Impact of the menstrual cycle on determinants of energy balance: a putative role in weight loss attempts

Sex- and Gender-Related Differences in Obesity: From Pathophysiological Mechanisms to Clinical Implications

Obesity, primarily characterized by excessive fat accumulation, is a multifactorial chronic disease with an increasing global prevalence. Despite the well-documented epidemiology and significant advances in understanding its pathophysiology and clinical implications, the impact of sex is typically overlooked in obesity research. Worldwide, women have a higher likelihood to become obese compared to men. Although women are offered weight loss interventions more often and at earlier stages than men, they are more vulnerable to psychopathology. Men, on the other hand, are less likely to pursue weight loss intervention and are more susceptible to the metabolic implications of obesity. In this narrative review, we comprehensively explored sex- and gender-specific differences in the development of obesity, focusing on a variety of biological variables, such as body composition, fat distribution and energy partitioning, the impact of sex steroid hormones and gut microbiota diversity, chromosomal and genetic variables, and behavioural and sociocultural variables influencing obesity development in men and women. Sex differences in obesity-related comorbidities and varying effectiveness of different weight loss interventions are also extensively discussed.

The awareness of renal stones amongst Syrian refugees in northern Jordan

Kidney Stone Disease (KSD) is a globally prevalent condition that can be effectively addressed through proper education. This study investigated the awareness of kidney stones among refugees residing in northern Jordan. A questionnaire was administered to 487 refugees of diverse ages and socioeconomic backgrounds. Notably, 97.3% of the respondents had not attended university, and 30.8% held unskilled jobs. Upon familiarizing themselves with the signs and symptoms of kidney stones, 16.22% of men and 12.32% of women reported experiencing such symptoms. This revealed a significant association, suggesting that men might be more susceptible to developing kidney stones than women due to a lack of medical follow-up and examination for men in the camp. However, 38.77% of individuals were uncertain whether they had kidney stones. Furthermore, 38.96% of refugees were unsure about which healthcare professional to consult when experiencing kidney stone symptoms. This report highlights a serious issue with refugees' knowledge of the symptoms, causes, and treatments for kidney stones. The results indicate that Syrian refugees face challenges in acquiring adequate disease awareness, potentially related to issues of migration and war, including low levels of education, limited income, living in camps, and difficulties accessing treatments when needed. Implementing additional policies is necessary to address these challenges among Syrian refugees; however, further studies are needed to validate these findings.

Optimization of the seat position for a personal vehicle equipped with a crankset: pilot study

The aim of the study was to optimize the seat for a personal vehicle equipped with a crankset mechanism, meant for everyday use. The inclination of the seat backrest was selected on the basis of theoretical considerations. Then dynamic tests were carried out on a group of young, healthy men in order to verify the ergonomic aspects of the seat position in relation to the crankset and determine the efficiency of the human-mechanism system with a load of 50 W. The data obtained from the dynamic tests were subject to statistical analysis. Research has shown that higher seat positions result in statistically higher efficiencies. In addition, a holistic analysis of the personal vehicle design problem shows that the upper position of the seat is also the best. The results of the research can be used to optimize personal vehicles using human force as a drive.

Resting energy metabolism and sweet taste preference during the menstrual cycle in healthy women

Differences in blood concentration of sex hormones in the follicular (FP) and luteal (LP) phases may influence energy metabolism in women. We compared fasting energy metabolism and sweet taste preference on a representative day of the FP and LP in twenty healthy women (25·3 (sd 5·1) years, BMI: 22·2 (sd 2·2) kg/m2) with regular self-reported menses and without the use of hormonal contraceptives. From the self-reported duration of the three prior menstrual cycles, the predicted FP and LP visits were scheduled for days 5-12 and 20-25 after menses, respectively. The order of the FP and LP visits was randomly assigned. On each visit, RMR and RQ by indirect calorimetry, sweet taste preference by the Monell two-series forced-choice tracking procedure, serum fibroblast growth factor 21 by a commercial ELISA (FGF21, a liver-derived protein with action in energy balance, fuel oxidation and sugar preference) and dietary food intake by a 24-h dietary recall were determined. Serum progesterone and oestradiol concentrations displayed the expected differences between phases. RMR was lower in the FP v. LP (5042 (sd 460) v. 5197 (sd 490) kJ/d, respectively; P = 0·04; Cohen effect size, d rm = 0·33), while RQ showed borderline significant higher values (0·84 (sd 0·05) v. 0·81 (sd 0·05), respectively; P = 0·07; d rm = 0·62). Also, in the FP v. LP, sweet taste preference was lower (12 (sd 8) v. 16 (sd 9) %; P = 0·04; d rm = 0·47) concomitant with higher serum FGF21 concentration (294 (sd 164) v. 197 (sd 104) pg/ml; P < 0·01; d rm = 0·66). The menstrual cycle is associated with changes in energy expenditure, sweet taste preference and oxidative fuel partitioning.

Free-living competitive racewalkers and runners with energy availability estimates of <35 kcal·kg fat-free mass-1·day-1 exhibit peak serum progesterone concentrations indicative of ovulatory disturbances: a pilot study

Introduction

The release of luteinising hormone (LH) before ovulation is disrupted during a state of low energy availability (EA). However, it remains unknown whether a threshold EA exists in athletic populations to trigger ovulatory disturbances (anovulation and luteal phase deficiency) as indicated by peak/mid-luteal serum progesterone concentration (Pk-PRG) during the menstrual cycle.

Methods

We assessed EA and Pk-PRG in 15 menstrual cycles to investigate the relationship between EA and Pk-PRG in free-living, competitive (trained-elite) Guatemalan racewalkers (n = 8) and runners (n = 7) [aged: 20 (14-41) years; post-menarche: 5 (2-26) years; height: 1.53 ± 0.09 m; mass: 49 ± 6 kg (41 ± 5 kg fat-free mass "FFM")]. EA was estimated over 7 consecutive days within the follicular phase using food, training, and physical activity diaries. A fasted blood sample was collected during the Pk-PRG period, 6-8 days after the LH peak, but before the final 2 days of each cycle. Serum progesterone concentration was quantified using electrochemiluminescence immunoassay.

Results

Participants that reported an EA of <35 kcal·kg FFM-1·day-1 (n = 7) exhibited ovulatory disturbances (Pk-PRG ≤9.40 ng·mL-1). Athletes with EA ≥36 kcal·kg FFM-1·day-1 (n = 8) recorded "normal"/"potentially fertile" cycles (Pk-PRG >9.40 ng·mL-1), except for a single racewalker with the lowest reported protein intake (1.1 g·kg body mass-1·day-1). EA was positively associated with Pk-PRG [r(9) = 0.79, 95% confidence interval (CI): 0.37-0.94; p = 0.003; 1 - β = 0.99] after excluding participants (n = 4) that likely under-reported/reduced their dietary intake.

Conclusions

The result from the linear regression analysis suggests that an EA ≥ 36 kcal·kg FFM-1·day-1 is required to achieve "normal ovulation." The threshold EA associated with ovulatory disturbances in athletes and non-invasive means of monitoring the ovulatory status warrant further research.

The Influence of Energy Balance and Availability on Resting Metabolic Rate: Implications for Assessment and Future Research Directions

Resting metabolic rate (RMR) is a significant contributor to an individual's total energy expenditure. As such, RMR plays an important role in body weight regulation across populations ranging from inactive individuals to athletes. In addition, RMR may also be used to screen for low energy availability and energy deficiency in athletes, and thus may be useful in identifying individuals at risk for the deleterious consequences of chronic energy deficiency. Given its importance in both clinical and research settings within the fields of exercise physiology, dietetics, and sports medicine, the valid assessment of RMR is critical. However, factors including varying states of energy balance (both short- and long-term energy deficit or surplus), energy availability, and prior food intake or exercise may influence resulting RMR measures, potentially introducing error into observed values. The purpose of this review is to summarize the relationships between short- and long-term changes in energetic status and resulting RMR measures, consider these findings in the context of relevant recommendations for RMR assessment, and provide suggestions for future research.

