite-related hormones were measured at predetermined intervals. Exercise suppressed acylated ghrelin (d = 0.19, P < 0.001) and increased total peptide YY (PYY) (d = 0.14, P = 0.004), insulin (d = 0.09, P = 0.046) and glucose concentrations (d = 0.31, P < 0.001) (main effect of trial), without stimulating compensatory increases in energy intakes in either group (group-by-trial interactions). South Asians exhibited lower absolute energy intake and higher insulin concentrations than white Europeans (main effect group d ≥ 0.63, P ≤ 0.003), whereas group-by-time interactions revealed lower acylated ghrelin concentrations at 3 and 4 h (d ≥ 0.75, P ≤ 0.038) and higher glucose concentrations at 0.75 and 2 h (d ≥ 0.67, P ≤ 0.008) in South Asian than white European men. These findings demonstrate that acute exercise induces a short-term energy deficit and similar appetite responses in South Asian and white European men.

Diet-induced prediabetes: effects of exercise treatment on risk factors for cardiovascular complications

BACKGROUND

An animal model of prediabetes that has been developed in our laboratory using a high fat high carbohydrate diet and lack of physical activity displays risk factors for cardiovascular complications. The effect of exercise against these risk factors in this animal model remains unknown. Therefore, we evaluated the effect of intermittent and regular exercise treatment on the risk factors for cardiovascular complications in this animal model of prediabetes.

METHODS

Following prediabetes induction, animals were randomly assigned to the following groups (n = 6): non-diabetic, prediabetic, intermittently exercising prediabetic and regularly exercising prediabetic. Exercise exposure was 7 weeks long. Body weight changes, caloric intake, blood glucose, total cholesterol, and triglyceride concentration was measured after 20 and 29 weeks while blood pressure was only measured after 29 weeks. Plasma endothelial nitric oxide synthase, malonaldehyde, glutathione peroxidase, tumour necrosis factor-alpha and C-reactive protein concentration from the heart were measured 2 weeks post-exercise termination (week 30).

RESULTS

We found increased body weight, caloric intake and mean arterial pressure in the prediabetic group by comparison to the non-prediabetic group. The same trend was observed in blood glucose and triglyceride concentrations. However, all of these parameters were reduced in the intermittently exercising prediabetic and regularly exercising prediabetic groups. This reduction was further accompanied by a decrease in the endothelial nitric oxide synthase, tumour necrosis factor-alpha and C-reactive protein concentration with improved oxidative stress biomarkers.

CONCLUSIONS

The progression of pre-diabetes to diabetes is slowed or possibly stopped by exercise (regular or intermittent). Additionally, biomarker profiles indicative of cardiovascular disease in pre-diabetics are improved by exercise.

Nutrition for Older Athletes: Focus on Sex-Differences

Regular physical exercise and a healthy diet are major determinants of a healthy lifespan. Although aging is associated with declining endurance performance and muscle function, these components can favorably be modified by regular physical activity and especially by exercise training at all ages in both sexes. In addition, age-related changes in body composition and metabolism, which affect even highly trained masters athletes, can in part be compensated for by higher exercise metabolic efficiency in active individuals. Accordingly, masters athletes are often considered as a role model for healthy aging and their physical capacities are an impressive example of what is possible in aging individuals. In the present review, we first discuss physiological changes, performance and trainability of older athletes with a focus on sex differences. Second, we describe the most important hormonal alterations occurring during aging pertaining regulation of appetite, glucose homeostasis and energy expenditure and the modulatory role of exercise training. The third part highlights nutritional aspects that may support health and physical performance for older athletes. Key nutrition-related concerns include the need for adequate energy and protein intake for preventing low bone and muscle mass and a higher demand for specific nutrients (e.g., vitamin D and probiotics) that may reduce the infection burden in masters athletes. Fourth, we present important research findings on the association between exercise, nutrition and the microbiota, which represents a rapidly developing field in sports nutrition.

Comparing the Effects of Immersed Versus Land-Based High-Intensity Interval Cycling on Energy Intake, Appetite Sensations and Perceived Exertion Among Healthy Men

Immersed exercise has been shown to induce higher energy expenditure and no difference or increase in food intake compared with similar exercise on land. In this study, we compared the effects of acute high-intensity cycling performed on land versus when immersed on subsequent energy intake (EI), appetite sensations and perceived exertion (RPE) in healthy men. Ten participants in a postprandial condition completed three experimental visits in a randomized order: a control condition (CONT); a high-intensity interval cycling exercise performed on land (HIIE-L) and the same exercise while immersed in water (HIIE-A) with a similar targeted heart rate. We observed no difference in energy and macronutrient intake and in area under the curve (AUC) for appetite sensations between sessions. The RPE at the end of HIIE-L was negatively correlated with EI (r=-0.67; p < 0.05), AUC for hunger (r=-0.86, p < 0.01), desire to eat (r=-0.78, p < 0.05) and prospective food consumption (r=-0.86, p < 0.01). Conversely, the RPE at the end of HIIE-L was positively correlated with AUC for fullness (r = 0.76, p < 0.05). No such correlations were observed for HIIE-A. The present study was the first to observe that immersion did not influence EI after HIIE cycling, but immersion blunted the relationship between session RPE and subsequent energy intake and appetite sensations relative to HIIE on land.

