This thesis is an analysis of how societal values shape our ideas of health and disease, the designs and marketing of weight loss surgery technologies, and the ways in which obesity reducing-operations are accepted and desired. Gender ideologies, American values of commodity capitalism, treatment that focuses on the individual, and a moral aversion to fat have all shaped the medical treatment of obesity as an epidemic and the promotion of weight loss surgery as the best available solution. In this project, I approach the question of obesity by deconstructing the terms that have framed it as a social problem and I show how and why specific technological remedies have been pursued. My thesis is that among obese Americans, females and their bodies are especially stigmatized and pathologized. Because of this, efforts and applications of science, technology, medicine, and policy focus to "fix" these bodies/people, which are considered out of control. / Master of Science

The purpose of this study was to explore whether overweight college dieters, engaged in self-structured weight loss efforts, experienced physical symptomatology that has previously been associated with severe caloric restriction. The relationships between physical symptomatology, self-efficacy, and future dieting behavior were also investigated. Forty college students (21 female, Mage = 19.58 years, SD= 1.85) self-reported caloric intake and completed self-efficacy measures and physical symptom reports for three weeks. Results indicated that weekly physical symptom reports were not associated with caloric deficit and did not predict future dieting behavior. Physical symptoms were negatively related to self-efficacy for dieting and exercise as predicted, but in several analyses, higher self-efficacy actually predicted less calorie restriction. Physical symptom reports were predicted by trait neuroticism and neuroticism was also significantly and negatively associated with eating and exercise self-efficacy. Results raised issues about the accuracy of caloric restriction reporting and suggested that personality characteristics may have an important impact on an individual's perception of dieting experiences and levels of self-efficacy during dieting. / Master of Science

Yes / Obesity is a global public health concern. Interventions rely predominantly on managing dietary intake and increasing physical activity; however, sustained adherence to behavioral regimens is often poor. The lack of sustained motivation, self-efficacy, and poor adherence to behavioral regimens are recognized barriers to successful weight loss. Avatar-based interventions achieve better patient outcomes in the management of chronic conditions by promoting more active engagement. Virtual representations of self can affect real-world behavior, acting as a catalyst for sustained weight loss behavior. We evaluated whether a personalized avatar, offered as an adjunct to an established weight loss program, can increase participant motivation, sustain engagement, optimize service delivery, and improve participant health outcomes. A feasibility randomized design was used to determine the case for future development and evaluation of avatar-based technology in a randomized controlled trial. Participants were recruited from general practitioner referrals to a 12-week National Health Service weight improvement program. The main outcome measure was weight loss. Secondary outcome measures were quality-of-life and self-efficacy. Quantitative data were subjected to descriptive statistical tests and exploratory comparison between intervention and control arms. Feasibility and acceptability were assessed through interviews and analyzed using framework approach. Health Research Authority ethics approval was granted. Overall, 10 men (n=7, 70% for routine care and avatar and n=3, 30% for routine care) and 33 women (n=23, 70% for intervention and n=10, 30% for routine care) were recruited. Participants' initial mean weight was greater in the intervention arm than in the routine care arm (126.3 kg vs 122.9 kg); pattern of weight loss was similar across both arms of the study in T0 to T1 period but accelerated in T1 to T2 period for intervention participants, suggesting that access to the self-resembling avatar may promote greater engagement with weight loss initiatives in the short-to-medium term. Mean change in participants' weight from T0 to T2 was 4.5 kg (95% CI 2.7-6.3) in the routine care arm and 5.3 kg (95% CI 3.9-6.8) in the intervention arm. Quality-of-life and self-efficacy measures demonstrated greater improvement in the intervention arm at both T1 (105.5 for routine care arm and 99.7 for intervention arm) and T2 (100.1 for routine care arm and 81.2 for intervention arm). Overall, 13 participants (n=11, 85% women and n=2, 15% men) and two health care professionals were interviewed about their experience of using the avatar program. Participants found using the personalized avatar acceptable, and feedback reiterated that seeing a future self helped to reinforce motivation to change behavior. This feasibility study demonstrated that avatar-based technology may successfully promote engagement and motivation in weight loss programs, enabling participants to achieve greater weight loss gains and build self-confidence. ISRCTN Registry 17953876; https://doi.org/10.1186/ISRCTN17953876. / This study was funded by the National Institute for Health Research (Research for Patient Benefit program [project reference PB-PG-1215-20016]).