Food preferences throughout the menstrual cycle - A computer-assisted neuro-endocrino-psychological investigation

BACKGROUND

As eating behavior changes in relation to the menstrual cycle and weight changes with menopausal transition, ovarian hormones appear to be involved in regulating eating behavior. However, observations are contradictory and are difficult to compare, due to methodological problems related to nutritional epidemiology. To better understand the relationship between ovarian steroid hormones and eating behavior, our study evaluates women's responses to visual food cues at different points in the menstrual cycle with their specific serum estrogen/progesterone levels and women's responses in the case of strong estrogen changes in the context of fertility treatments.

METHODS

We collected data from 129 women, 44 of whom received in vitro fertilization (IVF) at the Department of Reproductive Endocrinology, University Hospital Zurich. A total of 85 women with natural cycles were recruited at the University Hospital Zurich (n = 37) and at the Hannover Medical School (n = 48). Our observational study used 4 different measurement time points across the natural cycle and 2 measurement time points in women with supraphysiological estradiol levels during fertility treatments. Using a second cycle, we then tested our results for replication. At these predefined time points, women were shown pictures of 11 categories of food, with 4 items for each category and blood samples for measurement of hormone levels were taken. Food preferences registered at the time of the investigation were indicated on a visual analogue scale (0-100).

RESULTS

We did not find any statistically significant association between women's serum hormone levels and the rating of visually presented food, either during the menstrual cycle or during fertility treatments after controlling for multiple testing (all p > 0.005). Ratings for fruits, vegetables, and carbohydrates showed a significant linear decline throughout the first menstrual cycle (p < 0.01), which did not replicate in the second cycle (p > 0.05). In contrast, the ratings for sweets showed a significant linear decline in both cycles (both p < 0.01), with a mean rating of 54.2 and 48.8 in the menstrual phase of the first and second cycle, respectively, to a mean rating of 47.7 and 43.4 in the premenstrual phase of the first and second cycle, respectively. During fertility treatments, no food rating showed a significant change (all p > 0.05). Mood such as negative and positive affects did not influence ratings for visual food cues neither throughout the menstrual cycles nor during fertility treatment.

CONCLUSIONS

Serum levels of estradiol and progesterone do not correlate with food ratings in women, even when estradiol levels are above the physiological level of a natural menstrual cycle. Since, except for sweets, significant changes in food ratings in a first cycle did not replicate in a second menstrual cycle, significant findings from the literature based on animal or human studies focusing on a single-cycle have to be interpreted with caution.

Attentional bias towards appealing and disgusting food cues varies with the menstrual cycle

Ovarian hormonal changes along the female menstrual cycle are believed to adapt women to the external environment through various adaptive strategies, including modulating appetite and eating behavior. We aimed to compare food-associated behavioral responses between two distinct menstrual phases (late follicular vs. mid-luteal) and investigate the underlying neural mechanism. Attentional bias towards visual food cues was repeatedly measured in 29 healthy young women during these two menstrual phases in a counterbalanced manner. Combining an emotional dot-probe task with frequency-tagged electroencephalography (EEG), we confirmed that the menstrual cycle modulated healthy women's attentional bias towards appealing and disgusting food cues. Women in the mid-luteal phase showed more avoidance of disgusting food cues, as reflected by a significantly longer response time. Steady-state visual evoked potential (SSVEP) results indicated that they exhibited a trend of transiently enhanced attentional bias towards appealing food cues and another trend of speeded attentional withdrawal from disgusting food cues during the mid-luteal phase relative to the late follicular phase, albeit non-significant after correction for multiple testing. Moreover, a significantly larger P3 amplitude was evoked by probes following the presentation of disgusting food cues in the mid-luteal phase than the late follicular phase. These findings indicate divergent attentional deployments on emotional food cues across menstrual phases and suggest the mid-luteal phase as a relatively sensitive stage in the menstrual cycle for women to regulate their appetite and eating behavior.

The Validated Features of Psychological Interventions for Weight Loss: An Integration

Many psychological inclinations, such as maladaptive beliefs, can diminish the capacity of individuals to manage their weight effectively and sustainably. Yet, interventions that purportedly address these psychological inclinations and improve weight management are not always beneficial. To be effective, these interventions should offer participants several choices, should be devoid of features that have not been validated in isolation, and should arrange the various activities in an efficient and effective sequence. Few if any programs fulfill these criteria. The aim of this paper was to construct an intervention that assimilates all the validated features of interventions that overcome the psychological impediments to weight loss. To achieve this goal, we blended a technique called intervention component analysis with thematic analysis. Specifically, we extracted refereed journal articles about weight loss from PsycInfo, distilled the practical recommendations from these articles, excluded recommendations that had not been validated in isolation of other features, integrated overlapping recommendations, and applied several principles to arrange these recommendations into the most effective sequence. This procedure generated an intervention that could comprise up to 43 features and activities, including self-affirmation to foster openness to change, anecdotes about dramatic improvements, ambitious rather than modest targets, an emphasis on strategies rather than targets, rewards for attempts, implementation intentions with partners, self-hypnosis, cognitive reframing, and distancing. If these features are unsuccessful, practices that demand more resources-such as group disclosure, virtual environments, motivational interviewing, and customized programs-were also recommended.

Obese Women Have a High Carbohydrate Intake without Changes in the Resting Metabolic Rate in the Luteal Phase

Hormonal changes are caused by the menstrual cycle phases, which influence resting metabolic rate and eating behavior. The aim of the study was to determine resting metabolic rate (RMR) and its association with dietary intake according to the menstrual cycle phase in lean and obese Chilean women. This cross-sectional analytical study included 30 adult women (15 lean and 15 with obesity). Body composition was measured with a tetrapolar bioelectrical impedance meter. Nutritional status was determined by adiposity. A 24-h recall of three nonconsecutive days verifies dietary intake. The RMR was measured by indirect calorimetry. All measurements were performed in both the follicular and luteal phases of the menstrual cycle. Statistical analyses were performed with STATA software at a significance level, which was α = 0.05. The RMR (β = 121.6 kcal/d), temperature (β = 0.36 °C), calorie intake (β = 317.1 kcal/d), and intake of lipids (β = 13.8 g/d) were associated with the luteal phase in lean women. Only extracellular water (β = 1.11%) and carbohydrate consumption (β = 45.2 g/d) were associated in women with obesity. Lean women showed increased RMR, caloric intake, and lipid intake during the luteal phase. For women with obesity, carbohydrate intake increased but not RMR.

Sex Differences Across the Life Course: A Focus On Unique Nutritional and Health Considerations among Women

In the United States, women, while having a longer life expectancy than men, experience a differential risk for chronic diseases and have unique nutritional needs based on physiological and hormonal changes across the life span. However, much of what is known about health is based on research conducted in men. Additional complexity in assessing nutritional needs within gender include the variations in genetics, body compositions, hormonal milieus, underlying chronic diseases, and medication usage, with this list expanding as we consider these variables across the life course. It is clear women experience nutrient shortfalls during key periods of their lives, which may differentially impact their health. Consequently, as we move into the era of precision nutrition, understanding these sex- and gender-based differences may help optimize recommendations and interventions chosen to support health and weight management. Recently, a scientific conference was convened with content experts to explore these topics from a life-course perspective at biological, physiological, and behavioral levels. This publication summarizes the presentations and discussions from the workshop and provides an overview of important nutrition and related lifestyle considerations across the life course. The landscape of addressing female-specific nutritional needs continues to grow; now more than ever, it is essential to increase our understanding of the physiological differences between men and women, and determine how these physiological considerations may aid in optimizing nutritional strategies to support certain personal goals related to health, quality of life, sleep, and exercise performance among women.

