Objectifs: Évaluer si un programme d’entraînement en résistance d’une durée d’un an prévient le regain de poids et majore l’amélioration du profil inflammatoire. Le second objectif de cette étude était de déterminer si la variation du tissu adipeux viscéral est associée aux changements dans les concentrations sanguines des marqueurs inflammatoires. Méthodes: Soixante-dix femmes post-ménopausées en surpoids ou obèses ont été randomisées dans un des deux groupes suivants : (1) Contrôle ou (2) Entraînement en résistance. La composition corporelle (absorptiométrie double à rayons X et tomographie axiale) et les marqueurs inflammatoires (protéine C-réactive, orosomucoïde, haptoglobine) ont été évalués avant et après la période de suivi d’une durée d’un an. Résultats: Suite à la période de suivi, un regain significatif de poids corporel et de masse grasse était observé dans le groupe contrôle et le groupe entraînement en résistance (p < 0,05). Une réduction des concentrations sériques de l’orosomucoïde et une hausse des niveaux sériques de l’haptoglobine étaient également notées dans les deux groupes (p < 0,05). La variation du tissu adipeux viscéral était seulement associée aux changements dans les concentrations sériques de la protéine C-réactive (r = 0,373, p < 0,05). Conclusion: Nos résultats suggèrent que l’entraînement en résistance ne prévient pas le regain de poids corporel et ne majore pas l’amélioration du profil inflammatoire chez des femmes post-ménopausées en surpoids ou obèses. De plus, nos résultats indiquent que la variation du tissu adipeux viscéral ne semble pas être un facteur clé impliqué dans les changements des concentrations sanguines des marqueurs inflammatoires. / Objectives: To evaluate if a 1-year resistance training program improved weight loss maintenance and the inflammatory profile in overweight and obese postmenopausal women. The second objective of this study was to determine if the variation in visceral adipose tissue was associated with the changes in inflammatory markers concentrations. Methods: Seventy overweight and obese postmenopausal women were randomized to a control group or a resistance training group. Body composition (dual energy X-ray absorptiometry and computed tomography) and inflammatory markers (C-reactive protein, orosomucoid, haptoglobin) were measured before and after the 1-year weight loss maintenance intervention. Results: Following the weight loss maintenance intervention, we observed a significant body weight and fat mass regain in the control group and the resistance training group (p < 0.05). Significant reductions in orosomucoid and increases in haptoglobin concentrations were noted in both groups (p < 0.05). The variation in visceral adipose tissue was only associated with the changes in C-reactive protein concentrations (r = 0,373, p < 0.05). Conclusion: Our results suggest that resistance training do not improve weight loss maintenance and the inflammatory profile in overweight and obese postmenopausal women. Moreover, our results indicate that the variation in visceral adipose tissue may not be a key factor implicated in the changes in inflammatory markers concentrations.

This thesis investigates the acceptability and efficacy of Functional Imagery Training (FIT), a motivational intervention for weight-management. FIT is based on Elaborated Intrusion Theory, delivered in the style of Motivational interviewing (MI), and designed to promote sustained behaviour change and address cravings. It trains the habitual use of affective, goal-directed mental imagery of personal incentives, using imagery to plan behaviours, anticipate obstacles, and mentally try out solutions from previous successes. Participants are taught to update their imagery from their experience, and to generalise their imagery skills to new goals. In study 1, focus groups explored problems and wishes in regards to weight-management, including reactions to Functional Imagery Training (FIT) as a possible intervention. The issue of waning motivation and the desire for motivational app support was expressed in all groups. Participants were positive about FIT. Study 2 was an uncontrolled pilot trial of FIT. Eleven out of 17 participants (65%) lost 5% body weight or more by three months. Participants continued to lose weight during an unsupported 12-month period and experienced mean weight loss of 6kg (SD= 5.7; d=1.06) and mean waistline reduction of 11.5 cm (SD= 7.4; d=1.56) at 15 months. Study 3 compared the impact of FIT with MI on motivation and self-efficacy, over the first month of a randomised controlled trial (RCT) for weight-loss. Structured elicitation and training in goal-related imagery, i.e., FIT, increased motivation and self-efficacy for weight-loss relative to MI. Study 4 was the RCT for weight-loss, comparing FIT and MI over an intervention-supported six-month period, followed by six months unsupported. The FIT group achieved clinically meaningful weight-loss at 6 months (M kg-loss=4.11) and continued weight-loss at 12 months (M kg-loss=6.44); the MI group stabilised by 12 months (M kg-loss=.67), after minimal weight loss at 6 months (M kg-loss=.74). Study 5 qualitatively explored experiences of MI and FIT RCT participants, upon completing the 6-month intervention phase. MI participants wished for continued therapist- support and feared relapse. FIT participants described a mind-set-change and were confident they could maintain changes and overcome challenges using imagery techniques. Given the demonstrated benefit of motivational imagery in weight-control, FIT should be considered and further tested as an intervention for health behaviour change.

