Independent effects of 7-days imposed exercise on free-living energy balance and appetite-regulating hormones in males

A thesis submitted to the University of Bedfordshire, in fulfilment of the requirements for the degree of Masters of Science by Research at the Institute for Sport and Physical Activity Research (ISPAR).Study 1 examined the reliability of a photographic food diary (with additional written details) on free-living energy intake (EI) in 13 healthy males. Daily average EI did not differ significantly between two, 7-day periods (p = 0.116) but a large systematic bias (143 ± 715 kcal.day-1) and wide limits of agreement (LoA) (-1258 to 1545 kcal.day-1) were found. Study 2 examined the influence of imposed exercise (7 days) on energy balance and the acylated ghrelin and total PYY response to a meal. Five healthy males completed two, 7-day trials in a crossover randomised design: no exercise (N-EX) and exercise (EX; ~69% V\u101236 O2peak expending an average 815 kcal.day-1). EI and EE were assessed throughout each trial. Blood and appetite ratings (visual analogue scales; VAS) were collected the day prior to and 70 hours post each trial (fasting and for 3 hours postprandial; a final VAS after an ad libitum meal). Exercise significantly increased EI by 27% (p = 0.005), although participants remained in an energy deficit. Appetite regulating hormones and appetite ratings did not alter from pre- to 70 hours post-intervention. Thus, 7-days of imposed exercise induced a partial compensation through EI, without changes in appetite hormones or appetite ratings

Psychometric properties of the Multiple Eating Antecedents Scale (MEAL): A behavioral assessment instrument for measuring diet nonadherence in diabetes mellitus.

The Multiple Eating Antecedent Scale (MEAL) is a behavioral instrument used to measure diet nonadherence in people with diabetes mellitus. The current study was conducted to gather additional reliability and validity indicators of the MEAL. A prospective design was used to measure diet, blood glucose, stress and adherence in 38 adults with blood Type I and Type II diabetes mellitus for four consecutive days. Comparisons were made between self-monitoring data and MEAL scores. In addition MEAL category scores were compared to established diabetes-specific questionnaires as a measure of MEAL validity. Results indicated that the MEAL has good one week test-retest reliability and appears to have good convergent validity with other diabetes-specific questionnaires and some of the self-monitoring data. Diet self-monitoring data and self-reported stress were less strongly associated with MEAL scores. Implications of these findings and directions for future refinement and use of the MEAL are discussed

THE EFFECTS OF INTERMITTENT FASTING AND A HIGH PROTEIN DIET IN INDIVIDUALS WITH TYPE 2 DIABETES MELLITUS

Intermittent fasting (IF) is a recently popularized meal timing strategy whereby individuals abstain continuously from any energy intake for 16 to 20 hours each day, subsequently condensing energy intake into a short period spanning 4 to 8 hours. We aimed to test the effects of intermittent fasting in 10 individuals with Type 2 Diabetes Mellitus in conjunction with recommendations to consume a high protein diet in a 6 to 8 week withdrawal study. This study consisted of three phases: baseline, intervention, and follow-up. During the 2-week baseline and intervention phases participants consumed meals at regular times. Biochemical, anthropometric, and physical activity measurements were taken at the end of each phase. Participants reported morning, afternoon and evening self-monitored blood glucose and fasting duration on a daily basis, in addition to completing a remote food photography diary three times within each study phase. Despite the short duration of the intervention phase, intermittent fasting led to significant decreases in weight, BMI, morning SMBG, and overall reductions in waist circumference, C-reactive protein, energy intake, carbohydrate intake, and fat intake. There were significant variations between participants in response to intermittent fasting in respect to changes in lipids and insulin sensitivity, which could not be explained by baseline biochemical or anthropometric measures, fasting duration, energy intake, or physical activity. Upon cessation of intermittent fasting, biochemical changes regressed towards baseline values during the follow-up period. Intermittent fasting was well tolerated by most participants, and no severe adverse events were noted. Morning nausea was the most common complaint, which abruptly ceased when medication timing was changed