Fasting-Mimicking-Diet does not reduce skeletal muscle function in healthy young adults: a randomized control trial

PURPOSE

The aim of this study was to evaluate the short- and long-term effects of the Fasting-Mimicking-Diet (FMD) intervention on neuromuscular parameters of force production in healthy young men.

METHODS

Twenty-four physically active men completed the study. Participants were randomly assigned to Fasting-Mimicking (FMD) or Normal Diet (ND) and asked to follow three cycles of dietary intervention. Neuromuscular parameters of force production during maximal voluntary isometric contractions (MVCs) with the leg extensors muscles and anthropometrics were measured at baseline (T0), at the end of the first cycle (T1), and 7-10 days after the 3rd cycle of the nutritional intervention (T2). The study was registered on Clinicaltrials.gov (No. NCT04476615).

RESULTS

There was a significant decrease in body mass at T1 for FMD (- 2.6 kg, ∆ from baseline, on average; p < 0.05) but not in ND (- 0.1 kg;). Neuromuscular parameters of force production, muscle volume, and MVC torque did not change or differ between groups across visits. Results were similar even when parameters were normalized by muscle volume.

CONCLUSION

The consumption of FMD in a group of young healthy male subjects showed to be feasible, and it did not affect neuromuscular parameters of force production. The results suggest that FMD could be safely adopted by strength athletes without detrimental effects on force and muscle volume. Further research in clinical population at risk of muscle mass loss, such as elderly and obese subjects with sarcopenia, is warranted.

Impact of isoenergetic intake of irregular meal patterns on thermogenesis, glucose metabolism, and appetite: a randomized controlled trial

BACKGROUND

Evidence is emerging that interdaily meal pattern variability potentially affects response such as thermic effect of food (TEF), macronutrient metabolism, and appetite.

OBJECTIVES

To investigate the effect of irregular meal pattern on TEF, glucose, insulin, lipid profile, and appetite regulation in women who are overweight or with obesity and confirmed insulin resistance.

DESIGN

In a randomized crossover trial, 9 women [mean ± SD BMI (in kg/m2): 33.3 ± 3.1] with confirmed insulin resistance consumed a regular (14 d; 6 meals/d) and an irregular (14 d; 3-9 meals/d) meal pattern separated by a 14-d washout interval. Identical foods were provided during the interventions, and at the start and end of each meal pattern, participants attended the laboratory after an overnight fast. Energy expenditure, glucose, insulin, lipids, adiponectin, leptin, glucagon-like peptide 1 (GLP-1), peptide YY (PYY), and ghrelin were measured at baseline and for 3 h after consumption of a test drink, after which an ad libitum test meal was offered. Subjective appetite ratings were recorded before and after the test drink, after the ad libitum meal, and during the intervention. Continuous interstitial glucose monitoring was undertaken for 7 consecutive days during each intervention.

RESULTS

TEF (over 3 h) was significantly lower postirregular intervention compared with postregular (97.7 ± 19.2 kJ*3 h in postregular visit and 76.7 ± 35.2 kJ*3 h in postirregular visit, paired t test, P = 0.048). Differences in HOMA-IR between the 2 interventions (3.3 ± 1.7 and 3.6 ± 1.6 in postregular and postirregular meal pattern, respectively) were not significant. Net incremental AUC for GLP-1 concentrations (over 3 h) for the postregular meal pattern were higher (864.9 ± 456.1 pmol/L*3 h) than the postirregular meal pattern (487.6 ± 271.7 pmol/L*3 h, paired t test, P = 0.005).

CONCLUSIONS

Following a 14-d period of an irregular meal pattern, TEF was significantly less than following a regular meal pattern, potentially compromising weight management if sustained long term. This study was registered at www.clinicaltrials.gov as NCT02582606.

Effect of oral contraceptives on energy balance in women: A review of current knowledge and potential cellular mechanisms

Body weight management is currently of major concern as the obesity epidemic is still a worldwide challenge. As women face more difficulties to lose weight than men, there is an urgent need to better understand the underlying reasons and mechanisms. Recent data have suggested that the use of oral contraceptive (OC) could be involved. The necessity of utilization and development of contraceptive strategies for birth regulation is undeniable and contraceptive pills appear as a quite easy approach. Moreover, OC also represent a strategy for the management of premenstrual symptoms, acne or bulimia nervosa. The exact impact of OC on body weight remains not clearly established. Thus, after exploring the potential underlying mechanisms by which OC could influence the two side of energy balance, we then provide an overview of the available evidence regarding the effects of OC on energy balance (i.e. energy expenditure and energy intake). Finally, we highlight the necessity for future research to clarify the cellular effects of OC and how the individualization of OC prescriptions can improve long-term weight loss management.

The importance of estradiol for body weight regulation in women

Obesity in women of reproductive age has a number of adverse metabolic effects, including Type II Diabetes (T2D), dyslipidemia, and cardiovascular disease. It is associated with increased menstrual irregularity, ovulatory dysfunction, development of insulin resistance and infertility. In women, estradiol is not only critical for reproductive function, but they also control food intake and energy expenditure. Food intake is known to change during the menstrual cycle in humans. This change in food intake is largely mediated by estradiol, which acts directly upon anorexigenic and orexigenic neurons, largely in the hypothalamus. Estradiol also acts indirectly with peripheral mediators such as glucagon like peptide-1 (GLP-1). Like estradiol, GLP-1 acts on receptors at the hypothalamus. This review describes the physiological and pathophysiological mechanisms governing the actions of estradiol during the menstrual cycle on food intake and energy expenditure and how estradiol acts with other weight-controlling molecules such as GLP-1. GLP-1 analogs have proven to be effective both to manage obesity and T2D in women. This review also highlights the relationship between steroid hormones and women's mental health. It explains how a decline or imbalance in estradiol levels affects insulin sensitivity in the brain. This can cause cerebral insulin resistance, which contributes to the development of conditions such as Parkinson's or Alzheimer's disease. The proper use of both estradiol and GLP-1 analogs can help to manage obesity and preserve an optimal mental health in women by reducing the mechanisms that trigger neurodegenerative disorders.

Produced β-hydroxybutyrate after β-hydroxy-β-methylbutyrate (HMB) administration may contribute HMB function in mice

β-Hydroxy-β-methylbutyrate (HMB) is an intermediate in the metabolism of the branched-chain amino acid leucine. HMB has several demonstrated effects on skeletal muscle function, some of which are contradictory. In addition, the effect of exogenous HMB intake on the levels of intermediate metabolites is not known. Therefore, we investigated changes in HMB metabolites after oral HMB administration in mice. First, ICR mice were treated with either distilled water or HMB (0.215 g/10 mL/kg). Sampling was performed at 0, 1, 6, 12, and 24 h after administration. Next, ICR mice were given distilled water or HMB (0.215 g/10 mL/kg/d) for 10 d. Mice given HMB shown a significant increase in liver β-methylcrotonyl-CoA and increased β-hydroxybutyrate in plasma and the gastrocnemius muscle 1 h after HMB administration. Mice administered HMB for 10 d showed significantly decreased food intake and body weight; however, the relative weight of the gastrocnemius muscle was significantly increased. These results may be attributed to an increase in β-hydroxybutyrate resulting from exogenous HMB, since β-hydroxybutyrate inhibits food intake and suppresses skeletal muscle catabolism. In conclusion, β-hydroxybutyrate, a metabolite of HMB, was found to play an important role in the function of HMB.

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β-Hydroxybutyrate levels in plasma and gastrocnemius were enhanced by HMB.

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HMB increases in tissues and plasma returned to original levels within 6 h.

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HMB treatment for 10 d suppressed food intake and decreased body weight.

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Gastrocnemius weight was increased despite deceased body weight in HMB-treated mice.