Objectifs: Évaluer si un programme d’entraînement en résistance d’une durée d’un an prévient le regain de poids et majore l’amélioration du profil inflammatoire. Le second objectif de cette étude était de déterminer si la variation du tissu adipeux viscéral est associée aux changements dans les concentrations sanguines des marqueurs inflammatoires. Méthodes: Soixante-dix femmes post-ménopausées en surpoids ou obèses ont été randomisées dans un des deux groupes suivants : (1) Contrôle ou (2) Entraînement en résistance. La composition corporelle (absorptiométrie double à rayons X et tomographie axiale) et les marqueurs inflammatoires (protéine C-réactive, orosomucoïde, haptoglobine) ont été évalués avant et après la période de suivi d’une durée d’un an. Résultats: Suite à la période de suivi, un regain significatif de poids corporel et de masse grasse était observé dans le groupe contrôle et le groupe entraînement en résistance (p < 0,05). Une réduction des concentrations sériques de l’orosomucoïde et une hausse des niveaux sériques de l’haptoglobine étaient également notées dans les deux groupes (p < 0,05). La variation du tissu adipeux viscéral était seulement associée aux changements dans les concentrations sériques de la protéine C-réactive (r = 0,373, p < 0,05). Conclusion: Nos résultats suggèrent que l’entraînement en résistance ne prévient pas le regain de poids corporel et ne majore pas l’amélioration du profil inflammatoire chez des femmes post-ménopausées en surpoids ou obèses. De plus, nos résultats indiquent que la variation du tissu adipeux viscéral ne semble pas être un facteur clé impliqué dans les changements des concentrations sanguines des marqueurs inflammatoires. / Objectives: To evaluate if a 1-year resistance training program improved weight loss maintenance and the inflammatory profile in overweight and obese postmenopausal women. The second objective of this study was to determine if the variation in visceral adipose tissue was associated with the changes in inflammatory markers concentrations. Methods: Seventy overweight and obese postmenopausal women were randomized to a control group or a resistance training group. Body composition (dual energy X-ray absorptiometry and computed tomography) and inflammatory markers (C-reactive protein, orosomucoid, haptoglobin) were measured before and after the 1-year weight loss maintenance intervention. Results: Following the weight loss maintenance intervention, we observed a significant body weight and fat mass regain in the control group and the resistance training group (p < 0.05). Significant reductions in orosomucoid and increases in haptoglobin concentrations were noted in both groups (p < 0.05). The variation in visceral adipose tissue was only associated with the changes in C-reactive protein concentrations (r = 0,373, p < 0.05). Conclusion: Our results suggest that resistance training do not improve weight loss maintenance and the inflammatory profile in overweight and obese postmenopausal women. Moreover, our results indicate that the variation in visceral adipose tissue may not be a key factor implicated in the changes in inflammatory markers concentrations.

Doctor of Philosophy / Department of Family Studies and Human Services / Candyce S. Russell / Despite multiple interventions and the increase of consumer spending on weight management, weight loss maintenance continues to allude most people. This study explores women’s narratives and the ways they made meaning of their weight loss and weight loss maintenance experiences. Examining the processes occurring within the individual and the family context, this study investigated the potential differences between weight loss and weight loss maintenance processes. A grounded theory approach guided the study design, transcription coding, and data analysis. The results revealed four categories (cycles and patterns, fluctuations and thresholds, defining self, and contextual connections) emerging from the research participants’ narratives describing their weight loss and weight loss maintenance experiences. An analytical framework, consisting of the examination of clustered categories using a multifocal lens and a toggling procedure, facilitated the development of multidimensional descriptions of the women’s experiences and guided the process of analysis. The process of analysis was isomorphic to the process the women used to formulate their narratives. The women incorporated multiple dimensions of their experiences to create narratives that described and informed their weight loss and weight loss maintenance efforts. The analysis also revealed that weight loss and weight loss maintenance are multi-dimensional processes. The dimensions reflect both similarities and differences between the processes. Some women used heroic while others used integrative efforts to lose weight. Their efforts impacted the amount of overlap they experienced between the weight loss and weight loss maintenance processes. Implications for further studies are presented for using the analytical framework to understand the meaning-making processes occurring with weight loss and weight loss maintenance. Potential clinical implications for addressing weight loss and weight loss maintenance within family and relational contexts are explained.