Precision nutrition: A systematic literature review

Precision Nutrition research aims to use personal information about individuals or groups of individuals to deliver nutritional advice that, theoretically, would be more suitable than generic advice. Machine learning, a subbranch of Artificial Intelligence, has promise to aid in the development of predictive models that are suitable for Precision Nutrition. As such, recent research has applied machine learning algorithms, tools, and techniques in precision nutrition for different purposes. However, a systematic overview of the state-of-the-art on the use of machine learning in Precision Nutrition is lacking. Therefore, we carried out a Systematic Literature Review (SLR) to provide an overview of where and how machine learning has been used in Precision Nutrition from various aspects, what such machine learning models use as input features, what the availability status of the data used in the literature is, and how the models are evaluated. Nine research questions were defined in this study. We retrieved 4930 papers from electronic databases and 60 primary studies were selected to respond to the research questions. All of the selected primary studies were also briefly discussed in this article. Our results show that fifteen problems spread across seven domains of nutrition and health are present. Four machine learning tasks are seen in the form of regression, classification, recommendation and clustering, with most of these utilizing a supervised approach. In total, 30 algorithms were used, with 19 appearing more than once. Models were through the use of four groups of approaches and 23 evaluation metrics. Personalized approaches are promising to reduce the burden of these current problems in nutrition research, and the current review shows Machine Learning can be incorporated into Precision Nutrition research with high performance. Precision Nutrition researchers should consider incorporating Machine Learning into their methods to facilitate the integration of many complex features, allowing for the development of high-performance Precision Nutrition approaches.

Effects of exercise and diet intervention on appetite-regulating hormones associated with miRNAs in obese children

AIMS

This study investigated the effects of exercise and diet intervention on appetite-regulating hormones and subjective appetite changes in obese children and examined expressions of specific key microRNAs (miRNA, miR).

METHODS

16 obese children were included in a training program consisting of exercise and diet intervention for 6 weeks. Before and after the intervention, fasting blood was collected to determine appetite-regulating hormones (leptin, ghrelin, and orexin) and miRNA (miR-103a-3p and miR-200a-3p) levels; eating behavior of the children was reported using the Children Eating Behavior Questionnaire (CEBQ).

RESULTS

The level of orexin was significantly decreased (P < 0.05), while ghrelin was significantly enhanced (P < 0.05) after 6 weeks. The scores of food responsiveness (FR) and enjoyment of food (EF) of the CEBQ were significantly decreased (P < 0.05) after intervention. The changes of leptin and that of SR were significantly correlated (r = - 0.455, P < 0.05), and the correlation between the alterations of orexin and that of EF was moderate with significance (r = 0.625, P < 0.05). miR-103a-3p expression was not statistically changed, while miR-200a-3p was significantly inhibited after 6-week intervention (P < 0.05). The correlation between relative changes of miR-103a-3p and that of leptin and orexin were both with significant difference (r = 0.413, P < 0.05; r = 0.409, P < 0.05), whereas the alterations of miR-200a-3p were not correlative with hormones or appetite sensation.

CONCLUSION

Exercise combined with diet intervention for 6 weeks was effective in regulating appetite sensations and hormones in obese children, and miR-103a-3p and miR-200a-3p might provide a foundation for target biomarkers of appetite trait in modulating the energy balance control by exercise and dietary intervention.

LEVEL OF EVIDENCE

Level III, case-control analytic study.

TRIAL REGISTRATION

The trial was registered in ClinicalTrials.gov (NCT03762629).

Planned morning aerobic exercise in a fasted state increases energy intake in the preceding 24 h

Purpose

We previously observed increased energy intake (EI) at the meal before planned afternoon exercise, but the proximity of the meal to exercise might have reduced the scale of the pre-exercise anticipatory eating. Therefore, this study examined EI in the 24 h before fasted morning exercise.

Methods

Fourteen males, experienced with gym-based aerobic exercise (age 25 ± 5 years, BMI 23.8 ± 2.5 kg/m²), completed counterbalanced exercise (EX) and resting (REST) trials. On day 1, subjects were told the following morning’s activity (EX/REST), before eating ad-libitum laboratory-based breakfast and lunch meals and a home-based afternoon/evening food pack. The following morning, subjects completed 30-min cycling and 30-min running (EX; 3274 ± 278 kJ) or 60-min supine rest (REST; 311 ± 34 kJ) fasted. Appetite was measured periodically, and EI quantified.