Hibiscus sabdariffa tea affects diet-induced thermogenesis and subjective satiety responses in healthy men, but not in women: a randomized crossover trial

The aim of this study was to investigate the effect of Hibiscus sabdariffa tea on energy expenditure, satiety response and food intake. This is an open-label, crossover, randomized clinical trial (RBR-5HZ86T), including 21 subjects (11 women, 10 men). The individuals were evaluated at acute moments (fasting and after eating standardized breakfast accompanied by water or Hibiscus sabdariffa tea). Resting energy expenditure was measured by indirect calorimetry, subjective satiety responses were evaluated with a visual analogue scale and food intake was assessed by using food records. The volunteers who drank the Hibiscus sabdariffa tea had lower perception of hunger (p=0.002) and greater feeling of satiety (p=0.010) and fullness (p=0.009) compared to control. Men who ingested the Hibiscus sabdariffa tea had an increase in nitrogen energy expenditure (water: 1501±290.7kcal, Hibiscus sabdariffa tea: 1619±288.9kcal; p=0.029). In comparison to control, men presented less perception of hunger (p=0.003) and desire to eat (p=0.016), increased satiety (p=0.021) and fullness (p=0.010), and women oxidized more fat (p=0.034) when they drank Hibiscus sabdariffa tea. There was no difference between treatments regarding the energy and macronutrient intake from the first meal and throughout the day (p>0.050) for all participants. The Hibiscus sabdariffa tea only affected energy expenditure and satiety responses in men. Clinical trial registry: ReBEC Platform of the Brazilian Clinical Trials Registry - RBR-5HZ86T Novelty bullets • Hibiscus sabdariffa tea promoted an increase in energy expenditure and caused less perception of hunger/desire to eat in men. • Hibiscus sabdariffa tea intake increased postprandial fat oxidation in women.

Association between ketosis and metabolic adaptation at the level of resting metabolic rate

BACKGROUND

The ketone body β-hydroxybutyrate (βHB) has been shown to act as a signaling molecule that regulates metabolism and energy homeostasis during starvation in animal models. A potential association between βHB and metabolic adaptation (a reduction in energy expenditure below predicted levels) in humans has never been explored.

OBJECTIVE

To determine if metabolic adaptation at the level of resting metabolic rate (RMR) was associated with the magnitude of ketosis induced by a very-low energy diet (VLED). A secondary aim was to investigate if the association was modulated by sex.

METHODS

Sixty-four individuals with obesity (BMI: 34.5 ± 3.4 kg/m²; age: 45.7 ± 8.0 years; 31 males) enrolled in a 1000 kcal/day diet for 8 weeks. Body weight/composition, RMR and βHB (as a measure of ketosis) were determined at baseline and week 9 (W9). Metabolic adaptation was defined as a significantly lower measured versus predicted RMR (from own regression model).

RESULTS

Participants lost on average 14.0 ± 3.9 kg and were ketotic (βHB: 0.76 ± 0.51 mM) at W9. A significant metabolic adaptation was seen (-84 ± 106 kcal/day, P < 0.001), with no significant differences between sexes. [βHB] was positively correlated with the magnitude of metabolic adaptation in females (r = 0.432, P = 0.012, n = 33), but not in males (r = 0.089, P = 0.634, n = 31).

CONCLUSION

In females with obesity, but not males, the larger the [βHB] under VLED, the greater the metabolic adaptation at the level of RMR. More studies are needed to confirm these findings and to explore the mechanisms behind the sex difference in the association between ketosis and metabolic adaptation.

TRIAL REGISTRATION NAME

Clinicaltrials.gov.

STUDY REGISTRATION ID

NCT02944253. URL: https://clinicaltrials.gov/ct2/show/NCT02944253.

Influence of Menstrual Cycle or Hormonal Contraceptive Phase on Energy Intake and Metabolic Hormones-A Pilot Study

Sex hormones are suggested to influence energy intake (EI) and metabolic hormones. This study investigated the influence of menstrual cycle (MC) and hormonal contraceptive (HC) cycle phases on EI, energy availability (EA), and metabolic hormones in recreational athletes (eumenorrheic, NHC = 15 and monophasic HC-users, CHC = 9). In addition, 72-h dietary and training logs were collected in addition to blood samples, which were analyzed for 17β-estradiol (E2), progesterone (P4), leptin, total ghrelin, insulin, and tri-iodothyronine (T3). Measurements were completed at four time-points (phases): Bleeding, mid-follicular (FP)/active 1, ovulation (OVU)/active 2, mid-luteal (LP)/inactive in NHC/CHC, respectively. As expected, E2 and P4 fluctuated significantly in NHC (p < 0.05) and remained stable in CHC. In NHC, leptin increased significantly between bleeding and ovulation (p = 0.030) as well as between FP and OVU (p = 0.022). No group differences in other measured hormones were observed across the MC and HC cycle. The mean EI and EA were similar between phases, with no significant differences observed in macronutrient intake over either the MC or HC. While the MC phase might have a small, but statistically significant effect on leptin, the findings of the present study suggest that the MC or HC phase does not significantly alter ad libitum EI or EA in recreational athletes.

Dynamics of Fat Oxidation from Sitting at Rest to Light Exercise in Inactive Young Humans

Societal erosion of daily life low-level physical activity has had a great influence on the obesity epidemic. Given that low fat oxidation is also a risk factor for obesity, we investigated, in a repeated measures design, the dynamics of fat oxidation from a resting state to a light-intensity leg cycling exercise (0–50 watts) in inactive, healthy young adults. Using indirect calorimetry, energy expenditure and the respiratory quotient (RQ) were assessed in a sitting posture at rest and during a cycling exercise in 35 subjects (20 women). The rate of perceived exhaustion (RPE) was assessed using the Borg Scale. During graded leg cycling, the mean RPE did not exceed values corresponding to the exercise being perceived as ‘light’. However, analysis of individual data at 50 watts revealed two distinct subgroups among the subjects: those having RPE values corresponding to the exercise being perceived as ‘very light to light’ and showing no increase in RQ relative to resting levels, as opposed to an increase in RQ in those who perceived the exercise as being ‘somewhat hard to hard’ (p < 0.001). Our study in inactive individuals showing that high fat oxidation was maintained during ‘light-perceived’ physical activity reinforced the potential importance of light physical activity in the prevention of obesity.

Sex differences and considerations for female specific nutritional strategies: a narrative review

Although there is a plethora of information available regarding the impact of nutrition on exercise performance, many recommendations are based on male needs due to the dominance of male participation in the nutrition and exercise science literature. Female participation in sport and exercise is prevalent, making it vital for guidelines to address the sex-specific nutritional needs. Female hormonal levels, such as estrogen and progesterone, fluctuate throughout the mensural cycle and lifecycle requiring more attention for effective nutritional considerations. Sex-specific nutritional recommendations and guidelines for the active female and female athlete have been lacking to date and warrant further consideration. This review provides a practical overview of key physiological and nutritional considerations for the active female. Available literature regarding sex-specific nutrition and dietary supplement guidelines for women has been synthesized, offering evidenced-based practical information that can be incorporated into the daily lives of women to improve performance, body composition, and overall health.

Integrative and quantitative bioenergetics: Design of a study to assess the impact of the gut microbiome on host energy balance

The literature is replete with clinical studies that characterize the structure, diversity, and function of the gut microbiome and correlate the results to different disease states, including obesity. Whether the microbiome has a direct impact on obesity has not been established. To address this gap, we asked whether the gut microbiome and its bioenergetics quantitatively change host energy balance. This paper describes the design of a randomized crossover clinical trial that combines outpatient feeding with precisely controlled metabolic phenotyping in an inpatient metabolic ward. The target population was healthy, weight-stable individuals, age 18-45 and with a body mass index ≤30 kg/m2. Our primary objective was to determine within-participant differences in energy balance after consuming a control Western Diet versus a Microbiome Enhancer Diet intervention specifically designed to optimize the gut microbiome for positive impacts on host energy balance. We assessed the complete energy-balance equation via whole-room calorimetry, quantified energy intake, fecal energy losses, and methane production. We implemented conditions of tight weight stability and balance between metabolizable energy intake and predicted energy expenditure. We explored key factors that modulate the balance between host and microbial nutrient accessibility by measuring enteroendocrine hormone profiles, appetite/satiety, gut transit and gastric emptying. By integrating these clinical measurements with future bioreactor experiments, gut microbial ecology analysis, and mathematical modeling, our goal is to describe initial cause-and-effect mechanisms of gut microbiome metabolism on host energy balance. Our innovative methods will enable subsequent studies on the interacting roles of diet, the gut microbiome, and human physiology.

