Thesis (M.A. (Human Movement Science))--North-West University, Potchefstroom Campus, 2009.

BACKGROUND: Diaclyglycerol (DAG) oil has the potential as an effective weight control agent as well as an agent to modify overweight related complications. OBJECTIVE: We aim to examine the efficacy of DAG oil (Enova oilTM) on regulating energy expenditure (EE), fat oxidation, body composition, lipid profiles and hepatic lipogenesis in comparison with conventional oils. DESIGN: Twenty-six overweight hypertriglyceridemic women consumed DAG or control oil for 28 days separated by a 4-week washout period using a randomized crossover design. Forty grams of either DAG or control oil were consumed daily by each study subject. RESULTS: DAG oil consumption for a period of 4-week does not alter total EE, fat oxidation, lean mass, fasting lipid profile or fatty acids synthesis rate, but effectively reduces (p<0.05) body weight and adiposity. CONCLUSION: DAG oil maybe an useful agent in the battle against obesity. However, its body weight/composition control effects are not from increasing of lean mass, or postprandial EE and fat oxidation. The consumption of DAG oil for a period of 4-week does not necessarily modify fasting lipid profiles or hepatic lipogenesis to reduce risk of coronary heart diseases in overweight hypertriglyceridemic subjects.

Thesis (M.A. (Human Movement Science))--North-West University, Potchefstroom Campus, 2009.

Children are becoming more inactive and are spending a significant proportion of their time participating in screen-time sedentary behaviours. New generation active video games may provide an opportunity to convert traditional sedentary screen-time into active screen-time. The aims of this thesis were to: 1) determine the metabolic costs of different activities; 2) determine whether experience and fitness influence the metabolic costs of active video games; and 3) determine children's enjoyment of active video games. Accordingly, this thesis is presented as two papers. Twenty-six boys' (11.4 ± 0.8 yr) participated in the study. Each performed sedentary activities (resting, watching television and sedentary gaming), active video games (Nintendo® Wii Bowling, Boxing, Tennis, Skiing and Step Aerobics), traditional physical activities (walking and running) and a maximal fitness test. During all activities oxygen uptake and heart rate were measured and energy expenditure (EE) calculated. The active video games resulted in a significantly higher EE compared to rest (63-190%, p<0.05). No significant differences in EE were found between the most active video games (Wii Boxing and Wii Step) and walking. The intensities of the active video games were low (≤ 3 METSmeas). There was no evidence to suggest that gaming experience or aerobic fitness influenced EE during active video game play. Using the same sample, the aim was to determine the participants' enjoyment of active video games sedentary activities and physical activities. Participants' enjoyment was measured using the Physical Activity Enjoyment Scale immediately after the activities. The percentages of children that enjoyed each activity were: walking (39%), television (58%), running (60%), PS3 (73%), Wii Boxing (88%), Wii Tennis (77%), Wii Fit (75%) and Wii Bowling (89%). The active video games were the most enjoyable activities irrespective of participants' weight status, fitness and experience. The metabolic costs of active video games suggest that they may be suitable for future interventions which are aimed at decreasing time spent in sedentary behaviour. However, as they are low intensity activities, active video game play time should not be accumulated as part of the 60-minutes of daily moderate to vigorous physical activity that is currently recommended for children.

