Saudi Cultural Missions Theses & Dissertations
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Item Restricted The Role of RIPK1 Pathways in Obesity and Circadian Rhythm Regulation(Saudi Digital Library, 2025) Alammar, Abdulaziz Mohammed A; Denuja, Karunakaran; Masaaki, SatoRIPK1 and MLKL are best known for executing necroptosis, yet emerging evidence implicates them in metabolic control. We tested whether modulating these proteins reshapes adipose biology and glucose regulation through non-lethal signalling. Using complementary in vivo and in vitro approaches, we combined adipose-targeted genetic manipulation with longitudinal metabolic phenotyping, depot-level endpoints, 3T3-L1 adipogenesis assays, and circadian profiling of hepatic clock-linked transcripts. Attenuating RIPK1 signalling aligned with reduced inflammatory tone in adipose tissue and indices consistent with improved insulin sensitivity, in keeping with RIPK1’s scaffolding of NF-κB pathways that antagonise insulin signalling. Effects on fat distribution favoured a relative reduction in visceral depots rather than a simple fall in total adiposity, suggesting qualitative remodelling of adipose function. MLKL influenced adipocyte programs beyond cell death: loss of MLKL impaired differentiation in vitro and pointed to altered lipid-handling pathways in vivo. Rhythmic analyses supported genotype-dependent modulation of hepatic transcripts, compatible with feedback between lipid status and clock-controlled transcription. Together, these data support a model in which RIPK1 and MLKL shape immunometabolic signalling and insulin sensitivity via context-dependent, non-necroptotic functions. The findings motivate depot-aware and time-of-day interventions and prioritise follow-up experiments coupling RIPK1 inhibition or MLKL manipulation with direct measures of PPARγ targets, adiponectin multimers, and responses to inflammatory challenge.Item Restricted Metabolic and Molecular Changes in Visceral Obesity(Saudi Digital Library, 2025) Alotaibi, Mohammed I; Murphy, David; Greenwood, MichaelRodent models have played a crucial role in obesity research, particularly for understanding polygenic obesity, which mirrors human obesity more closely than monogenic forms. The genetically diverse outbred Crl:CD SD rats provide a relevant system for studying obesity-related metabolic changes. This study categorized male Crl:CD SD rats into overweight, average-weight, and underweight groups based on body weight percentiles. Without intervention, the overweight rats exhibited increased food intake, adiposity, hyperinsulinemia, hyperglycemia, and hyperleptinemia, reinforcing their suitability for studying polygenic obesity. Expanding on these findings, a multi-omics approach was employed to investigate molecular differences in epididymal white adipose tissue (EWAT). Proteomics, phospho-proteomics, and kinase activity assays revealed significant alterations in adipogenesis pathways, cell cycle regulation, inflammatory markers, and insulin signaling. Notably, overweight rats demonstrated increased activity of the dual specificity mitogen activated protein kinase 7 (MKK7) and the never in mitosis gene A (NEK2), alongside hyperphosphorylation of O-GlcNAcase (OGA) at serine 364. To further assess the functional roles of these proteins, gene knockdown experiments were conducted in 3T3-L1 adipocytes. While Mkk7 knockdown did not impair adipogenesis, it influenced cytokine production, suggesting a role in adipose tissue inflammation. Conversely, Oga knockdown resulted in reduced cell viability and impaired adipogenesis, highlighting its importance in adipocyte differentiation. Taken together, these findings establish Crl:CD SD rats as a valuable model for studying polygenic visceral obesity and its molecular underpinnings. Additionally, MKK7 and OGA emerge as potential therapeutic targets for mitigating adipose tissue inflammation and visceral adiposity, though further in vivo studies are required to elucidate their specific mechanisms.Item Restricted Development of a home based resistance exercise programme for muscle strength and function during weight loss(Saudi Digital Library, 2025) Binmahfoz, Ahmad; Gray, StuartThesis abstract Background The prevalence of obesity continues to increase, representing a major public health concern across the globe. While dietary interventions can reduce body mass, the concurrent loss of fat free mass and muscle strength is a potentially deleterious consequence. Resistance exercise may help preserve muscle mass and function during weight loss, yet its implementation remains challenging. This thesis investigated the potential of home-based resistance exercise to attenuate these deleterious effects of weight loss through three