A strategy for facilitating post-treatment weight maintenance was examined. Subjects were matched for age, sex, and amount of weight that they desired to lose and were then assigned to one of two groups. Both groups were under contracts and had individually designed self-control programs for weight loss, but subjects in the experimental group lost weight in small steps and subjects in the control group lost weight continuously. The experimental group was predicted to have better weight maintenance after treatment because of a greater number of reinforcements for weight loss. Two-month follow-up data was obtained on the ten subjects who completed the study, and the experimental group was found to have regained significantly less than the control group after treatment ended. The implications of these results for obesity research are discussed.

Doctor of Philosophy (PhD) / Introduction: The conventional approach to weight loss, recommended by almost all health authorities around the world, has been to reduce the total amount of fat in the diet and replace with carbohydrates. However, research trials using this approach have produced only modest results at best, and despite the active promotion of low fat eating and an apparent decline in fat consumption, rates of overweight and obesity have continued to climb. More recently low glycaemic index (GI) and high protein diets have become popular and are widely used by the public. However, only a small number of randomised controlled trials have been conducted and none directly comparing the two. Both approaches effectively reduce glycaemic load (GL) and aim to reduce post-prandial glycaemia and insulinaemia. This study aimed to evaluate the ability of diets with reduced GL to enhance the weight loss effects of a reduced-fat diet, to compare the two approaches of reducing GL on metabolic and anthropometric changes, and to investigate any benefit of combining both approaches to produce the lowest GL. Methods: We conducted a 12-week intervention in 129 overweight or obese young adults who were assigned to one of four diets with varying GL, protein, carbohydrate and GI, but similar fat (30% energy), fat type and fibre content. DIET 1 (highest GL) contained 55% E as carbohydrate; DIET 2 was a low-GI version of DIET 1; DIET 3 was a high protein diet with 25% E as protein; DIET 4 (lowest GL) was a low-GI version of DIET 3. The increase in protein in DIETS 3 and 4 came primarily from lean red meat. All key foods and some pre-prepared frozen meals were provided to maximise dietary compliance. Outcome measures were body weight, body fat, lean mass, waist circumference and the following blood parameters: total cholesterol, LDL-cholesterol, HDL-cholesterol, triacylglycerols (TAG), free fatty acids, C-reactive protein, fasting insulin, fasting glucose and leptin. Insulin resistance and β-cell function were assessed using homeostatic model assessment (HOMA) and the newer computer models HOMA2-insulin sensitivity and HOMA2-β-cell function. Results: While all groups lost similar amounts of weight (4.2 to 6.2% of initial weight, p=0.09), the proportion who lost >5% of body weight varied significantly by diet: 31%, 56%, 66% and 33% in groups 1, 2, 3 and 4 respectively (p=0.011). Differences were strongest in women (76% of the total group) who showed significant differences among groups in percentage weight change (-3.7 ± 0.6%, -5.7 ± 0.6%, -6.5 ± 0.5%, -4.1 ± 0.7% respectively, p=0.005) and fat loss (-3.1 ± 0.4kg, -4.9 ± 0.6kg, -4.8 ± 0.4kg, -3.6 ± 0.7kg respectively, p=0.007). Total and LDL-cholesterol increased on DIET 3 (high protein) compared to a fall on diet 2 (high carbohydrate/low-GI, p=0.013). TAG, HDL-cholesterol and glucose homeostasis improved on all four diets, with no effect of diet composition. Goals for energy distribution were not achieved exactly: both carbohydrate groups ate less fat and the diet 2 group ate more fibre. Conclusions: Reducing GL, through either substituting low-GI foods or replacing some carbohydrate with protein, improved the efficacy of a reduced-fat diet in women and in those with high TAG. Combining both approaches to produce the lowest GL did not promote further weight or body fat loss. Although weight loss was similar in all four diets for the group as a whole, overall clinical outcomes were superior on the high carbohydrate, low-GI diet.