CLINICALTRIALSGOV IDENTIFIER

NCT02939703. The present study reference can be found here: https://clinicaltrials.gov/ct2/show/NCT02939703.

Food cue-elicited brain potentials change throughout menstrual cycle: Modulation by eating styles, negative affect, and premenstrual complaints

BACKGROUND

While there is evidence for increased food intake and craving during the luteal phase, underlying mechanisms are incompletely understood. The present study investigated electrophysiological responses to food pictures as a function of menstrual cycle phase. In addition, the moderating effects of progesterone, eating behaviors (restraint, emotional, orthorexic), negative affect, and premenstrual complaints were explored.

METHODS

Using a within-subject design, 35 free-cycling women watched and rated pictures of food (high and low caloric) and control items during the follicular, the ovulatory, and the luteal phase (counterbalanced), while EEG was recorded to examine the late positive potentials (LPP). Salivary gonadal hormones and affect were examined at each occasion. Eating behaviors and premenstrual complaints were assessed once.

RESULTS

For parietal regions, average LPPs were comparable between cycle phases but slightly larger LPP amplitudes were elicited by high caloric food pictures as compared to the neutral category. Descriptively, both food categories elicited larger parietal LPPs than neutral pictures during the luteal phase. Analyses of LPPs for central-parietal regions showed no effect of picture category or cycle phase, except higher amplitudes in the right area during the luteal phase. During the luteal phase, progesterone and functional interference from premenstrual symptoms (but not age, BMI, picture ratings, affect, estradiol, or eating behaviors) significantly predicted larger parietal LPPs towards high caloric (but not low caloric) pictures.

CONCLUSION

Our findings suggest a heightened food cue reactivity during the luteal phase, which may relate to higher ovarian hormone secretion and more functional impact of premenstrual symptoms. This research contributes to a better understanding of menstrual health and the identification of preventive strategies for premenopausal women.

Impact of Combined Hormonal Contraceptive Use on Weight Loss: A Secondary Analysis of a Behavioral Weight-Loss Trial

OBJECTIVE

This study aimed to perform a preliminary investigation of the impact of combined hormonal contraceptive (CHC) use on weight loss during an 18-month behavioral weight-loss trial.

METHODS

Adults (n = 170; 18-55 years; BMI 27-42 kg/m² ) received a weight-loss intervention that included a reduced-calorie diet, a progressive exercise prescription, and group-based behavioral support. Premenopausal women (n = 110) were classified as CHC users (CHC, n = 17) or non-CHC users (non-CHC, n = 93). Changes in weight were examined within groups using a linear mixed model, adjusted for age and randomized group assignment.

RESULTS

At 6 M, weight was reduced from baseline in both CHC (mean, -6.7 kg; 95% CI: -9.8 to -3.7 kg) and non-CHC (-9.1 kg; -9.1 to -6.4 kg). Between 6 and 18 M, CHC regained weight (4.9 kg; 0.9 to 8.9 kg), while weight remained relatively unchanged in non-CHC (-0.1 kg; -1.8 to 1.6 kg). At 18 M, weight was relatively unchanged from baseline in CHC (-1.8 kg; -7.3 to 3.6 kg) and was reduced from baseline in non-CHC (-7.9 kg; -10.2 to -5.5 kg).

CONCLUSIONS

In this secondary data analysis, CHC use was associated with weight regain after initial weight loss. Prospective studies are needed to further understand the extent to which CHC use influences weight loss and maintenance.

HD-FFQ to Detect Nutrient Deficiencies and Toxicities for a Multiethnic Asian Dialysis Population

A rapid and reliable tool appropriate to quantifying macronutrient and micronutrient intakes in diets consumed by Malaysian hemodialysis (HD) patients is lacking. We aimed to develop and validate a novel HD-food frequency questionnaire (HD-FFQ) to assess habitual nutritional intakes of HD patients with diverse ethnic backgrounds. This study was conducted in three phases. In Phase I, a HD-FFQ comprising 118 food items was developed using 3-day diet recalls (3DDR) from 388 HD patients. Phase II was the face and content validation using the Scale-Content Validity Index (S-CVI). After successfully developing the FFQ, Phase III tested relative validation against a reference method, the 3DDR. Results from Phase III showed that the mean difference for absolute intakes of nutrients assessed by HD-FFQ and 3DDR were significant (p < 0.05). However, there was a significant correlation between the HD-FFQ and reference method ranging from 0.35–0.47 (p < 0.05). Cross-quartile classification showed that <10% of patients were grossly misclassified. In conclusion, the HD-FFQ has an acceptable relative validity in assessing and ranking the dietary intake of the HD patients in Malaysia.

Why young women gain weight: A narrative review of influencing factors and possible solutions

Significant weight gain occurs in women during young adulthood, which increases risk of diseases such as diabetes, cardiovascular disease, and many cancers. This review aims to inform future individually targeted weight gain prevention programmes and summarizes possible targets: key life events, mediators that influence energy intake and physical activity levels, and moderators that could identify groups of women at greatest risk. Life events affecting weight include pregnancy and motherhood, smoking cessation, marriage and cohabiting, attending university, and possibly bereavement. Research has identified successful methods for preventing weight gain associated with pregnancy and motherhood, which could now be used in practice, but evidence is inconclusive for preventing weight gain around other life events. Weight gain is mediated by lack of knowledge and skills around food and nutrition, depression, anxiety, stress, satiety, neural responses, and possibly sleep patterns and premenstrual cravings. A paucity of research exists into altering these to limit weight gain. Moderators include socioeconomic status, genetics, personality traits, and eating styles. More research is required to identify at-risk females and engage them in weight gain prevention. There is a need to address evidence gaps highlighted and implement what is currently known to develop effective strategies to limit weight gain in young women.

Rate of inappropriate energy and micronutrient intake among the Korean working population

OBJECTIVE

Adequate energy and nutrient intakes are important for workers who spend at least one-third of their day working. We investigated differences in these intakes among Korean workers because few studies have reported on energy or nutrient intakes, related to working conditions (long working hours, shift work and non-standard work).

DESIGN

Dietary intake was assessed using 1-d 24-h recall. Energy and nutrient intakes were evaluated using age- and sex-specific dietary reference intakes for Korean citizens. Occupational characteristics were obtained from self-reported Korean National Health and Nutritional Examination Survey (KNHANES) data (occupational classification, working hours, shift work and non-standard workers). An age, education and household income-adjusted logistic regression model was applied to investigate differences in inappropriate energy and nutrient intakes, by sex and occupation.

SETTING

Cross-sectional study.

PARTICIPANTS

From KNHANES (2007-2016), 11 145 participants (5401 males; 5744 females) were included, finally.

RESULTS

Males with long working hours had higher inappropriate carbohydrate, protein, water, vitamin B2 and phosphate intakes than those who worked ≤60 h/week. Long working hours among females were significantly associated with total energy and nutrient 'under-intake'. Male shift and non-standard workers had higher inappropriate protein, water, mineral and vitamin intakes. Multivariate logistic regression revealed that white- and male pink-collar workers had significantly increased risks of water and vitamins A, C, B1 and niacin 'under-intake'.