Results

Afternoon/evening EI (EX 7371 ± 2176 kJ; REST 6437 ± 2070 kJ; P = 0.017) and total 24-h EI (EX 14,055 ± 3672 kJ; REST 12,718 ± 3379 kJ; P = 0.011) were greater during EX, with no difference between trials at breakfast (P = 0.761) or lunch (P = 0.071). Relative EI (EI minus energy expended through EX/REST) was lower in EX (EX 10,781 ± 3539 kJ; REST 12,407 ± 3385 kJ; P = 0.004).

Conclusion

This study suggests planned fasted aerobic exercise increases EI during the preceding afternoon/evening, precipitating a ~ 10% increase in EI in the preceding 24-h. However, this increase did not fully compensate for energy expended during exercise; meaning exercise induced an acute negative energy balance.

Energy Balance Dynamics: Exercise, Appetite, Diet, and Weight Control

Individuals seeking to achieve weight loss are encouraged to achieve a negative energy balance, essentially eat less and move more. The complex relationship between energy expenditure and intake is often overlooked, leaving individuals and practitioners underwhelmed by the results of weight loss efforts. Independently, physical activity and diet interventions can yield modest weight loss and when combined have synergistic effects that promote sustained weight loss. Although physical activity benefits appetite suppression, reduces food rewards, and can be considered a gateway to healthy eating, high levels of daily activity are needed to induce weight loss. Diet is an important component to achieving weight loss, and high-protein diets have the potential for supporting weight loss as well. This column will be focused on the benefits of physical activity in reducing body weight, more specifically, the interdependent relationship between dietary intake and physical activity in achieving weight reduction.

Changes in iron metabolism centered on hepcidin due to high-intensity exercise under restricted food intake

OBJECTIVES

The purpose of this study was to observe changes in iron metabolism of rats due to high-intensity exercise during reduced food intake.

METHODS

Thirty-six, 4-wk-old male Wistar rats were divided into six groups after being acclimated to running: rested control, intense exercise, 80% feeding and rested, 80% feeding and intense exercise, 70% feeding diet and rested, and 70% feeding and intense exercise groups. Only three intense exercise groups underwent acute running sessions for 30 min (30 m/min) once a day for 7 d.

RESULTS

Rats did not develop anemia with exercise and food intake restriction. Serum iron levels, transferrin saturation, hepcidin-25, and hepatic iron levels in the exercise groups were lower than those in the respective resting groups. However, these values in the 70% diet groups were slightly higher than those in the 80% diet groups. Serum erythropoietin levels decreased as food intake decreased, but the serum erythropoietin level in the 70% feeding and intense exercise group was similar to that in the rested control group. Serum interleukin-6 levels were significantly lower in the groups with restricted food intake than in the free-fed group, and exercise had no effect.

CONCLUSIONS

High-intensity exercise under restricted food intake may significantly alter the iron metabolism to maintain blood cell levels due to the strong promotion of metabolic iron utilization in response to dietary iron depletion, increased iron demand, and excretion.

Effect of an office-based intervention on visceral adipose tissue: the WorkACTIVE-P randomized controlled trial

Office-based activity reduces sedentariness, yet no randomized controlled trials (RCTs) have assessed how such activity influences visceral adipose tissue (VAT). This study examined the effect of an office-based, multicomponent activity intervention on VAT. The WorkACTIVE-P RCT enrolled sedentary office workers (body mass index: 31.4 (standard deviation (SD) 4.4) kg/m²) to an intervention (n = 20) or control (n = 20) group. For 3 months, the intervention group received an office-based pedal desk, further to an intervention promoting its use and increased walking. The control group maintained habitual activity. At baseline and follow-up, VAT, cardiometabolic disease risk markers, physical activity, and food intake were measured. Steps/day were not altered relative to control (P ≥ 0.51), but the pedal desk was utilized for 127 (SD 61) min/day. The intervention reduced VAT relative to control (-0.15 kg; 95% confidence interval (CI) = -0.29 to -0.01; P = 0.04). Moreover, the intervention decreased fasting glucose compared with control (-0.29 mmol/L; 95% CI = -0.51 to -0.06; P = 0.01), but no differences in other cardiometabolic disease markers or food intake were revealed (P ≥ 0.11). A multicomponent intervention decreased VAT in office workers who were overweight or obese. Though longer-term studies are needed, office-based, multicomponent activity regimens may lower cardiometabolic disease risk. Trial registered at ClinicalTrials.gov (NCT02561611). Novelty: In WorkACTIVE-P, a multicomponent activity intervention decreased visceral adipose tissue relative to control in office workers. The intervention also reduced glucose compared with control, though other metabolic risk markers and food intake were not altered. Such multicomponent interventions could help reduce cardiometabolic disease risk, but longer studies are needed.