research studies. Methods Study 1 included a systematic review and meta-analysis examining the effects of resistance exercise on body composition, muscle strength, and cardiometabolic health during dietary weight loss. Study 2 employed qualitative methods to explore experiences and perceptions of resistance exercise among people living with overweight or obesity (n=11), informing a theory of change for intervention development. Study 3 evaluated the effects of a 12-week home-based resistance exercise intervention, during dietary weight loss, through a randomised controlled pilot trial (n=48). Results The systematic review and meta-analysis (25 RCTs) demonstrated that supervised resistance exercise during dietary weight loss preserved fat free mass (SMD: 0.40, p<0.001), increased fat mass loss (SMD: -0.36, p<0.001), and improved muscle strength (SMD: 2.36, p<0.001) relative to a no exercise control. The qualitative study identified multiple barriers, including pandemic-related limits, access to facilities and financial constraints to traditional gym-based resistance exercise, and indicated strong preferences for home-based alternatives. The pilot trial showed that, during weight loss, home-based resistance training improved grip strength (p=0.046), knee extensor maximal voluntary contraction force (p=0.019) and sit-to-stand performance (p<0.001), but did not have any effects on body composition (body mass index, total body mass, fat mass, fat free mass, muscle thickness) compared to dietary weight loss alone. Conclusions The current thesis demonstrates that supervised resistance exercise enhances the benefits of diet induced weight loss by preserving muscle mass and improving muscle function. The development and evaluation of a home-based programme showed promising results for overcoming traditional barriers to resistance exercise participation and improving muscle strength and function, but not muscle mass. These findings support the implementation of accessible resistance exercise interventions during weight loss for people living with overweight or obesity.Item Restricted Obesity is linked to remodelling of mitochondrial dynamics and the inflammasome in the heart(The University of Manchester, 2025) Albalawi, Zainab; Kitmitto, AshrafBackground: Obesity affects 890 million adults worldwide, with the number of obese people predicted to rise to 1 billion by 2030. Obesity is a common precursor to type 2 diabetes (T2DM) both of which are driving the prevalence of Heart Failure with preserved Ejection Fraction (HFpEF). HFpEF has few treatment options in part due to a limited understanding of the pathophysiological processes. This thesis took a combined in-vivo and in-vitro approach to characterise the intersection between changes to cardiac function, mitochondrial dynamics and the inflammasome resulting from diet-induced obesity (DIO) (a longitudinal study), and the effects of associated stressors. The experimental findings additionally led to investigations of the protein MIRO1 (a regulator of mitochondrial motility in neuronal cells), as little is known about the role of this protein in heart health. Methods and Results: 8-week-old C57BL/6J male mice were fed either a 60% High Fat Diet (HFD) or normal chow diet for 16 or 19 weeks. After 16 weeks, the HFD mice developed hyperglycaemia and hyperinsulinemia. Cardiac structure and function, as assessed by echocardiography and electrocardiography (ECG), revealed mild impairment of systolic function, associated with eccentric hypertrophy with no changes to the ECG. Western blotting and RT-qPCR showed a shift towards fission, with a reduction in mitochondrial fusion proteins MFN1 and MFN 2 (~0.6-fold, p = 0.04 and p = 0.05, respectively). Levels of MIRO1 also fell ~2-fold (p=0.0005). In contrast to expectations, extending the HFD protocol to 19-weeks did not affect cardiac function relative to control mice. Furthermore, at 19 weeks there was a shift towards increased fusion (up-regulation of the fusion proteins MFN1 and OPA1 and down-regulation of the fission protein DRP1). Interestingly, the mitophagy proteins PINK1 and PARKIN mirrored changes detected in the 16 week model (up and down-regulation respectively). Protein levels for the NLRP3 inflammasome components increased. Proteomics analysis of isolated cardiac mitochondria (19 weeks) identified increased expression of proteins regulating ketogenic activity. In-vitro (H9C2) cytokine treatments had mixed effects on cardiomyocytes. IL-1β treatment did not affect the mitochondrial and inflammasome proteins, whereas IL-6 and TNF-ɑ affected expression level changes to inflammasome related proteins (NLRP3 and Caspase 1) and proteins linked to mitophagy (PARKIN) and mitochondrial motility (MIRO1 and