CONCLUSIONS

We found different rates of inappropriate energy and micronutrient intakes according to working conditions. Younger workers with long hours and shift work schedules were vulnerable to inappropriate energy and nutrient intakes.

Dietary Patterns in New Zealand Women: Evaluating Differences in Body Composition and Metabolic Biomarkers

The combinations of food consumed together (dietary patterns) may have a greater influence on health than nutrients or food groups consumed independently. This study investigated the relationship between dietary patterns, body composition and metabolic biomarkers of premenopausal New Zealand women from three ethnic groups. In total, 408 New Zealand European, Māori and Pacific women aged 16-45 years participated in the Women's EXPLORE (EXamining Predictors Linking Obesity Related Elements) study. Participants completed a 220-item food frequency questionnaire. Several body composition parameters and metabolic biomarkers were measured. Dietary patterns were extracted by principal component analysis and dietary pattern scores were categorised into tertiles to assess links with other measured parameters. Women with higher scores for the 'refined and processed' pattern were younger, had higher body mass index, total body fat, plasma leptin and plasma insulin (p < 0.001), and lower plasma ghrelin levels (p < 0.05) than women with lower scores. In addition, more Māori (51%) and Pacific (68%) women followed the 'refined and processed' pattern, while more New Zealand European women (40%) followed the 'sweet and savoury snacking' pattern. These data show that dietary pattern analysis is a useful tool to assess links between diet and metabolic health. It further reveals interesting ethnic group-specific differences in dietary pattern use.

Validity of Self-Reported Body Mass, Height, and Body Mass Index in Female Students: The Role of Physical Activity Level, Menstrual Cycle Phase, and Time of Day

A large part of research using questionnaires for female university students relies on self-reported body mass, height, and body mass index (BMI) data; however, the validity of these data in this population group is unknown. Therefore, the aim of the present study is to examine the validity of self-reported body mass, height, and BMI in female students. Female students of biomedical sciences (n = 93, age 21.8 ± 4.7 years, height 1.63 ± 0.06 m, weight 60.5 ± 11.9 kg, and BMI 22.7 ± 3.8 kg/m²) completed the short version of the International Physical Activity Questionnaire and were tested for anthropometric characteristics at three different times of the day (12–2 p.m., n = 36; 2–4 p.m., n = 20; 4–6 p.m., n = 37). Participants over-reported height (+0.01 ± 0.02 m, +0.9 ± 1.2%, Cohen’s d = 0.22) and under-reported weight (−0.8 ± 2.1 kg, −1.2 ± 3.6%, d = −0.07) and BMI (−0.7 ± 1.0 kg/m², −2.9 ± 4.2%, d = −0.19) (p < 0.001). A moderate main effect of time of day on %Δweight (p = 0.017, η² = 0.086) and %ΔBMI (p = 0.045, η² = 0.067), but not on %Δheight (p = 0.952, η² = 0.001), was observed, where the group tested at 4–6 p.m. under-reported weight and BMI more than the 2–4 p.m. group. The weekly metabolic equivalent (MET) × min did not correlate with %Δheight (r = 0.06, p = 0.657), but its correlations with %Δweight (r = −0.27, p = 0.051) and %ΔBMI (r = −0.238, p = 0.089) reached statistical significance. Participants in the early follicular phase reported BMI more accurately (p = 0.084, d = 0.68) than those in the mid-luteal phase. In conclusion, female students over-reported height and under-reported weight and BMI. Under-reporting weight and BMI is influenced by time of day and menstrual cycle phase. These findings should be considered by health professionals and researchers when administering questionnaires to female students.

Assessment of Dietary Intake, Energy Status, and Factors Associated With RED-S in Vocational Female Ballet Students

Elite ballet dancers are at risk of health issues associated with Relative Energy Deficiency in Sport (RED-S). This study determined the nutritional status, estimated energy status, and assessed factors related to RED-S in vocational female ballet students. Using a cross-sectional study design, we measured dietary intake (food diaries and 24 h dietary-recall) and energy expenditure (accelerometry) in vocational female ballet students (n = 20; age: 18.1 ± 1.1 years; body mass index: 19.0 ± 1.6 kg·m²; body fat: 22.8 ± 3.4%) over 7 days, including 5 weekdays (with dance training) and 2 weekend days (without scheduled dance training). Furthermore, we assessed eating behaviors, menstrual function, risk of RED-S (questionnaires), and body composition (dual x-ray absorptiometry). Energy and macronutrient intakes of vocational ballet students were similar during weekdays and weekend days (P > 0.050), whereas total energy expenditure was greater on weekdays than weekend days (P < 0.010; 95% CI: 212, 379). Energy balance was lower on weekdays (-425 ± 465 kcal·day^-1) than weekend days (-6 ± 506 kcal·day^-1, P = 0.015; 95% CI: -748, -92). Exercise energy expenditure was greater on weekdays (393 ± 103 kcal·day^-1) than weekend days (213 ± 129 kcal·day^-1; P < 0.010; 95% CI: 114, 246), but energy availability was similar between time periods (weekdays 38 ± 13 kcal·kg FFM·day^-1; weekend days 44 ± 13 kcal·kg FFM·day^-1; P = 0.110). Overall, 35% of participants had an energy intake <1,800 kcal·day^-1, 44% had reduced energy availability (30-45 kcal·kg FFM·day^-1), and 22% had low energy availability (<30 kcal·kg FFM·day^-1). Menstrual dysfunctions were reported in 40% of participants; 15 and 25% reported oligomenorrhea and secondary amenorrhea, respectively; while 65% were classified at risk of RED-S (based on the Low Energy Availability in Females Questionnaire). All participants had adequate bone health (bone mineral density Z-score: 1.1 ± 0.9 SD), but 20% had <85% expected body weight. The observation of an energy deficit in vocational female ballet students was primarily attributed to an inability to plan energy intake and thereby meet higher energy requirements during ballet training weekdays. Screening for factors associated with RED-S and tailoring education programs to inform energy and nutrition requirements for health and training are recommended in elite young ballet students.

Menstrual History-Taking at Annual Well Visits for Adolescent Girls

STUDY OBJECTIVE

To determine the rates at which primary care providers elicit menstrual histories from adolescent girls at well visits.

DESIGN

Retrospective chart review.

SETTING

The departments of Pediatrics, Adolescent Medicine, and Family Medicine of Cooper University Healthcare from January 1, 2010 to June 1, 2016.

PARTICIPANTS

Women aged 12-21 years who were seen for a well visit in the described setting.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

We searched physician well visit notes for documentation of the following aspects of menstrual history: menarche, last menstrual period, usual length of cycle, and the presence or absence of associated symptoms (such as pain and cramps). The presence or absence of each aspect was recorded in a binary fashion in a deidentified data set.

RESULTS

A total of 954 unique charts were analyzed: 415 from Adolescent Medicine, 289 from Family Medicine, and 250 from General Pediatrics at Cooper University Healthcare. Adolescent Medicine was 6.44 times more likely to take a complete menstrual history than Family Medicine (P < .0001) and 5.80 times more likely than Pediatrics (P < .0001). There was no statistical difference between Pediatrics and Family Medicine (odds ratio, 0.55; P = .3150).

CONCLUSION

Menstrual history-taking is often incomplete and can vary between departments, even within the same institution. These results indicate opportunities to raise awareness about the importance of a complete menstrual history and to develop quality improvement initiatives to increase documentation of the complete menstrual history.

Weight Loss and Appetite Control in Women

PURPOSE OF REVIEW

The aim of this review is to describe and discuss weight loss-induced variations in appetite in women and factors responsible for these changes.