A number of strategies to lose weight are available. However, a high inter-individual variability is commonly observed in terms of weight loss and its maintenance in individuals enrolled in different interventions. This high variability is mainly explained by individual differences in the activation of compensatory mechanisms triggered by energy deficits. Increases in appetite ratings as well as the rewarding effects of foods are some of the consequences commonly observed from weight loss induced by caloric restriction. On the other side of the energy balance equation, resting energy expenditure (REE) was also found to decrease as consequence of weight loss. Numbers might in fact decrease beyond what could be expected from changes in body weight and composition, highlighting an adaptation in thermogenesis in some individuals. These changes were previously found to be associated with the magnitude of weight loss. However, it is not clear whether different rates of weight loss have a different impact on the compensatory mechanisms described above. Moreover, other questions regarding weight loss maintenance deserve further investigations. For example, the role of exercise, more specifically resistance training (RT), on weight loss maintenance needs additional attention. Accordingly, the present thesis aimed to investigate the effects of caloric restriction on compensatory mechanisms that occur during and after weight loss. We first aimed to determine whether the rate of weight loss differently influence physiological and psychological variables related to energy balance. Secondly, we aimed to elucidate whether early changes in the above mentioned adaptations in energy expenditure (EE) and energy intake (EI) variables predict final outcomes (fat mass - FM and weight loss). Finally, we aimed to determine whether RT promoted greater weight loss maintenance. In Article I and II, we investigated whether different rates of weight loss play a role in EI and EE related-variables. We noted significant increases in fasting appetite measures, as well as increases in satiety measures. REE decreased over time, as did the relative reinforcing value of fruit. No significant group interaction was observed illustrating that different rates of weight loss has no impact on the magnitude of adaptations in EI and EE after weight loss. In article III we demonstrated that early changes in fasting and postprandial appetite measures in response to caloric restriction were associated with greater body weight and FM loss in women. Indeed, greater increases in fasting appetite were associated with greater FM loss, contrary to our hypothesis. However, increases in postprandial appetite were associated with greater FM and body weight loss, independently of changes in eating behaviours. Taken together, articles I and III demonstrated that caloric restriction has a significant impact on increases in appetite and reduction in REE as soon as the in the first week of intervention. Those changes remain significant until the end of the program. In article IV it was shown that 1-year of resistance training (2x/ week) after 6-month of caloric restriction was not sufficient to promote better weight and FM loss in post-menopausal women. Furthermore, the results demonstrated that RT did not improve the differences between measured and predicted measures in REE observed as consequence of weight loss. The picture that emerges is that, increases in appetite and decreases in REE can be observed since the first week of caloric restriction and remain significant until the end of the program, independently of the rate of weight loss. Feeding-related variables such as fasting and postprandial appetite and RRV of a snack food are better predictors of final FM loss, even after adjusting for changes in eating behaviours. In addition, our study demonstrated that different rates of weight loss do not have an independent aspect on either physiological or psychological aspects related to energy balance.

In this study, examinations of 6 patiens of the ICU of the University Hospital in Hradec Kralove were included. The aim of this study was to describe case reports of individual patients and to look for statistically significant correlations between nutritional support, oxidation of nutrients and other parameteres. Anthropometric measuring and indirect calorimetry were used for the examination of patients. The case reports show the individuality that occurs in patients. Spearman's correlation analysis was used to evaluate measured data. Statistically significant correlations were proven, among them relations between enterally given nutrition and the creation/loss of muscle tissue (carbohydrates: P = 0,000189, lipids: P = 0,001284, proteins: P = 0,000255), between carbohydrate oxidation, resp. protein oxidation and the number of hours spent on ventilation (carbohydrates: P = 0,041278, proteins: P = 0,02185), between respiratory quotients and the duration of the trauma (respiratory quotient: P = 0,014695, nonprotein respiratory quotient: P = 0,027904), between carbohydrate oxidation related to ideal body weight and lipid intake (P = 0,014085) and between protein oxidation and carbohydrate intake (P = 0,012703). Key words: polytrauma, indirect calorimetry, nutritional support, malnutrition

Active video games (AVG) have been shown to acutely increase energy expenditure when compared to seated video games; however, the compensatory effects on energy intake and subsequent energy expenditure are largely unknown. The main objective of this thesis was to examine the acute effects of AVG on energy intake and expenditure in male adolescents. Our results suggest that male adolescents compensate for one hour of AVG play by decreasing their physical activity levels for the remainder of the day. There was no compensation in acute energy intake with AVG play. The results from this thesis suggest that the benefits of one hour of Kinect™ AVG play are offset within 24 hours in male adolescents. Therefore, caution must be exercised when prescribing AVG for interventions aimed at preventing/treating childhood obesity.