MIRO2). A cardiac specific MIRO1 knockout mouse (Cre-loxP) was next developed. Partial deletion of MIRO1, Cre+Het (heterozygous), mice exhibited mild diastolic dysfunction, which was exacerbated in the MIRO1cKO (homozygous) model. Mitochondrial function of MIRO1cKO mice was assessed using a high-resolution respirometer (Oxygraph) and displayed impaired oxidative phosphorylation and increased levels of mitochondrial reactive oxygen species (ROS) relative to wild type (WT) mice. Tissue from the apex of MIRO1cKO hearts was fixed for Transmission electron microscopy (EM) revealing more interfibrillar (IFM) and subsarcolemma (SSM) mitochondria with disrupted cristae, consistent with increased Cytochrome C expression compared to WT mice. Cre+Het mice when given a combination of a 60% HFD and L-NAME, when compared to control mice, exhibited a rapid onset of cardiac dysfunction consistent with HFpEF pathophysiology. Conclusion: This Thesis work developed and characterised a DIO mouse model that reiterated features of HFrEF, identifying a shift towards mitochondrial fission. Surprisingly, extending the HFD duration resulted in a reversion of the cardiac dysfunction to a healthy cardiac phenotype. This finding afforded the opportunity to compare the 16 and 19 week models at the molecular level to identify mitochondrial proteins that exhibited plasticity and thus may be linked to the pathogenesis of HF. For example, the shift from fission to fusion could suggest that promoting fusion improves cardiac outcomes. Additionally, upregulation of the ketogenesis pathway proteins was also identified at 19 weeks, suggesting HMGCS2 and BDH1 linked processes may represent intervention pathways. The link between obesity and inflammation status emerged as complex and further studies are required for clear stratification to HFrEF progression. This thesis also generated novel data revealing that the protein MIRO1 plays a crucial role in cardiac function and loss of MIRO1 leads to cardiac and mitochondrial dysfunction and altered the mitochondrial morphology. When combined, the novel results from this Thesis research have identified potential new target candidates/directions for developing novel approaches to preventing/delaying obesity-linked HF and serve as a platform for future investigation.Item Restricted Benefits of Supplementation with LCn-3 PUFA during Diet-Induced Body Mass Loss and Maintenance Phases on Body Composition, Muscle Function, and Appetite(University Of Glasgow, 2025) Alblaji, Mansour Ghazi; Malkova, Dalia; Gray, StuartObesity is a complex medical condition that is associated with a range of comorbidities, including hypertension, type 2 diabetes, dyslipidaemia, gastrointestinal disorders, joint pain, and musculoskeletal complications. Current treatment approaches for obesity primarily involve lifestyle modifications, including diet-induced weight loss and physical exercise. However, evidence from previous research highlights a concern regarding diet-induced body mass loss: approximately 25–30% of the total body mass lost is derived from fat-free mass (FFM). This decline in FFM is associated with diminished muscle mass and function, reduced metabolic rate, and an elevated risk of body mass regain. Attenuating FFM loss during body mass loss is therefore critical for healthy body mass loss. Long-chain n-3 polyunsaturated fatty acids (LCn-3 PUFA) have been proposed as a potential strategy to mitigate these effects by influencing body composition, muscle mass and function, and inflammation during energy balance. Evidence suggests that LCn-3 PUFA can reduce fat mass while enhancing FFM, improving muscle mass, strength, and function, and mitigating inflammation. However, despite these potential benefits, the evidence supporting the efficacy of LCn-3 PUFA supplementation during diet-induced body mass loss on body composition, muscle function, and inflammatory markers remains limited and requires further exploration. The first aim of this thesis was to systematically investigate the effects of supplementation with LCn-3 PUFA during caloric restriction (CR) on body mass, fat mass and FFM loss (Chapter 2). Eleven studies were included in this systematic review and meta-analysis as they met the inclusion criteria of the systematic review, with a total of 637 participants. The participants’ age ranged between 18 and 61 years, with a mean BMI ranging between 27 and 36 kg/m2 . Pooled analyses showed that LCn-3 PUFA supplementation during CR had no additional effect on changes in body mass (SMD = -0.05: 95% CI -0.22 to 0.13; p = 0.62; I2 : 10%), BMI (SMD = -0.06, 95% CI -0.25 to 0.13; p = 0.55; I2 : 18%), fat mass (SMD = - 0.01; 95% CI -0.25 to 0.24; p = 0.96; I2 : 46%), or FFM (SMD = 0.12, 95%CI -0.14 to 0.37, p = 0.36; I2 :35%). The lack of impact of LCn-3 PUFA on body mass and composition observed in this systematic review (Chapter 2) may be attributed to some limitations in the iii included studies. Most of the studies assessed body composition using bioelectrical impedance analysis (BIA), applied low doses of LCn-3 PUFA, and also did not evaluate muscle strength during diet-induced body mass loss. To address the gaps identified in our systematic review, a double-blind, randomised, placebo-controlled trial (RCT) was conducted, including a 4-week preparation phase, an 8-week alternate-day fasting (ADF) phase, and an 8-week body mass maintenance phase, with participants taking 4 capsules/day of krill oil as a source of LCn-3 PUFA throughout (Chapter 4). Body composition was evaluated via the deuterium water (D2O) dilution method, and parameters of muscle function, and fasting blood samples were measured at the pre- and post body mass loss phase. Forty-one healthy adults completed this RCT. The two-way ANOVA revealed significant time and time*group interaction effects on FFM, handgrip strength, chair rising test, TNF-α, CRP, and systolic blood pressure (all p < 0.05). Post-intervention, there was a small, non-significant reduction in FFM (- 0.2 ± 0.9 kg, p > 0.05) and handgrip strength (-0.2 ± 0.5 kg, p > 0.05) in the krill oil group, whereas the placebo group experienced significant reductions in FFM (- 1.2 ± 2.0 kg, p < 0.05) and handgrip strength (-0.9 ± 0.7 kg, p < 0.05). The time to conduct the chair rising test decreased significantly in the krill oil group (-1.8 ± 0.9 s, p < 0.05), whereas the reduction in the placebo group was not significant (- 0.3 ± 1.2 s, p > 0.05). TNF-α levels decreased significantly in both groups (all p < 0.05), with a greater reduction in the krill oil group (-1.4 ± 0.2 pg/ml) compared to the placebo group (-0.9 ± 0.5 pg/ml). Similarly, CRP levels were significantly reduced in both groups (all p < 0.05), with a greater reduction in the krill oil group (-51.4 ± 25 ng/ml) than in the placebo group (-33.5 ± 12.6 ng/ml). Systolic blood pressure decreased significantly in both groups (all p < 0.05), with a greater reduction observed in the krill oil group (-9 ± 6 mmHg) compared to the placebo group (-4 ± 4 mmHg). No significant difference was observed in changes between groups in body mass, body fat, insulin, glucose HOMA-IR, TAG, or diastolic blood pressure (all p > 0.05). Therefore, from this RCT, it was concluded that supplementation with krill oil during diet-induced body mass loss via ADF helps to attenuate the associated decline of FFM and muscle function, improve functional capacity, and reduce TNF-α and CRP levels. Supplementation with LCn-3 PUFA, in the absence of CR, has been associated with appetite reduction and enhanced sensations of fullness and satiety in individuals iv living with overweight or obesity. However, the effects of LCn-3 PUFA supplementation during diet-induced body mass loss on appetite and gastrointestinal appetite hormones remain underexplored. In Chapter 5, the impact of LCn-3 PUFA during diet-induced body mass loss on changes in appetite and gastrointestinal appetite hormones was examined in a subset of the participants of the RCT (Chapter 4). This exploratory study included 28 adults (mean age: 39.4 ± 11.7 years; BMI: 27.9 ± 3.2 kg/m²) who participated in the RCT (Chapter 4). Body mass, body fat, and FFM were measured at baseline (week 4), at the end of the body mass loss phase (week 12), and at the end of the body mass maintenance phase (week 20). Fasting and postprandial subjective appetite scores, along with plasma concentrations of acylated ghrelin, Glucagon-Like Peptide-1 (GLP-1), and Peptide YY (PYY), were assessed before and after the body mass loss phase. The ANOVA revealed a significant time (p<0.05), but not group (p>0.05) or time*group interaction (p>0.05) effects for body mass, fat mass or FFM during the body mass loss phase. During the maintenance phase, no significant (p>0.05) time, group, or time*group interaction effects were found for body mass and FFM, but for fat mass, a significant time*group interaction effect was observed (p<0.05). During the maintenance phase, in the krill oil group, fat mass remained unchanged (p>0.05) but increased significantly (p< 0.05) in the placebo group. This coincided with the body mass loss-induced significant reduction (p<0.05) in the composite appetite score (CAS) in the krill oil but not the placebo group (p> 0.05). There was no significant (p>0.05) time, group, or time*group interaction effects for acylated ghrelin, GLP-1, and PYY during the body mass loss phase. Changes in body mass during the body mass loss and body mass maintenance phases were not correlated with acylated