RECENT FINDINGS

Studies have shown postweight loss increases in fasting and postprandial appetite in individuals engaged in weight loss trials, especially in women. Similarly, appetite-related peptides associated to the homeostatic control of feeding, such as leptin, ghrelin and peptide YY, were also found to be altered in way that promotes increased appetite after weight loss interventions. Sustained caloric deficits also drive increases in the frequency and strength of food cravings, food reward and seem to enhance oro-sensory sensations in women who lost weight. The menstrual cycle has also been to shown to influence caloric intake in women, more specifically food cravings. On the other hand, caloric restriction seems to increase cognitive restraint, decrease habitual disinhibition and susceptibility to hunger among women engaged in weight loss trials. Neural analysis corroborates these results, showing increased activation in brain areas involved in food reward and self-control processing. In conclusion, evidence supports that weight loss increases appetite sensations, and promotes changes in homeostatic and non-homeostatic control of feeding, which collectively seem to upregulate appetite in women.

Depressive Symptoms During Adolescence Predict Adulthood Obesity Among Black Females

AIM

This study aimed to investigate gender differences in the association between baseline depressive symptoms and subsequent changes in obesity in a sample of urban Black youth in the USA.

METHODS

The current study followed 681 Black youth (335 male and 346 female) for up to 18 years from 1994 to 2012. All youth were selected from an economically disadvantaged urban area in MI, USA. The main independent variable was baseline depressive symptoms measured in 1994. The main outcome was change in body mass index (BMI) from 1999 to 2012, calculated based on self-reported height and weight. Scio-demographics (age, number of parents in the household, and parental employment) were covariates. Gender was the focal moderator. We used linear regressions to test the predictive role of baseline depressive symptoms on change in BMI (from 1999 to 2012) in the pooled sample, and also based on gender.

RESULTS

Among Black females, but not Black males, baseline depressive symptoms predicted the BMI change from 1999 to 2012. The association remained significant for Black females after controlling for covariates.

CONCLUSION

High depressive symptoms at baseline better predict BMI change over the next decade for female than male Black youth. As a result, detection and reduction of depressive symptoms may be a vital element of obesity prevention programs for Black females. Policies and programs that address determinants of psychological distress as a strategy to prevent obesity among female Black youth in disadvantaged neighborhoods may be especially useful.

Does a single bout of exercise influence subsequent physical activity and sedentary time in overweight boys?

OBJECTIVE

To assess the influence of a single bout of exercise on subsequent physical activity and sedentary time among overweight boys.

METHODS

A crossover study on 24 overweight boys (11-13years old) was conducted with three different experimental sessions: control, one bout of moderate exercise, and one bout of vigorous exercise. Physical activity was measured using triaxial accelerometers and time spent in light, moderate, vigorous, and sedentary activities was assessed during six days of follow-up. Differences in daily percentage of time spent in sedentary, light, moderate, and vigorous activities among experimental sessions were analyzed using linear mixed-effect models.

RESULTS

Time spent in sedentary behavior was greater after moderate and vigorous sessions compared to the control, with statistically significant differences in trajectories between moderate (p=0.04) and vigorous sessions (p=0.006) compared to controls. Similarly, the time spent in moderate physical activity was smaller after moderate (p=0.02) and vigorous sessions (p=0.02) compared to the control. No differences in sedentary (p=0.50) and moderate (p=0.97) activities were observed between moderate and vigorous sessions. The percentage of time spent in vigorous physical activity showed a greater reduction in vigorous condition compared to moderate and control (p<0.01) conditions, while time spent in light physical activities was not different between sessions.

CONCLUSIONS

Our results indicate a compensatory effect after a single bout of exercise due to decreases in moderate and vigorous physical activity and increases in sedentary time during the following six days.

Energy intake and energy expenditure of pre-professional female contemporary dancers

Many athletes in aesthetic and weight dependent sports are at risk of energy imbalance. However little is known about the exercise and eating behaviours of highly trained dance populations. This investigation sought to determine the energy intake and energy expenditure of pre-professional female contemporary dancers. Twenty-five female contemporary dance students completed the study. Over a 7-day period, including five week days (with scheduled dance training at a conservatoire) and two weekend days (with no scheduled dance training at the conservatoire), energy intake (self-reported weighed food diary and 24 h dietary recall) and expenditure (tri-axial accelerometry) were recorded. Mean daily energy intake and expenditure were different over the 7-day period (P = 0.014) equating to an energy deficit of -356 ± 668 kcal·day-1 (or -1.5 ± 2.8 MJ·day-1). Energy expenditure was not different when comparing week and weekend days (P = 0.297). However daily energy intake (P = 0.002), energy availability (P = 0.003), and energy balance (P = 0.004) were lower during the week compared to the weekend, where energy balance became positive. The percentage contribution of macronutrients to total energy intake also differed; with higher fat (P = 0.022) and alcohol (P = 0.020), and lower carbohydrate (P = 0.001) and a trend for lower protein (P = 0.051) at the weekend. Energy balance and appropriate macronutrient intake are essential for maintaining the demands of training, performance and recovery. Whilst aesthetics are important, female contemporary dancers may be at risk of the numerous health and performance impairments associated with negative energy balance, particularly during periods of scheduled training.

Sex differences in the response of total PYY and GLP-1 to moderate-intensity continuous and sprint interval cycling exercise

BACKGROUND

Exercise interventions are often less effective at improving body composition for females than males, potentially due to post-exercise hormonal responses that increase energy intake in females. Recently, sprint interval training was shown to effectively reduce body fat in females despite being relatively low during exercise energy expenditure.

PURPOSE

To determine whether any sex difference in total PYY, GLP-1 or perceived hunger exists following moderate-intensity continuous exercise (MICT) and sprint interval exercise (SIT) METHODS: Twenty-one active participants (11 females) participated in three sessions in a randomized crossover design: (1) MICT, 30-min cycling at 65% VO_2max; (2) SIT, 6 × 30 s "all-out" sprints with 4-min recovery periods; (3) control (CTRL; no exercise). Blood samples were collected pre-exercise, immediately and 90 min post-exercise for the measurement of total PYY and GLP-1. Subjective perceptions of hunger were assessed using a visual analogue scale pre-breakfast and before all blood samples.

RESULTS

Concentrations of total PYY and GLP-1 were greater during MICT (P = 0.05) and SIT (P = 0.005) compared to CTRL. Total PYY increased more immediately post-exercise in males than females (P = 0.030). GLP-1 only increased in females following MICT (P = 0.034) and SIT (P = 0.024) compared to CTRL. Perceived hunger was lower immediately post-MICT (P = 0.016) and SIT (P = 0.006) compared to CTRL.

CONCLUSIONS

These results suggest that total PYY and GLP-1 respond differently to exercise in males and females over 90 min following various exercise intensities. The observed post-exercise hormonal response would not be expected to create a compensatory increase in energy intake in females.

Glial cells and energy balance

The search for new strategies and drugs to abate the current obesity epidemic has led to the intensification of research aimed at understanding the neuroendocrine control of appetite and energy expenditure. This intensified investigation of metabolic control has also included the study of how glial cells participate in this process. Glia, the most abundant cell type in the central nervous system, perform a wide spectrum of functions and are vital for the correct functioning of neurons and neuronal circuits. Current evidence indicates that hypothalamic glia, in particular astrocytes, tanycytes and microglia, are involved in both physiological and pathophysiological mechanisms of appetite and metabolic control, at least in part by regulating the signals reaching metabolic neuronal circuits. Glia transport nutrients, hormones and neurotransmitters; they secrete growth factors, hormones, cytokines and gliotransmitters and are a source of neuroprogenitor cells. These functions are regulated, as glia also respond to numerous hormones and nutrients, with the lack of specific hormonal signaling in hypothalamic astrocytes disrupting metabolic homeostasis. Here, we review some of the more recent advances in the role of glial cells in metabolic control, with a special emphasis on the differences between glial cell responses in males and females.

Change in women's eating habits during the menstrual cycle

OBJECTIVES

During the menstrual cycle, the influence of hormonal variations on dietary habits in women has been suggested by several studies. In this context, our work aimed to assess the spontaneous food intake and the anthropometric parameters of women at different periods of their menstrual cycles.