Consumption of a High-Protein Meal Replacement Leads to Higher Fat Oxidation, Suppression of Hunger, and Improved Metabolic Profile After an Exercise Session

The aim of this study was to compare the impact of a high-protein meal replacement (HP-MR) versus a control (CON) breakfast on exercise metabolism. In this acute, randomized controlled, cross-over study, participants were allocated into two isocaloric arms: (a) HP-MR: 30% carbohydrate, 43% protein, and 27% fat; (b) CON: 55% carbohydrate, 15% protein, and 30% fat. Following breakfast, participants performed a moderate-intensity aerobic exercise while inside a whole-body calorimetry unit. Energy expenditure, macronutrient oxidation, appetite sensations, and metabolic blood markers were assessed. Forty-three healthy, normal-weight adults (24 males) participated. Compared to the CON breakfast, the HP-MR produced higher fat oxidation (1.07 ± 0.33 g/session; p = 0.003) and lower carbohydrate oxidation (-2.32 ± 0.98 g/session; p = 0.023) and respiratory exchange ratio (-0.01 ± 0.00; p = 0.003) during exercise. After exercise, increases in hunger were lower during the HP-MR condition. Changes in blood markers from the fasting state to post-exercise during the HP-MR condition were greater for insulin, peptide tyrosine-tyrosine, and glucagon-like peptide 1, and lower for low-density lipoprotein cholesterol, triglyceride, and glycerol. Our primary findings were that an HP-MR produced higher fat oxidation during the exercise session, suppression of hunger, and improved metabolic profile after it.

Energy Status Differentially Modifies Feeding Behavior and POMCARC Neuron Activity After Acute Treadmill Exercise in Untrained Mice

Emerging evidence identifies a potent role for aerobic exercise to modulate activity of neurons involved in regulating appetite; however, these studies produce conflicting results. These discrepancies may be, in part, due to methodological differences, including differences in exercise intensity and pre-exercise energy status. Consequently, the current study utilized a translational, well-controlled, within-subject, treadmill exercise protocol to investigate the differential effects of energy status and exercise intensity on post-exercise feeding behavior and appetite-controlling neurons in the hypothalamus. Mature, untrained male mice were exposed to acute sedentary, low (10m/min), moderate (14m/min), and high (18m/min) intensity treadmill exercise in a randomized crossover design. Fed and 10-hour-fasted mice were used, and food intake was monitored 48h. post-exercise. Immunohistochemical detection of cFOS was performed 1-hour post-exercise to determine changes in hypothalamic NPY/AgRP, POMC, tyrosine hydroxylase, and SIM1-expressing neuron activity concurrent with changes in food intake. Additionally, stains for pSTAT3^tyr705 and pERK^{thr202/tyr204} were performed to detect exercise-mediated changes in intracellular signaling. Results demonstrated that fasted high intensity exercise suppressed food intake compared to sedentary trials, which was concurrent with increased anorexigenic POMC neuron activity. Conversely, fed mice experienced augmented post-exercise food intake, with no effects on POMC neuron activity. Regardless of pre-exercise energy status, tyrosine hydroxylase and SIM1 neuron activity in the paraventricular nucleus was elevated, as well as NPY/AgRP neuron activity in the arcuate nucleus. Notably, these neuronal changes were independent from changes in pSTAT3^tyr705 and pERK^{thr202/tyr204} signaling. Overall, these results suggest fasted high intensity exercise may be beneficial for suppressing food intake, possibly due to hypothalamic POMC neuron excitation. Furthermore, this study identifies a novel role for pre-exercise energy status to differentially modify post-exercise feeding behavior and hypothalamic neuron activity, which may explain the inconsistent results from studies investigating exercise as a weight loss intervention.

An Increase in Fat-Free Mass is Associated with Higher Appetite and Energy Intake in Older Adults: A Randomised Control Trial

Cross-sectional studies in younger adults have demonstrated a positive association between energy intake (EI) and fat-free mass (FFM), with this relationship seemingly mediated by resting metabolic rate (RMR). Establishing a causal effect longitudinally would be prudent in older adults suffering from loss of appetite. We investigated the effects of FFM on RMR, appetite and EI in 39 healthy older adults (age: 66 ± 4 years, BMI: 25.1 ± 3.5 kg∙m²) assigned to either 12-week resistance training + protein supplementation group (RT + PRO) or control group (CON). Body composition, subjective appetite, leptin, insulin, RMR and laboratory-measured ad libitum EI were measured at baseline, weeks 6 and 12 of the intervention, while daily EI at baseline and week 12. FFM (+1.2 kg; p = 0.002), postprandial subjective appetite (+8 mm; p = 0.027), ad libitum EI (+119 kcal; p = 0.012) and daily EI (+133 kcal; p = 0.010) increased from baseline to week 12 in the RT + PRO. RMR, fasted subjective appetite, leptin and insulin concentrations remained unchanged (all p > 0.05). The increases ad libitum EI correlated with increases in FFM (r = 0.527, p = 0.001), with 54% of the change in EI attributed to FFM changes. In conclusion, FFM increases were associated with an increased ad libitum EI and postprandial appetite in older adults.