Weight Loss Apps : Behavioral and Psychological Factors Related to Usage and Success

Mobile weight loss applications (‘apps’) such as MyFitnessPal® and Lose It!® have millions of downloads and allow users to track their intake on the go by accessing a massive digital nutrition database, and while the apps have been successful tools for participants in structured weight loss initiatives, little research has explored their efficacy for stand-alone users. The aim of this study was to examine the role of user adherence behavior, portion estimation and consumption norms, and the potential for the app to act as a behavior change tool. An online survey was administered to individuals 18 years or older who have used either MyFitnessPal or Loselt! in order to assess frequency of use, completeness of food records, portion estimation ability, portion consumption norms, and qualitative feedback on factors that impact user experience. Data was gathered using Qualtrics Survey Software and analyzed in IBM SPSS Statistics 22.0 using correlations, t-tests, ANOVA, ANCOYA, and linear regressions. Qualitative data was analyzed through coding and emergence of themes. Fully adherent groups lost significantly more weight than less adherent groups when controlling for duration of usage, and overall, adherence and duration predicted 40% of Average Total Completeness (p\u3c0.01). Participants displayed poor estimation skills, overestimating portion size by an average of 77.54%. Portion norms were not significantly related to weight loss but were positively related to Portion Estimation Error (p\u3c0.01). Qualitative analysis revealed four major themes that influence and explain user experience: App Features, App Qualities, Social Components, and the App as a Behavior Change Tool. Overall, these findings indicate that apps have the potential to be highly effective methods of behavior modification for those looking to lose weight, and strict adherence improves weight loss. Findings also suggest that there is a need for portion education and estimation assistance for users

Prevalence of Low-Energy Availabilty Amongst Female Paralympic Athletes

The prevalence of low-energy availability (LEA) in able-bodied female athletes has been extensively examined; however, research has yet to examine LEA in Paralympic athletes. Therefore, the purpose of this study was to examine the risk of LEA and related symptoms including menstrual health, hormonal profiles, and bone mineral density (BMD) in female para-athletes. Female national para-athletes (n = 9) completed 7-day food and activity logs, Low Energy Availability in Females Questionnaire (LEAF-Q) and Eating Disorder Examination Questionnaire (EDE-Q), Dual energy X-Ray Absorptiometry (DXA) scans, and hormonal profile blood spot testing. LEAF-Q results suggested that 78% of athletes were considered “at-risk” for LEA, while energy availability calculations based on energy intake (EI) and exercise energy expenditure (EEE) suggested that none of the participants had LEA ( \u3c 30 kcal.kgFFM-1.day-1). Menstrual dysfunction was reported in four participants who were also taking hormonal contraceptives. Hormonal blood spot tests suggested that progesterone was low in 67% of the participants (2.1 + 0.3 nmol/L), with no trends between those considered “at-risk” and “not at-risk” for LEA using LEAF-Q. Triiodothyronine (T3) and estradiol levels were within normal range for all participants. Insulin-growth factor (IGF-1) was elevated ( \u3e 13.1-39.2 nmol/L) in 22% of athletes. Five participants (56%) had clinically low BMD in the hip regional score ( \u3c -2 z-score), one of which reported a bone-related injury within the past year. Based on the LEAF-Q and DXA scans risk of LEA appears to be high;, however, according to the EDE-Q and EA calculation risk of LEA appears to be low. This considerable discrepancy in the assessment tools suggests the need for further investigation using a larger sample size and a wide range of assessment tools to determine which are most effective for assessing energy availability in female para-athletes

The Effect of Fasted vs Fed High-Intensity Interval Exercise on Metabolism and Diet