Weight loss maintenance is essential for the reduction of obesity-related health impairments. However, only a minority of individuals successfully maintain reduced weight in the long term. Research has provided initial evidence for associations between weight-related teasing (WRT) and greater non-normative eating behaviors. Further, first evidence was found for associations between non-normative eating behaviors and weight loss maintenance. Hence, the present study aimed to examine the predictive value of WRT for weight loss maintenance and the role of non-normative eating behaviors as possible mediators of this relationship. The study was part of the German Weight Control Registry that prospectively followed individuals who had intentionally lost at least 10% of their maximum weight and had maintained this reduced weight for at least one year. In N = 381 participants, retrospective WRT during childhood and adolescence, current non-normative eating behaviors (i.e., restrained, external, emotional eating), and change in body mass index (BMI, kg/m2) over two years were examined using self-report assessments. Structural equation modeling was used to analyze the assumed mediational relationship. As a result, a greater effect of retrospective WRT during childhood and adolescence predicted less successful adult weight loss maintenance over two years. Current emotional eating fully mediated this relationship while current restrained and external eating yielded no mediational effects. Hence, a greater effect of WRT predicted greater current emotional eating, which in turn predicted a smaller decrease or a greater increase in BMI. Our findings suggest that suffering from WRT during childhood and adolescence might lead to emotional eating which in turn impairs long-term weight loss maintenance. Thus, our results highlight the need for interventions aiming at reducing weight stigmatization and targeting emotional eating for successful long-term weight loss maintenance.