Latent Class Analysis of Lifestyle Risk Factors and Association with Overweight and/or Obesity in Children and Adolescents: Systematic Review

Background: Multiple modifiable lifestyle factors are well-known contributors to many health problems. Objectives: This study aims to determine the association between latent class analysis (LCA) of modifiable lifestyle risk factors with being overweight and/or obese for children and/or adolescents. Methods: Articles were selected from six databases, without limitation regarding language or date. The review included studies that identify latent classes of modifiable lifestyle risk factors [e.g., physical activity (PA), diet, sedentary behavior (SB), and/or unhealthy behavior] by LCA to determine the association between latent classes with being overweight and/or obese. The methodology of the selected studies was evaluated using the JBI Critical Appraisal Checklist for Analytical Cross-Sectional Studies. Owing to the heterogeneity between latent classes of modifiable lifestyle risk factors with obesity and/or being overweight, the results are described narratively. Results: Using a selection process in two phases, nine articles were included. All of the included studies were of high methodological quality. The studies were conducted in six different countries: the USA, Brazil, Canada, Portugal, Italy, and Australia. Sample sizes ranged from 166 to 18.587 children and adolescents, and in terms of age (range 5-19 years). Across study clusters characterized by low consumption of fruit and vegetables, and high consumption of fatty foods, sugar snack foods, sweets, chips and fries, low PA (<1 hour each day), and high SB (screen time and TV >2 hours/day), sleep time (<10 hours/day) were positively associated with being overweight and/or obese. Conclusion: Overall there is good evidence to support that the modifiable lifestyle risk factors clustered together by LCA should be novel targets for the treatment of obesity and its associated comorbidities.

Physical Activity as an Imperative Support in Breast Cancer Management

Breast cancer (BC) is the most common malignancy and the second cause of cancer-related death among women. It is estimated that 9 in 10 cases of BC are due to non-genetic factors, and approximately 25% to 30% of total breast cancer cases should be preventable only by lifestyle interventions. In this context, physical activity represents an excellent and accessible approach not only for the prevention, but also for being a potential support in the management of breast cancer. The present review will collect the current knowledge of physical activity in the background of breast cancer, exploring its systemic and molecular effects, considering important variables in the training of these women and the evidence regarding the benefits of exercise on breast cancer survival and prognosis. We will also summarize the various effects of physical activity as a co-adjuvant therapy in women receiving different treatments to deal with its adverse effects. Finally, we will reveal the impact of physical activity in the enhancement of quality of life of these patients, to conclude the central role that exercise must occupy in breast cancer management, in an adequate context of a healthy lifestyle.

The effects of moderate alterations in adrenergic activity on acute appetite regulation in obese women: A randomised crossover trial

BACKGROUND

Previous evidence has demonstrated that serum leptin is correlated with appetite in combination with, but not without, modest exercise.

AIM

The present experiments investigated the effects of exogenous adrenaline and α/β adrenoceptor blockade in combination with moderate exercise on serum leptin concentrations, appetite/satiety sensations and subsequent food intake in obese women.

METHODS

A total of 10 obese women ((mean ± SEM), age: 50 (1.9) years, body mass index 36 (4.1) kg/m2, waist 104.8 (4.1) cm) participated in two separate, double-blind randomised experimental trials. Experiment 1: moderate exercise after α/β adrenergic blocker (labetalol, 100 mg orally) versus moderate exercise plus placebo; experiment 2: adrenaline infusion for 20 minutes versus saline infusion. Appetite/satiety and biochemistry were measured at baseline, pre- and immediately post-intervention, then 1 hour post-intervention (i.e., before dinner). Food intake was assessed via ad libitum buffet-style dinner.

RESULTS

No differences were found in appetite/satiety, subsequent food intake or serum leptin in any of the studies (experiment 1 or experiment 2). In experiment 1, blood glucose was higher (p < 0.01) and plasma free fatty acids lower (p = 0.04) versus placebo. In experiment 2, plasma free fatty acids (p < 0.05) increased after adrenaline versus saline infusion.

CONCLUSIONS

Neither inhibition of exercise-induced adrenergic activity by combined α/β adrenergic blockade nor moderate increases in adrenergic activity induced by intravenous adrenaline infusion affected acute appetite regulation.