ghrelin, PYY, or GLP-1 (all p > 0.05). Body mass changes during the body mass loss phase showed a tendency toward a significant positive correlation with changes in CAS (r=0.36, p = 0.06). Therefore, krill oil supplementation during body mass maintenance may induce favourable changes in subjective appetite and prevent short-term fat mass regain. Overall, the current thesis demonstrates that supplementing with LCn-3 PUFA during diet-induced body mass loss is a promising strategy to attenuate the loss of FFM and muscle function. Beyond these benefits, LCn-3 PUFA supplementation also reduces inflammation and lowers blood pressure, underscoring its potential to enhance body composition, preserve muscle mass, and promote overall well- v being during body mass loss. Furthermore, LCn-3 PUFA supplementation may reduce subjective appetite and might help to prevent fat mass regain during the body mass maintenance phase, further supporting its role in long-term body mass management.Item Restricted Age-Varying Associations Between Childhood Abuse and The Risk of Obesity Across Adulthood: Examining Data from The National Longitudinal Study of Adolescents to Adult Health(Claremont Graduate University, 2025) Abudawood, Mohammed; Xie, BinChildhood abuse is a significant early-life stressor linked to adverse health outcomes such as obesity across adulthood. This study examines how the association between childhood abuse (physical, emotional, and sexual) and obesity risk varies with age, using data from Waves I–V of the National Longitudinal Study of Adolescents to Adult Health (Add Health). Utilizing Time-Varying Effect Modeling (TVEM), the study identifies specific developmental periods during which the relationship between childhood abuse and obesity risk is strongest and investigates the moderating role of gender. The study found that all forms of childhood abuse are associated with elevated obesity risk across the life course, with distinct patterns over time. Physical abuse showed a stronger impact on obesity risk during late adolescence and early adulthood, with a resurgence of influence in later adulthood. Emotional abuse had a positive and long-lasting association with obesity risk from young adulthood into established adulthood. Sexual abuse was linked to increased obesity risk emerging in late adolescence, early adulthood, and established adulthood, with females experiencing particularly pronounced effects in early adulthood. These results highlight the temporal dynamics of childhood abuse on obesity risk across adulthood, offering critical insights for the timing and tailoring of prevention and intervention strategies. The study underscores the need for trauma-informed public health policies that address childhood abuse as a risk factor for obesity across adulthood, particularly at high-risk age windows. By identifying when and for whom the abuse-obesity link is strongest, this study informs more effective prevention strategies and health policies to mitigate long-term obesity risk among survivors of childhood abuse.17 0Item Restricted UNDERSTANDING THE RELATIONSHIP BETWEEN WEIGHT MANAGEMENT SUCCESS AND FOOD CRAVINGS: INVESTIGATING STRATEGIES(University of Illinois Urbana-Champaign, 2027-12-20) Alfouzan, Nouf; Nakamura, ManabuIntroduction: Obesity and its related comorbidities have become one of the significant threats to public health. While sustained weight loss can mitigate these comorbidities, achieving and maintaining weight loss remains challenging. One of the significant challenges in sustaining weight loss is managing food cravings, as uncontrolled cravings are associated with increased intake of calorie-dense foods and subsequent weight regain. The goals were to determine the impact of weight loss and maintenance on food cravings and identify effective strategies for managing food cravings that could prevent weight regain. The objective of study 1 was to determine the associations of factors such as food cravings and eating habits with large variations in weight loss and maintenance outcomes. The objective of study 2 was to evaluate the long-term change in food cravings, whether food cravings changes persist during weight maintenance, and explore the relationship between food cravings changes and weight loss outcomes. The objective of the final study was to determine whether an avoidance strategy or an inclusion strategy is more effective in reducing food cravings and achieving a greater magnitude of weight loss. Methods: Study 1 was a one-year follow-up study conducted after completing a one-year dietary weight loss program. Twenty-two participants entered the follow-up phase and weighed themselves daily using Wi-Fi scales. Self-reported questionnaires assessing food cravings and eating