Les études à long-terme confirment que la combinaison d’un déficit calorique et d’un programme d’exercice est une intervention plus profitable quant à la perte de poids qu’un régime hypocalorique ou un programme d’exercice seul. Toutefois, la perte de poids moyenne de l’approche combinée est en générale inférieure à celle estimée sur la base du déficit calorique et de la dépense énergétique du programme d’exercice. L’objectif principal de cette étude portait sur l’investigation des effets d’un déficit calorique et de l’exercice sur l’apport calorique, la dépense énergétique totale, la thermogenèse d’origine autre que l’exercice et la compensation alimentaire post-exercice chez les jeunes femmes. Huit jeunes femmes de poids normal et inactives ont participé à quatre conditions expérimentales : contrôle; exercice, où une séance d’exercice à intensité modérée a été réalisée; déficit calorique, où un déficit calorique de 25% pour une période de 3 jours consécutifs a été respecté; et exercice/déficit calorique. À la suite de chaque session, un repas ad libitum à l’heure du dîner a été offert aux participantes et des boîtes à lunch contenant des aliments à volonté choisis par l’entremise de menu ont été remises à ces dernières pour couvrir l’apport calorique pour la journée (jour 1) ainsi que la journée subséquente (jour 2). De plus, un accéléromètre a été remis à chaque participante après chaque séance expérimentale pour être en mesure d’estimer la dépense énergétique liée à l’activité physique pour le jour 1 et jour 2. Aucune différence significative n’a été observée entre les différentes conditions expérimentales pour l’apport calorique au repas ad libitum post-exercice, au jour 1 ainsi qu’au jour 2. De plus, aucune différence significative n’a été notée pour la dépense énergétique totale ainsi que la thermogenèse d’origine autre que l’exercice et aucune compensation alimentaire post-exercice n’a été observée en fonction des conditions expérimentales. Ces résultats suggèrent que la combinaison d’un déficit calorique de 3 journées consécutives avant une séance d’exercice d’intensité modérée n’influence pas l’apport calorique post-exercice, la dépense énergétique totale, la thermogenèse d’origine autre que l’exercice et n’engendre pas de compensation alimentaire post-exercice. Un déficit calorique combiné à l’exercice d’une période plus prolongée pourrait être nécessaire afin d’observer une augmentation de la compensation alimentaire post-exercice pendant une intervention qui vise à induire une perte de poids.

This thesis aims to determine energy compensation following exercise induced energy expenditure (ExEE). The specific objectives were: I) to determine the impact of the time spent performing physical activity (PA) of varying intensities on body weight and composition (Study 1); II) to determine the overall energy compensation and the major predictors of energy compensation through the systematic review approach (Study 2); III) to develop new methods to measure energy intake (EI) (Study 3) and time spent performing different activities (Study 4); IV) to determine the effects of a lower (LI) and higher intensity (HI) ExEE intervention on energy compensation (Study 5); and V) to investigate the inter-individual variability regarding exercise induced energy compensation (Study 6). In Study 1, women spending more time performing light-intensity PA were shown to have lower adiposity compared to women spending more time performing moderate- and high-intensity PA. Results from Study 2 (systematic review) show an overall energy compensation of 25% following exercise interventions and that fat mass (FM), exercise intensity and duration of the intervention are the main predictors of energy compensation. To better capture energy compensation (i.e., EI and EE), new methods to measure EI and time spent performing activities were developed (Studies 3 and 4) and used in the following studies. In Study 5, overweight/obese women training at HI displayed higher energy compensation when compared to women training at LI, which was accompanied by a reduction of NSPA (non-structured physical activity) and a greater amount of time spent lying down. Results from Study 6 showed that complete compensators (CC) had higher EI, fat and carbohydrate intake at the onset of the ExEE intervention when compared to incomplete compensators (IC). However, the results also showed that dietary disinhibition was increased, whereas NSPA was decreased at the end of the intervention in IC. Taken together, these studies emphasize that weight loss following exercise is impeded by energy compensation. In addition to the impact of FM, exercise intensity and duration of the intervention on energy compensation, NSPA and cognitive factors also seem to modify energy compensation that occurs as a result of exercise.

Watching television or listening to music during exercise has been shown to increase the enjoyment of the activity and decrease fatigue for some people. However, it is currently unknown how these stimuli during an exercise session play a role in postexercise energy intake and/or physical activity energy expenditure (PAEE). The purpose of this thesis was to examine the effects of watching television or listening to music while exercising on post-exercise energy intake and expenditure in male adolescents. The study consisted of a randomized crossover design involving 24 male adolescents aged 12 to 17 years. The participants completed three experimental sessions that included walking/jogging on a treadmill at 60% of their heart rate reserve for 30 minutes while watching television, listening to music, or exercising with no other stimulus (control). Following the exercise sessions participants were given an ad libitum lunch and were asked to record their food intake for the remainder of the day. An Actical accelerometer was used to assess PAEE until bedtime. The primary outcome measure was post-exercise energy intake and energy expenditure. Results showed that exercising while watching television or listening to music did not significantly affect postexercise energy intake or energy expenditure. Walking/jogging on a treadmill was found to be more enjoyable while watching television than with no stimulus present (p=0.03). Ratings of perceived exertion were not significantly different between conditions. Overall, our results suggest that watching television or listening to music while exercising does not impact post-exercise energy intake or expenditure in male adolescents, which may have positive implications for adolescents who may need additional motivation to exercise.