Contexte / Objectif: Le maintien de la perte de poids est essentiel pour la gestion de l'obésité et des maladies chroniques associées. Cette étude vise à identifier les stratégies et les barrières associées à la perte de poids à long terme chez les femmes en surpoids et obèses au Québec. Méthode: Une étude transversale utilisant un modèle de triangulation simultanée entre les méthodes quantitatives et qualitatives a été utilisée. Pour colliger les données quantitatives et qualitatives, un questionnaire a été administré aux participantes par téléphone par la chercheuse de l’étude et une série de questions ont été envoyées par courriel afin de compléter l’analyse qualitative. Un total de 29 femmes en surpoids ou obèses ayant suivi une intervention de perte de poids avec la diététiste (également la chercheuse de cette étude) ont été incluses. Une perte de poids de 5% maintenue pendant au moins un an a été considérée comme un maintien de perte de poids réussi (n = 15). Sinon, elles étaient classées comme une non-réussite (n = 14) du maintien de la perte de poids. Résultats: Les participantes ayant maintenues leur poids avaient plus de probabilités d’avoir complété un niveau de scolarité plus élevé et d’avoir perdu plus de poids après le premier mois d’intervention nutritionnelle que les participantes qui avaient repris leur poids. Les stratégies individuelles significativement plus utilisées chez les réussites du maintien de perte de poids comparé aux non-réussites étaient; augmenter la consommation d'aliments non transformés ou peu transformés, limiter la consommation d'aliments ultra-transformés, réduire la taille des portions et faire de l’activité physique (AP) (≥ 40 minutes / jour). Les stratégies environnementales telles que; avoir le soutien d’un réseau social et créer un environnement alimentaire plus sain à la maison étaient légèrement plus rapportées par les réussites de perte de poids. La barrière principale au maintien de la perte de poids était la tentation des aliments pour les personnes qui avaient maintenues leur poids, tandis que pour les participantes classées comme «non-réussite», la pratique de l'AP était leur principale barrière. Conclusion: Le succès de la perte de poids est complexe, multifactorielle et dépend du contexte. Il n'y a pas de «stratégie unique» pour le succès du maintien de la perte de poids. Une perte de poids à long terme est possible, mais elle nécessite de suivre des principes de bases telles que de limiter la consommation d’aliments ultra-transformés, augmenter la consommation d’aliments non ou minimalement transformés, cuisiner et réduire les portions, et ces principes doivent être durables. Pour augmenter les chances de réussite du maintien de la perte de poids, les individus et les professionnels de la santé devraient cibler des stratégies en fonction de la compréhension de l’interaction entre les choix individuels et plusieurs dimensions de l’environnement alimentaire qui les déterminent, ainsi que du contexte particulier dans lequel les individus évoluent. / Background/Objective: Weight loss maintenance is crucial for successful management of obesity and its related chronic disease. This study aimed to identify strategies and barriers associated with long-term weight loss among overweight and obese women in Quebec. Method: This study employed a cross-sectional method using a concurrent triangulation design that uses quantitative and qualitative instruments. To collect the quantitative and qualitative data, a questionnaire was administered to participants over the phone by the researcher and another series of questions were sent by email to participants to complete the qualitative analysis. A total sample of 29 overweight or obese women who had previously completed a weight loss intervention program with a registered dietitian (who is also the researcher of this study) were included. A 5% weight loss maintained for at least one year was considered a successful weight loss maintenance (n=15) and these participants were classified as maintainers. Otherwise, participants were classified as re-gainers (n=14). Results: Maintainers were more likely to have completed a higher level of education and to have lost more weight after the first month of nutrition intervention when compared to regainers. Individual strategies used significantly more within maintainers when compared to regainers included: increasing unprocessed or minimally processed food consumption, limiting ultra-processed food consumption, reducing portion sizes, and practicing physical activity (PA) (≥40 minutes/day). Social and environmental strategies such as having a supportive network and creating a healthy food environment at home were reported more by maintainers. The main barrier to weight loss maintenance was food temptation for maintainers whereas practicing PA was the main barrier for re-gainers. Conclusion: Weight loss success is complex, multifactorial, and context dependent. There is no “one size fits all strategy” for successful weight loss maintenance. Long-term weight loss is possible but requires following basic principles such as limiting ultra-processed foods, increasing whole and minimally processed food, cooking more and reducing portions, and these principles must be sustainable. To increase chances of successful weight loss maintenance, individuals and health professionals should target strategies according to an understanding of the interaction between individual choices and several dimensions of the food environment influencing these choices.

Text in English / In order to address the paucity of knowledge in regard to the psychological and physiological processes associated with lifelong weight loss (>20 years), this study adopts a qualitative approach informed by phenomenology to explore the experience of lifelong weight loss and maintenance of women who participated in the ITAND Programme. The research questions guiding the exploration of the current research are: (i) Which strategies from the ITAND Programme do women perceive as assisting with initial weight loss? (ii) What are the processes mediating lifelong weight loss? (iii) What strategies and skills mediate the maintenance of lifelong weight loss? (iv) What feelings or beliefs motivate women to continue attempts to lose weight after experiencing multiple failures on diets? and (v) Which psychological, cognitive and behavioural processes are identified as mediating lifelong weight loss? Eight overweight and obese women were invited to write their narratives and engage in interviews in regard to exploring their relationships with food, their bodies and their weight, after a period of more than 20 years following their participation in an integrative, transactional analysis, anti-diet programme (the ITAND Programme). Narratives were used to explore their beliefs about constructs, processes and strategies mediating long-term weight loss maintenance. The participants’ narratives and interviews were analysed through applying narrative analysis and interpretive phenomenological analysis. In addition to a non-diet paradigm, four processes definingweight loss maintenance were identified, including the adult learning process of transformative learning, the psychological process of transactional analysis, the physiological process of intuitive eating and the cognitive-behavioural processes relating to weight loss maintenance. This study contributes an integrative, transactional analysis, non-diet treatment model (ITAND model) which is enabled by the processes of transformative learning, intuitive eating and cognitive-behaviour modification to the successful long- term treatment of overweight and obesity. This model may be applied in whole or in part in a primary health care or community context. The findings of this study may be used to inform future research into the development and implementation of non-diet weight loss maintenance interventions in the treatment of overweight andobesity. / Psychology / D.Litt. et Phil. (Psychology)

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