habits were collected at 12 and 24 months. In study 2, thirty participants with a BMI of 25 kg/m² enrolled in a one-year weight loss dietary program, EMPOWER, followed by one year of weight maintenance. Self-reported food craving questionnaires were completed at baseline, 6, 12, 18, and 24 months. At 12 months, participants reported their experience using the "inclusion strategy" for managing food cravings and rated its frequency and effectiveness in supporting weight loss goals and controlling food cravings. Daily self-weighing was recorded using Wi-Fi scales. In the final study, sixty-three adults with a BMI of 28 kg/m², who reported moderate food cravings and the consumption of craved foods a few times a week, participated in a 3-month EMPOWER program. Participants were randomized into one of two food craving management strategies: avoidance or inclusion. The avoidance strategy involves completely avoiding craved foods by reducing their availability and accessibility, while the inclusion strategy incorporates small portions of craved foods within well-balanced meals and avoids their consumption between meals. Self-reported food craving questionnaires were completed at baseline and 3 months, along with bi-weekly self-reported treatment adherence. Daily self-weighing was reported using Wi-Fi scales. Body composition and anthropometric measurements were taken at baseline and 3 months. Monthly self-reported dietary intake was assessed, and weekly feedback messages from nutrition coaches were provided to monitor progress in weight loss and food craving management. Results: In study 1, 19 out of 22 (86.3%) completed the questionnaires at 12 and 24 months. Control food cravings at 12 and 24 months was significantly associated with weight loss outcomes; those in the >5% weight loss group had higher food craving control compared to the <5% group (3.23 vs. 2.72, p = 0.03; 3.48 vs. 2.72, p = 0.01, respectively). Self-perceived implementation of maintaining consistent portion sizes significantly correlates with weight loss outcomes at 24 months (r=0.76, p=0.0001). In study 2, out of 30 participants, 24 (80%) remained in the program at 12 months with an average (SD) weight loss of -7.9 (7.2 %) and 20 (66.7%) completed the program at 24 months with a mean weight loss of -6.7 (7.5 %). The frequency of general food cravings and cravings for specific foods and craving traits decreased significantly at 12 and 24 months from baseline and remained stable from 12 to 24 months. Changes in food cravings at 6 months predict concurrent and subsequent weight changes at 12, 18, and 24 months. Participants who implemented the inclusion strategy (n = 16) experienced significantly greater weight loss (-9.9% vs. -3.7%, p = 0.04), reduced cravings for high-fat foods (-0.50 vs. -0.09, p = 0.02), and sweet foods (-1.02 vs. -0.38, p = 0.028) compared to non-strategy users (n = 8) at 12 months. In the final study, 56 of 63 participants (88.9 %) completed the 3-month EMPOWER program, with a mean weight loss of -3.55(3.21 %). There was no significant difference in weight loss between the groups (p=0.67), with the avoidance group's average weight loss of -3.73 (3.34 %) (n=28) and the inclusion group's average weight loss of -3.36(3.34 %) (n=28). Compared to the avoidance group, the inclusion group showed greater reductions in cravings for carbohydrates (p = 0.01), high-fat foods (p = 0.03), and general food cravings (p = 0.05). The inclusion group also had significant improvements in global trait scores (p = 0.04) and specific traits such as "anticipation of relief from the negative state" (p = 0.03), "craving as a physiological state" (p = 0.04), and "guilt from cravings" (p = 0.04). In the inclusion group, craving frequency and strength steadily decreased from Week 2 to Week 12, whereas in the avoidance group, cravings initially decreased from Week 2 to Week 4 but then increased. Conclusion: In study 1, reduced food cravings were correlated with successful weight maintenance. In study 2, food cravings and cravings for specific foods decreased during weight loss, and remained stable during weight maintenance, with craving reduction demonstrating a strong correlation to successful weight loss and maintenance. In the final study, the inclusion strategies resulted in a greater reduction in food cravings and cravings for specific foods compared to the avoidance strategy.21 0Item Restricted UNDERSTANDING THE RELATIONSHIP BETWEEN WEIGHT MANAGEMENT SUCCESS AND FOOD CRAVINGS: INVESTIGATING STRATEGIES(UNIVERSITY OF ILLINOIS URBANA CHAMPAIGN, 2024) ALFOUZAN, NOUF; NAKAMURA, MANABUIntroduction: Obesity and its related comorbidities have become one of the significant threats to public health. While sustained weight loss can mitigate