The purpose of this study was to investigate immediate and delayed metabolic and dietary responses to a single bout of cycling high-intensity interval exercise (HIIE) performed in the fasted and fed state. Baseline values of 11 subjects (6 female, 5 male) for resting energy expenditure (REE), respiratory exchange ratio (RER), resting VO2, VO2max and appetite score (VAS) were measured on the first visit. Energy balance (EB) was determined using diet tracking and activity energy expenditure (paEE). Trials followed a day at net energy balance and began in a fasted state. A 240-kcal energy bar was consumed prior to (FED) or after (FST) a high-intensity interval exercise (HIIE) bout. Post-exercise VO2 was recorded for one hour (60 of 70 minutes) immediately following HIIE. Metabolic variables were measured before and 12 hours after exercise. Energy intake was not different between conditions the day before trials (mean ± SD: 2060 ± 613 kcal FED, 2154 ± 666 kcal FST) or the 12 hours after exercise (1695 ± 484 kcal FED, 1892 ± 822 kcal FST). Post-exercise VAS was greater than 12 hours later (p \u3c 0.01). Post-exercise EE (97.0 ± 15.2 kcal.hr-1 FED, 89.9 ± 17.2 kcal.hr-1 FST) was elevated from pre-exercise (70.8 ± 10.7 kcal.hr-1 FED; p \u3c 0.01, 67.9 ± 10.2 kcal.hr-1 FST; p = 0.01). Post-exercise VO2 (272.2 ± 25.8 mL.hr-1.kg-1 FED, 254.2 ± 33.5 mL.hr-1.kg-1 FST) was elevated from pre-exercise (203.4 ± 25.4 mL.hr-1.kg-1 FED; p \u3c 0.01, 195.6 ± 12.5 mL.hr-1.kg-1 FST; p \u3c 0.01). Excess EE (26.2 ± 10.6 kcal FED, 22.0 ± 11.8 kcal FST) and EPOC (68.8 ± 28.6 mL.kg-1 FED, 58.6 ± 32.5 mL.kg-1 FST) over 60 minutes did not differ between conditions. Appetite was blunted in the hours following HIIE supporting the transient effect of exercise on appetite. Excess EE and EPOC did occur in the hour following exercise. However, whether a 240-kcal meal replacement bar was consumed immediately before or shortly after morning HIIE did not significantly impact resulting EPOC, RER, EI or appetite

The effect of planned exercise as a disinhibitor of dietary restraint : an investigation of perceived control and resultant affect

Recently, Polivy (1992) expressed the need for experimental studies addressing risk factors responsible for unhealthy eating and exercise behaviors. The purpose of the present study was to experimentally manipulate the relationship between exercise and eating behavior to examine if cognitions related to future exercise behavior are associated with caloric indulgence. The psychological set of eaters defined as restrained is theorized to motivate eating when natural physiological hunger cues are controlled, thereby justifying dietary consumption (Herman & Mack, 1975). Therefore, it was of specific interest in this study to examine whether plans for future exercise would lead to increased caloric consumption or "disinhibition" of dietary restraint. In addition, perceptions of control and resultant affect (anxiety and depression) were examined, as these factors have been found to be associated with dysfunctional eating and exercise behavior (Carmack & Martens, 1979; Crossman, et al., 1987; Crowther, et al., 1984; Giles et al., 1985; Gregory, 1981; Hawkins & Clement, 1980; Herman & Polivy, 1975; Morris et al., 1990)

Nutrition Education to Minimize Health Risk: Approaches for Teaching College Students and Female High School Athletes

Adolescence is a time of increased control over food choices and dietary practices. Participating in high school sports or attending college presents unique nutritional concerns and health risks. Some female high school athletes have low energy availability (consuming inadequate calories to compensate for exercise energy expenditure), which can result in menstrual dysfunction, bone loss, and injury, also known as the female athlete triad (Triad). College students who consume diets low in fruits and vegetables and high in fast food are at increased risk for weight gain, chronic disease, and some cancers. Nutrition education interventions that were tailored to the participants\u27 unique nutritional concerns yielded positive results such as increased Triad knowledge among female high school athletes and increased self-efficacy and readiness to change dietary behaviors among college students. Peer-led education was preferred by college students, but not by high school students