Doctor of Philosophy (PhD) / Introduction: The conventional approach to weight loss, recommended by almost all health authorities around the world, has been to reduce the total amount of fat in the diet and replace with carbohydrates. However, research trials using this approach have produced only modest results at best, and despite the active promotion of low fat eating and an apparent decline in fat consumption, rates of overweight and obesity have continued to climb. More recently low glycaemic index (GI) and high protein diets have become popular and are widely used by the public. However, only a small number of randomised controlled trials have been conducted and none directly comparing the two. Both approaches effectively reduce glycaemic load (GL) and aim to reduce post-prandial glycaemia and insulinaemia. This study aimed to evaluate the ability of diets with reduced GL to enhance the weight loss effects of a reduced-fat diet, to compare the two approaches of reducing GL on metabolic and anthropometric changes, and to investigate any benefit of combining both approaches to produce the lowest GL. Methods: We conducted a 12-week intervention in 129 overweight or obese young adults who were assigned to one of four diets with varying GL, protein, carbohydrate and GI, but similar fat (30% energy), fat type and fibre content. DIET 1 (highest GL) contained 55% E as carbohydrate; DIET 2 was a low-GI version of DIET 1; DIET 3 was a high protein diet with 25% E as protein; DIET 4 (lowest GL) was a low-GI version of DIET 3. The increase in protein in DIETS 3 and 4 came primarily from lean red meat. All key foods and some pre-prepared frozen meals were provided to maximise dietary compliance. Outcome measures were body weight, body fat, lean mass, waist circumference and the following blood parameters: total cholesterol, LDL-cholesterol, HDL-cholesterol, triacylglycerols (TAG), free fatty acids, C-reactive protein, fasting insulin, fasting glucose and leptin. Insulin resistance and β-cell function were assessed using homeostatic model assessment (HOMA) and the newer computer models HOMA2-insulin sensitivity and HOMA2-β-cell function. Results: While all groups lost similar amounts of weight (4.2 to 6.2% of initial weight, p=0.09), the proportion who lost >5% of body weight varied significantly by diet: 31%, 56%, 66% and 33% in groups 1, 2, 3 and 4 respectively (p=0.011). Differences were strongest in women (76% of the total group) who showed significant differences among groups in percentage weight change (-3.7 ± 0.6%, -5.7 ± 0.6%, -6.5 ± 0.5%, -4.1 ± 0.7% respectively, p=0.005) and fat loss (-3.1 ± 0.4kg, -4.9 ± 0.6kg, -4.8 ± 0.4kg, -3.6 ± 0.7kg respectively, p=0.007). Total and LDL-cholesterol increased on DIET 3 (high protein) compared to a fall on diet 2 (high carbohydrate/low-GI, p=0.013). TAG, HDL-cholesterol and glucose homeostasis improved on all four diets, with no effect of diet composition. Goals for energy distribution were not achieved exactly: both carbohydrate groups ate less fat and the diet 2 group ate more fibre. Conclusions: Reducing GL, through either substituting low-GI foods or replacing some carbohydrate with protein, improved the efficacy of a reduced-fat diet in women and in those with high TAG. Combining both approaches to produce the lowest GL did not promote further weight or body fat loss. Although weight loss was similar in all four diets for the group as a whole, overall clinical outcomes were superior on the high carbohydrate, low-GI diet.

Thesis (M.A.)--University of Canterbury, 2008. / Typescript (photocopy). Includes bibliographical references (leaves 80-95). Also available via the World Wide Web.

Thesis (Ed.D.)--Teachers College, Columbia University, 1995. / Includes tables. Typescript; issued also on microfilm. Sponsor: Isabel Contento. Dissertation Committee: Sharon R. Akabas. Includes bibliographical references (leaves 206-215).

Thesis (M.S.)--University of Michigan, 1989.

Thesis (M.S.)--University of Michigan, 1989.