these comorbidities, achieving and maintaining weight loss remains challenging. One of the significant challenges in sustaining weight loss is managing food cravings, as uncontrolled cravings are associated with increased intake of calorie-dense foods and subsequent weight regain. The goals were to determine the impact of weight loss and maintenance on food cravings and identify effective strategies for managing food cravings that could prevent weight regain. The objective of study 1 was to determine the associations of factors such as food cravings and eating habits with large variations in weight loss and maintenance outcomes. The objective of study 2 was to evaluate the long-term change in food cravings, whether food cravings changes persist during weight maintenance, and explore the relationship between food cravings changes and weight loss outcomes. The objective of the final study was to determine whether an avoidance strategy or an inclusion strategy is more effective in reducing food cravings and achieving a greater magnitude of weight loss. Methods: Study 1 was a one-year follow-up study conducted after completing a one-year dietary weight loss program. Twenty-two participants entered the follow-up phase and weighed themselves daily using Wi-Fi scales. Self-reported questionnaires assessing food cravings and eating habits were collected at 12 and 24 months. In study 2, thirty participants with a BMI of 25 kg/m² enrolled in a one-year weight loss dietary program, EMPOWER, followed by one year of weight maintenance. Self-reported food craving questionnaires were completed at baseline, 6, 12, 18, and 24 months. At 12 months, participants reported their experience using the "inclusion strategy" for managing food cravings and rated its frequency and effectiveness in supporting weight loss goals and controlling food cravings. Daily self-weighing was recorded using Wi-Fi scales. In the final study, sixty-three adults with a BMI of 28 kg/m², who reported moderate food cravings and the consumption of craved foods a few times a week, participated in a 3-month EMPOWER program. Participants were randomized into one of two food craving management strategies: avoidance or inclusion. The avoidance strategy involves completely avoiding craved foods by reducing their availability and accessibility, while the inclusion strategy incorporates small portions of craved foods within well-balanced meals and avoids their consumption between meals. Self-reported food craving questionnaires were completed at baseline and 3 months, along with bi-weekly self-reported treatment adherence. Daily self-weighing was reported using Wi-Fi scales. Body composition and anthropometric measurements were taken at baseline and 3 months. Monthly self-reported dietary intake was assessed, and weekly feedback messages from nutrition coaches were provided to monitor progress in weight loss and food craving management. Results: In study 1, 19 out of 22 (86.3%) completed the questionnaires at 12 and 24 months. Control food cravings at 12 and 24 months was significantly associated with weight loss outcomes; those in the >5% weight loss group had higher food craving control compared to the <5% group (3.23 vs. 2.72, p = 0.03; 3.48 vs. 2.72, p = 0.01, respectively). Self-perceived implementation of maintaining consistent portion sizes significantly correlates with weight loss outcomes at 24 months (r=0.76, p=0.0001). In study 2, out of 30 participants, 24 (80%) remained in the program at 12 months with an average (SD) weight loss of -7.9 (7.2 %) and 20 (66.7%) completed the program at 24 months with a mean weight loss of -6.7 (7.5 %). The frequency of general food cravings and cravings for specific foods and craving traits decreased significantly at 12 and 24 months from baseline and remained stable from 12 to 24 months. Changes in food cravings at 6 months predict concurrent and subsequent weight changes at 12, 18, and 24 months. Participants who implemented the inclusion strategy (n = 16) experienced significantly greater weight loss (-9.9% vs. -3.7%, p = 0.04), reduced cravings for high-fat foods (-0.50 vs. -0.09, p = 0.02), and sweet foods (-1.02 vs. -0.38, p = 0.028) compared to non-strategy users (n = 8) at 12 months. In the final study, 56 of 63 participants (88.9 %) completed the 3-month EMPOWER program, with a mean weight loss of -3.55(3.21 %). There was no significant difference in weight loss between the groups (p=0.67), with the avoidance group's average weight loss of -3.73 (3.34 %) (n=28) and the inclusion group's average weight loss of -3.36(3.34 %) (n=28). Compared to the avoidance group, the inclusion group showed greater reductions in cravings for carbohydrates (p = 0.01), high-fat foods (p = 0.03), and general food