A Time to Eat and a Time to Exercise

Analogous to exercise training, time-restricted eating may rescue some of the deleterious effects on metabolic health induced by our modern-day lifestyle.

This Perspective for Progress provides a synopsis for the potential of time-restricted eating (TRE) to rescue some of the deleterious effects on circadian biology induced by our modern-day lifestyle. We provide novel insights into the comparative and potential complementary effects of TRE and exercise training on metabolic health.

Effect of Physical Exercise on Taste Perceptions: A Systematic Review

The effect of physical exercise on nutrition has gained substantial interest in the last decade. Meaningful results have been produced concerning the effect of physical exercise on different appetite hormones and food choice/preference. While it is well known that taste and nutrition are related, the relation between taste and physical activity has not yet been fully explored. This systematic review aims to provide a detailed view of the literature on physical exercise and its effect on taste perceptions. Five tastes were included in this review: sweet, salty, bitter, sour, and umami. Sweet taste intensity, sensitivity, and preference were increased by acute physical exercise, but sweet preference was reduced by chronic physical activity. Perceived intensity and sensitivity decreased overall for salty taste, but an increased preference was noted during/following exercise. Sour taste intensity ratings were decreased following exercise and preference was enhanced. Umami taste intensity and sensitivity increased following exercise and preference was decreased. No significant results were obtained for bitter taste. While evidence regarding the effect of exercise on taste has arisen from this review, the pre-testing nutrition, testing conditions, type of test, and exercise modality must be standardized in order to produce meaningful and reproducible results in the future.

(Neuro) Peptides, Physical Activity, and Cognition

Regular physical activity (PA) improves cognitive functions, prevents brain atrophy, and delays the onset of cognitive decline, dementia, and Alzheimer’s disease. Presently, there are no specific recommendations for PA producing positive effects on brain health and little is known on its mediators. PA affects production and release of several peptides secreted from peripheral and central tissues, targeting receptors located in the central nervous system (CNS). This review will provide a summary of the current knowledge on the association between PA and cognition with a focus on the role of (neuro)peptides. For the review we define peptides as molecules with less than 100 amino acids and exclude myokines. Tachykinins, somatostatin, and opioid peptides were excluded from this review since they were not affected by PA. There is evidence suggesting that PA increases peripheral insulin growth factor 1 (IGF-1) levels and elevated serum IGF-1 levels are associated with improved cognitive performance. It is therefore likely that IGF-1 plays a role in PA induced improvement of cognition. Other neuropeptides such as neuropeptide Y (NPY), ghrelin, galanin, and vasoactive intestinal peptide (VIP) could mediate the beneficial effects of PA on cognition, but the current literature regarding these (neuro)peptides is limited.

GDF15: A Hormone Conveying Somatic Distress to the Brain

GDF15 has recently gained scientific and translational prominence with the discovery that its receptor is a GFRAL-RET heterodimer of which GFRAL is expressed solely in the hindbrain. Activation of this receptor results in reduced food intake and loss of body weight and is perceived and recalled by animals as aversive. This information encourages a revised interpretation of the large body of previous research on the protein. GDF15 can be secreted by a wide variety of cell types in response to a broad range of stressors. We propose that central sensing of GDF15 via GFRAL-RET activation results in behaviors that facilitate the reduction of exposure to a noxious stimulus. The human trophoblast appears to have hijacked this signal, producing large amounts of GDF15 from early pregnancy. We speculate that this encourages avoidance of potential teratogens in pregnancy. Circulating GDF15 levels are elevated in a range of human disease states, including various forms of cachexia, and GDF15-GFRAL antagonism is emerging as a therapeutic strategy for anorexia/cachexia syndromes. Metformin elevates circulating GDF15 chronically in humans and the weight loss caused by this drug appears to be dependent on the rise in GDF15. This supports the concept that chronic activation of the GDF15-GFRAL axis has efficacy as an antiobesity agent. In this review, we examine the science of GDF15 since its identification in 1997 with our interpretation of this body of work now being assisted by a clear understanding of its highly selective central site of action.

The Role of Exercise in the Interplay between Myokines, Hepatokines, Osteokines, Adipokines, and Modulation of Inflammation for Energy Substrate Redistribution and Fat Mass Loss: A Review

Exercise is an effective strategy for preventing and treating obesity and its related cardiometabolic disorders, resulting in significant loss of body fat mass, white adipose tissue browning, redistribution of energy substrates, optimization of global energy expenditure, enhancement of hypothalamic circuits that control appetite-satiety and energy expenditure, and decreased systemic inflammation and insulin resistance. Novel exercise-inducible soluble factors, including myokines, hepatokines, and osteokines, and immune cytokines and adipokines are hypothesized to play an important role in the body's response to exercise. To our knowledge, no review has provided a comprehensive integrative overview of these novel molecular players and the mechanisms involved in the redistribution of metabolic fuel during and after exercise, the loss of weight and fat mass, and reduced inflammation. In this review, we explain the potential role of these exercise-inducible factors, namely myokines, such as irisin, IL-6, IL-15, METRNL, BAIBA, and myostatin, and hepatokines, in particular selenoprotein P, fetuin A, FGF21, ANGPTL4, and follistatin. We also describe the function of osteokines, specifically osteocalcin, and of adipokines such as leptin, adiponectin, and resistin. We also emphasize an integrative overview of the pleiotropic mechanisms, the metabolic pathways, and the inter-organ crosstalk involved in energy expenditure, fat mass loss, reduced inflammation, and healthy weight induced by exercise.

