To examine the acute effects of exercise timing and meal glycemic index (GI) on fat oxidation and glycemic response, five apparently healthy young men participated in four randomly ordered morning trials during which measurements were made at rest, during exercise, and for two hours post-exercise. A factorial design [exercise timing (pre-prandial, post-prandial) x meal GI (low-GI, high-GI)] was used for repeated measures of energy expenditure and whole-body fat oxidation, as well as of plasma glucose and insulin levels after an overnight fast. Subjects were required to perform 400 kcal of moderate treadmill exercise either before consuming a 400 kcal low-GI (ELG) or high-GI (EHG) oatmeal breakfast, or after consuming the low-GI (LGE) or high-GI (HGE) meal. Exercising fat oxidation was significantly greater during ELG and EHG (14.7 +/- 1.4 and 14.8 +/- 3.2g, respectively) than during LGE and HGE (8.9 +/- 3.1 and 9.8 +/- 2.7g, respectively) (p < .001), as was total fat oxidation beyond rest and (ELG: 21.3 +/- 3.7g; EHG: 20.2 +/- 5.9g; LGE: 18.1 +/- 6.0g; HGE: 17.1 +/- 3.4g) (p < .05), although energy expenditure was unaffected by experimental conditions. No significant effect of meal GI on fat oxidation was observed and, unexpectedly, the glycemic response was not significantly different across experimental conditions. Total whole-body fat oxidation for the entire morning period is therefore greatest when exercise is performed in the post-absorptive state, a strategy that could help maximize acute exercise-induced fat oxidation.

The high incidence of obesity and obesity related diseases have been well-documented within First Nations communities across Canada. Therefore, examining current dietary choices and then altering and managing alternative healthier choices are essential in the treatment of obesity and its related diseases. The present article describes a dietary study looking specifically at the dietary choices of women living in a First Nation's community in northwestern Ontario. An ethnography was conducted over a three-week period in which the researcher attended community events and interviewed twenty six women. Experiences in women's lives led them on different life courses. Family involvement and age of women influenced transmission of informal knowledge and feelings of self worth. These and other factors influenced the life course and the resultant "dietary trajectory" from which women made choice. Considering individuals in changing social, cultural and historical climates deemed the life course perspective applicable in this study. Findings suggest that solutions to the "health epidemic" can be found by looking to the women in the community who are making nutritious choices. From this point, formal and informal programs that facilitate reintroduction of traditional knowledge into lives of younger community members can be developed.

L'objectif principal de cette these etait de caracteriser l'impact d'une consommation alimentaire quotidienne reduite en calorie ou enrichie de gras polyinsatures (PUFA) sur les repercussions neuronales et fonctionnelles d'une ischemie cerebrale globale. Differents groupes de rats furent assignes aleatoirement aux conditions experimentales, determinees par la diete consommee et la procedure chirurgicale administree. Les regimes alimentaires des deux premieres etudes de cette these incluaient l'ingestion alimentaire ad libitum ou une restriction alimentaire de 40% comparee a l'ingestion des rats des groupes ad libitum. Dans une troisieme etude, nous avons evalue l'impact de la consommation d'une diete enrichie de gras polyinsatures de type omega 3 et omega 6, via l'ajout de 11.5% d'huile de poisson et de 3.5% d'huile de mais a la diete controle. Ces differentes dietes furent toutes initiees chez des rats ages de 4 semaines et maintenues pendant une periode de 18 semaines (pre et post-chirurgie). Les procedures chirurgicales, administrees durant la 13ieme semaine d'ingestion alimentaire, incluaient soit une chirurgie vasculaire impliquant 8 ou 12 minutes d'ischemie cerebrale globale ou une operation controle (chirurgie sham). Suite a ces procedures, l'administration d'une serie de paradigmes comportementaux debuta pour l'ensemble des animaux au 4ieme ou 5ieme jour suivant la chirurgie, et se terminant 7, 31 ou 70 jours suivant l'ischemie, dependamment de l'experimentation. Les tests comportementaux utilises incluaient l'aire ouverte, le labyrinthe en croix et le labyrinthe radial a huit bras. A l'instar des recherches suggerant des effets neuroprotecteurs de la restriction alimentaire et de l'ingestion de supplements d'acides gras polyinsatures, nos resultats demontrent que la survie neuronale dans le CA1 de l'hippocampe est comparable entre les rats ischemies nourris des dietes experimentales et ceux nourris a volonte. Cette absence de difference s'observe 7, 31 et 70 jours suivant la procedure chirurgicale. Egalement, nos resultats comportementaux revelent une reduction significative, voire la prevention, des deficits d'apprentissage et de memoire spatiale induits par l'ischemie globale chez les rats restreints et nourris d'une diete enrichie de PUFA. Les performances mnesiques de ces animaux sont comparables a celle des rats controles et significativement meilleure que celle des rats ischemies nourris d'une diete reguliere. Fait plus impressionnant, les animaux ischemies restreints demontrent egalement la capacite de completer une serie de taches differees complexes appariees ou non a l'echantillon (DMTS/DNMTS) dans le labyrinthe radial, contrairement aux rats ischemies nourris a volonte. Nos resultats suggerent que la restriction alimentaire et l'ingestion de supplements d'acides gras polyinsatures induisent des changements plastiques et/ou l'activation de mecanismes endogenes compensatoires capables de proteger les animaux des deficits d'apprentissage et de memoire spatiale generalement produits par l'ischemie globale.

As the efficacy of clinical management of HIV infection continues to improve, there is a growing need for outcomes research to focus on finding ways to improve physical well-being and quality of life. Weight loss and body cell mass (BCM) depletion are two clinical issues that have received ongoing attention from researchers, given that both are potent predictors of morbidity in HIV-infected individuals. In this series of studies, three primary issues were addressed. First, the relationship between pharmacological (oxandrolone) and nutritional therapies and changes in BCM and body weight was examined over a 4-mo descriptive clinical trial. Second, the impact of these changes was considered in terms of quality of life change. Third, these analyses provided an opportunity to compare single-frequency bioelectrical impedance with multi-frequency bioelectrical impedance methods for measuring BCM change. There were a number of compelling findings in this research. First, HIV-infected individuals receiving oxandrolone and nutritional intervention were observed to gain both body weight and BCM. Significant relationships were observed between weight gain and improved quality of life, physical well-being, and appetite. In addition to these results, the use of bioimpedance spectroscopy (BIS) was demonstrated to have several advantages over the more commonly used single-frequency bioelectrical impedance method for measuring BCM in the field, including the ability to provide valid measures of BCM in HIV infection. Based on these findings, it appears that early identification by a valid field method, BIS, and a multi-faceted therapeutic approach may be most effective in the treatment of weight loss and BCM depletion in HIV-infected individuals.

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