METHODS

This prospective study included 30 healthy women with regular periods (28 to 30 days), aged between 18 and 45. We assessed the spontaneous food intake and the anthropometric measurements (weight and waist circumference) of the participants, during the follicular, peri-ovulatory and luteal phases of their menstrual cycles.

RESULTS

Our results showed a slight but significant increase in body weight during the luteal phase (P=0.022) and the follicular phase (P=0.017) compared with the peri-ovulatory phase, without any significant change in waist circumference. The caloric intake increased during the peri-ovulatory (P<0.001) and the luteal phases (P<0.001), compared with the follicular phase, with a significant increase in carbohydrate (P<0.001), lipid (P=0.008) and protein (P=0.008) intake.

CONCLUSIONS

Our study showed a significant decrease in women's weight during the peri-ovulatory phase, with a significant increase in caloric intake during the luteal phase of the menstrual cycle. Divergent results have been reported by other authors and the physiopathology of these changes is still poorly understood.

Estradiol, SHBG and leptin interplay with food craving and intake across the menstrual cycle

OBJECTIVE

To understand the association between ovarian hormones, non-acute satiety hormones and craving calorie dense foods in the luteal phase.

METHODS

17 premenopausal women, mean age 23.2 y, mean BMI 22.4kg/m(2) with regular menstrual cycles were studied during late follicular (FP) and luteal phases (LP). Estradiol, progesterone, DHEAS, SHBG, insulin and leptin, were measured in fasting samples. The validated Food Craving Inventory was used to record the types of foods volunteers habitually ate - rich in fat, carbohydrate or sweet taste, as well as craved during the LP of their menstrual cycle.

RESULTS

Estradiol was inversely associated with leptin in FP (r=-0.62, p=0.01). Leptin was inversely associated with habitual intake of sweet foods, in both phases (FP: r=-0.64, p=0.01; LP: r=-0.63, p=0.01). SHBG in LP was positively associated with craving sweet and carbohydrate rich foods. Hierarchical cluster analysis revealed two groups of women, one with high estradiol, high estradiol/leptin ratio, high sweet and carbohydrate cravings (p<0.05); the other group had lower estradiol, lower estradiol/leptin ratio, and reported less craving.

CONCLUSIONS

The estradiol-leptin axis may be a determinant of luteal phase craving and habitual food intake in menstruating women.

CLINICAL TRIAL REGISTRATION NUMBER

NCT01407692.

Irregular meal-pattern effects on energy expenditure, metabolism, and appetite regulation: a randomized controlled trial in healthy normal-weight women

BACKGROUND

Obesity is increasing in parallel with greater all-day food availability. The latter may promote meal irregularity, dysregulation of the energy balance, and poor metabolic health.

OBJECTIVE

We investigated the effect of meal irregularity on the thermic effect of food (TEF), lipid concentrations, carbohydrate metabolism, subjective appetite, and gut hormones in healthy women.

DESIGN

Eleven normal-weight women (18-40 y of age) were recruited in a randomized crossover trial with two 14-d isoenergetic diet periods (identical foods provided and free living) that were separated by a 14-d habitual diet washout period. In period 1, participants followed a regular meal pattern (6 meals/d) or an irregular meal pattern (3-9 meals/d), and in period 2, the alternative meal pattern was followed. Before and after each period, when participants were fasting and for 3 h after intake of a test drink, measurements were taken of energy expenditure, circulating glucose, lipids (fasting only), insulin, glucagon-like peptide 1 (GLP-1), peptide YY (PYY), and ghrelin. An ad libitum test meal was offered. Subjective appetite ratings were assessed while fasting, after the test drink, after the ad libitum meal, and during the intervention. Continuous interstitial glucose monitoring was undertaken for 3 consecutive days during each intervention, and the ambulatory activity pattern was recorded (ambulatory energy expenditure estimation).

RESULTS

Regularity was associated with a greater TEF (P < 0.05) and a lower incremental area under the curve (iAUC) for glucose after intake of the test drink (over 3 h) and, for some identical meals, during the 2 interventions (over 90 min) (day 7: after breakfast; day 9: after lunch and dinner). There was no difference between treatments for the test-drink gut hormone response. A time effect was noted for fasting GLP-1, fasting PYY, PYY responses, and hunger-rating responses to the test drink (P < 0.05). Lower hunger and higher fullness ratings were seen premeal and postmeal during the regular period while subjects were free living.

CONCLUSION

Meal regularity appears to be associated with greater TEF and lower glucose responses, which may favor weight management and metabolic health. This trial was registered at clinicaltrials.gov as NCT02052076.

A weight-loss program adapted to the menstrual cycle increases weight loss in healthy, overweight, premenopausal women: a 6-mo randomized controlled trial

BACKGROUND

Hormonal fluctuations during the menstrual cycle influence energy intake and expenditure as well as eating preferences and behavior.

OBJECTIVE

We examined the effect in healthy, overweight, premenopausal women of a diet and exercise weight-loss program that was designed to target and moderate the effects of the menstrual cycle compared with the effect of simple energy restriction.

DESIGN

A total of 60 healthy, overweight, premenopausal women were included in a 6-mo weight-loss program in which each subject consumed a diet of 1600 kcal/d. Subjects were randomly assigned to either a combined diet and exercise program that was tailored to metabolic changes of the menstrual cycle (Menstralean) or to undergo simple energy restriction (control).

RESULTS

Thirty-one women (19 Menstralean and 12 control women) completed the study [mean ± SD body mass index (in kg/m(2)): 32.0 ± 5.2]. Both groups lost weight during the study. In an intention-to-treat analysis, the Menstralean group did not achieve a clinically significant weight loss compared with that of the control group (P = 0.61). In per-protocol analyses, a more-pronounced weight loss of 4.3 ± 1.4 kg (P = 0.002) was shown in adherent Menstralean subjects than in the control group.

CONCLUSION

A differentiated diet and exercise program that is tailored to counteract food cravings and metabolic changes throughout the menstrual cycle may increase weight loss above that achieved with a traditional diet and exercise program in women who can comply with the program. This trial was registered at clinicaltrials.gov as NCT01622114.

Clinical Management of Obesity in Women: Addressing a Lifecycle of Risk

The World Health Organization estimates that nearly 2 billion people worldwide are overweight, 600 million of whom are obese. The increasing prevalence of this condition in women is of particular concern given its impact on reproductive health and mortality. Burgeoning data implicating maternal obesity in fetal programming and the metabolic health of future generations further suggest that obesity in women is one of the most pressing public health concerns of the twenty-first century. However, health care professionals are infrequently engaged in obesity management. This article provides a conceptual understanding of obesity and a rational approach to treatment.

Levels of Adipokines and Some Steroids During the Menstrual Cycle

The cyclical effects of hormones during the menstrual cycle (MC) are not just responsible for driving ovulation, but also have significant influence on dietary intake and appetite, as well as psychological and behavioral changes. The aim of our study was to describe changes and relationships between the MC and selected steroids, adipokines and food intake-related hormones. Twenty-seven women with regular menstrual cycles were included in the study, and their hormonal spectrum was measured in regular intervals starting from the first day of their cycle. Classical changes in gonadotropins, estrogens and progesterone during the menstrual cycle are accompanied by less striking but significant changes in 17-hydroxyprogesterone and testosterone. No significant changes show dehydroepiandrosterone and its 7-oxygenated metabolites. Adipokines show a tendency to increase during ovulation, while ghrelin and resistin decrease. There is also a remarkable association of sex hormone-binding globulin on the day of the cycle. Our results demonstrate that changes to adipokines during the menstrual cycle are not substantial, but nonetheless can play a role in the changes of food intake described in the literature. Precise descriptions of physiological changes in healthy women are important in helping us understand the significance of the changes accompanying various pathological states.