Exercise-related factors that influence post-exercise energy intake: A psychological perspective

OBJECTIVES

Exercise confers numerous health benefits; however, unhealthy, or excessive food and drink consumption post-exercise may counteract at least some of these benefits. There is emerging evidence that certain exercise-related factors, including the psychological experiences associated with different forms of exercise motivation, may influence post-exercise energy intake. Questions remain, though, about the optimal exercise characteristics that may reduce overconsumption of food/drink post-exercise.

DESIGN

Narrative review.

METHODS

In this narrative review, we overview the developing body of literature linking the psychological experiences in exercise with subsequent energy intake, focusing first on the relationship between exercise motivation and food consumption, and then on practical strategies which may be utilised to promote healthier post-exercise food choices.

RESULTS

Preliminary evidence suggests that psychological experiences associated with high-quality autonomous motivation for exercise may reduce subsequent energy intake. Exercise factors (both psychological and physiological in nature) that have been shown to influence post-exercise energy consumption may interact, resulting in synergistic or antagonistic effects on subsequent food and drink consumption, through mechanisms which have not been considered previously.

CONCLUSIONS

Exercise experiences may be shaped to promote healthier subsequent eating behaviours and future work is encouraged to enable researchers to identify combinations of exercise conditions and experiences that have the strongest influence on post-exercise food and drink consumption.

Metabolic Impacts of Confinement during the COVID-19 Pandemic Due to Modified Diet and Physical Activity Habits

While the detrimental effects of a chronic positive energy balance due to a sedentary lifestyle have been well established, the impacts of a short period of abruptly reduced physical activity and overeating arising from strict confinement due to the COVID-19 pandemic will soon start to emerge. To reasonably anticipate major consequences according to the available evidence, we hereby review the literature for studies that have explored the health impacts of several weeks of a reduction in physical activity and daily step-count combined with modified eating habits. These studies identify as main metabolic consequences increases in insulin resistance, total body fat, abdominal fat and inflammatory cytokines. All these factors have been strongly associated with the development of metabolic syndrome, which in turn increases the risk of multiple chronic diseases. A plausible mechanism involved in these impacts could be a positive energy balance promoted by maintaining usual dietary intake while reducing energy expenditure. This means that just as calorie intake restriction could help mitigate the deleterious impacts of a bout of physical inactivity, overeating under conditions of home confinement is very likely to exacerbate these consequences. Moreover, hypertension, diabetes, and cardiovascular disease have been identified as potential risk factors for more severely ill patients with COVID-19. Thus, adequate control of metabolic disorders could be important to reduce the risk of severe COVID-19.

Baseline Habitual Physical Activity Predicts Weight Loss, Weight Compensation, and Energy Intake During Aerobic Exercise

OBJECTIVE

This study aimed to determine whether different measures of habitual physical activity (PA) at baseline predict weight change, weight compensation, and changes in energy intake (EI) during a 24-week supervised aerobic exercise intervention.

METHODS

Data from 108 participants (78 women; 48.7 [SD: 11.6] years; BMI 31.4 [SD: 4.6] kg/m² ), randomly assigned to either the moderate-dose exercise group (8 kcal/kg of body weight per week) or the high-dose exercise group (20 kcal/kg of body weight per week) of the Examination of Mechanisms of Exercise-induced Weight Compensation (E-MECHANIC) trial, were analyzed. Moderate-to-vigorous PA (MVPA), steps per day, and PA energy expenditure (PAEE) were measured with SenseWear armbands (BodyMedia, Pittsburgh, Pennsylvania), and total activity energy expenditure and EI were estimated with doubly labeled water, all over 2 weeks, before and toward the end of the intervention. Multiple linear regression models, adjusted for sex, exercise group, and baseline value of the outcome, were used.

RESULTS

Baseline habitual MVPA levels predicted weight change (β = -0.275; P = 0.020), weight compensation (β = -0.238; P = 0.043), and change in EI (β = -0.318; P = 0.001). Associations between baseline PAEE and outcomes were comparable, whereas steps per day and, importantly, total activity energy expenditure (via doubly labeled water) did not significantly predict change in weight-related outcomes.

CONCLUSIONS

While acknowledging substantial variability in the data, on average, lower baseline habitual MVPA and PAEE levels were associated with less weight loss from exercise, higher compensation, and increased EI.

High-intensity Interval Training Promotes the Shift to a Health-Supporting Dietary Pattern in Young Adults

A healthy lifestyle is based on a correct diet and regular exercise. Little is known about the effect of different types of exercise on dietary preferences. To address the question of whether high-intensity interval training (HIIT) could modulate spontaneous food choices, an experimental study was carried out on 32 young, healthy normal-weight subjects. The spontaneous diet of each subject has been monitored over nine weeks of indoor-cycling training, divided into three mesocycles with an incremental pattern: total energy intake, macronutrients and micronutrients have been analysed. A two-way mixed model has been used to assess differences in dietary variables; a principal factor analysis has been performed to identify sample subgroups. An increased energy intake (+17.8% at T3; p < 0.01) has been observed, although macronutrients' proportions did not vary over time, without differences between sexes. An increase of free fat mass was found in the last mesocycle (+3.8%), without an augmentation of body weight, when, despite the increased training load, a stabilization of energy intake occurred. Three different subgroups characterized by different dietary modifications could be identified among participants that showed a common trend towards a healthier diet. Nine weeks of HIIT promoted a spontaneous modulation of food choices and regulation of dietary intake in young normal-weight subjects aged 21-24. Importantly, this life-period is critical to lay the foundation of correct lifestyles to prevent metabolic diseases and secure a healthy future with advancing age.

Interactions of sprint interval exercise and psychological need-support on subsequent food intake among physically inactive men and women

The aim of this study was to investigate the effect of sprint interval training (SIT) and psychological need-support in exercise on postexercise appetite and energy intake. Forty physically inactive men and women (body mass index, 24.6 ± 4.8 kg·m^-2; peak oxygen consumption, 26.6 ± 4.9 mL·kg^-1·min^-1) were randomised to either a need-support or no-support condition, with each participant completing 2 experimental trials involving 30 min of moderate-intensity continuous training (MICT; 60% peak oxygen consumption) and SIT (alternating 15 s at 170% peak oxygen consumption and 60 s at 32% peak oxygen consumption) matched for total work. Perceptions of appetite and appetite-related blood variables were assessed, together with ad libitum energy intake for 3 h following exercise using a laboratory test meal and available snacks. Greater enjoyment, perceived exertion, heart rate, and blood lactate were observed in SIT compared with MICT (all p ≤ 0.006). Ratings of perceived appetite were similar across conditions and trials (p > 0.05); however, active ghrelin was lower following SIT compared with MICT (p < 0.001), and there was a significant condition-by-type interaction for energy intake (p = 0.033), with participants in the support group consuming less energy from foods following SIT (1895 ± 1040 kJ) than MICT (2475 ± 1192 kJ). Findings from this work highlight the need to reconsider traditional exercise guidelines where dietary intake is a concern. Novelty Enjoyment was greater during SIT compared with MICT. Enjoyment and choice were higher among participants provided with psychological need-support. In a need-supportive environment, SIT reduced subsequent energy intake compared with MICT.

Impact of Exercise Timing on Chemosensory Response, Appetite, and Energy Intake in Lean Males

BACKGROUND

High-intensity exercise can have an anorectic impact, leading to negative energy balance. Several studies have reported that the practice of physical activity could also cause a shift in perceptions and preferences, causing a change in food intakes.

OBJECTIVE

This study aimed to question to what extent the timing of exercise in relation to a meal could have an impact on olfaction and gustation, appetite, and food choices.

METHODS

Twelve males aged 25 (4) years with a body mass index of 22.4 (2.0) kg/m2 attended two experimental visits in a counterbalanced fashion. The participants consumed a standardized breakfast between 7:00 and 7:30 a.m. and were subjected to smell and taste tests upon arrival at the laboratory (8:30 a.m.). In the EX9:40 visit, the participants performed a 30-min exercise session (70% of maximum oxygen uptake) at 9:40 a.m., followed by a 90-min sedentary break. In EX10:30, the participants first took part in the 90-min sedentary break and then performed the 30-min exercise session at 10:30 a.m. Taste and smell tests were performed again at 11:40 a.m., immediately followed by an ad libitum buffet-style meal. Visual analog scales were used to report appetite sensations during the session and satiety quotients around the lunch.

RESULTS

There was no difference in energy intakes between the EX9:40 (596 [302] kcal) and EX10:30 (682 [263] kcal) conditions (p = .459). There was no condition effect for the taste and smell sensations (all ps > .05), appetite sensation, or satiety quotients around the meal (all ps > .05).

CONCLUSION

Exercise timing in the morning had no effect on taste and smell perceptions, appetite sensations, or energy intakes.