cravings (p = 0.05). The inclusion group also had significant improvements in global trait scores (p = 0.04) and specific traits such as "anticipation of relief from the negative state" (p = 0.03), "craving as a physiological state" (p = 0.04), and "guilt from cravings" (p = 0.04). In the inclusion group, craving frequency and strength steadily decreased from Week 2 to Week 12, whereas in the avoidance group, cravings initially decreased from Week 2 to Week 4 but then increased. Conclusion: In study 1, reduced food cravings were correlated with successful weight maintenance. In study 2, food cravings and cravings for specific foods decreased during weight loss, and remained stable during weight maintenance, with craving reduction demonstrating a strong correlation to successful weight loss and maintenance. In the final study, the inclusion strategies resulted in a greater reduction in food cravings and cravings for specific foods compared to the avoidance strategy.9 0Item Restricted Bariatric Surgery and Its Impact on Taste Perception and Preference: A Systematic Review(University of Nottingham, 2024-09-02) Alsaud, Alhanoof; Eldeghaidy, SallyBackground: Changes in taste perception and food preferences could play a significant role in driving dietary modifications and facilitating weight loss following bariatric surgery. These sensory alterations may influence the types of food patients are inclined to consume post-surgery, potentially leading to healthier eating patterns that support sustained weight reduction. Objective: to assess variations in taste thresholds, in the intensity and quality of taste sensations and in changes to food preferences following bariatric surgery. Methodology: A systematic review was conducted using databases such as PubMed, Scopus, and Web of Science to identify studies examining changes in taste perception and preferences following bariatric surgery. Inclusion criteria were set to include studies with pre- and post-surgery taste perception and preference measurements. Data were extracted and synthesised to highlight changes assess variations in taste perception and food preferences. Result: The review included 12 studies, found that bariatric surgery lead to significant taste changes in taste thresholds, intensity and quality. Alterations in taste thresholds, including increased or decreased sensitivity for sweetness, bitterness, and saltiness, and the hedonic value of food that reduce enjoyment of high-calorie and high-fat food were commonly reported. Changes in food preference often shifted toward healthier choices, with reduced cravings for sweet and fat and increased intake of fruits and vegetables. However, these changes were not always sustained over time. Potential mechanisms also mentioned which involve hormonal changes, neurobiological adaptations in brain reward system, and inflammatory responses. Conclusion: Current evidence indicates that bariatric procedures lead to significant changes in taste perception and food preference, which may play a critical role in supporting the long-term maintenance of weight loss after bariatric surgery. Future research should include extended follow-up and investigate the mechanism behind this change to better understand the long-term effect of taste alteration and dietary changes.14 0Item Restricted An evaluation of the Rashaka Initiative: a school-based obesity intervention in Makkah City, Saudi Arabia(University of Technology Sydney, 2024-03) Banany, Mohammed; Sibbritt, David; Gebel, KlausBackground: Childhood overweight and obesity are public health issues worldwide. In Saudi Arabia, in 2016/2017 the Rashaka Initiative, a national school-based, multicomponent, weight-related intervention, was launched to decrease the prevalence of obesity among students by 5% within five years. Neither the development stage of the initiative nor its implementation has been evaluated to explore its processes and outcomes. Aim: This study was aimed at evaluating the implementation of the Rashaka Initiative in intermediate and secondary schools in Makkah City, Saudi Arabia, covering both process and outcome. To this end, the following objectives were pursued: (1) to develop an evaluation framework that can be used to assess the processes and outcomes of the initiative, (2) to determine whether there was a change in students’ body mass indices (BMIs) during the implementation period, and (3) to explore the knowledge and attitudes of the Rashaka stakeholders regarding the perceived barriers and facilitators of implementation in their schools. Methods: This retrospective study, conducted after the implementation of the Rashaka Initiative, was completed in three phases. In phase I, a conceptual framework called the school-based weight-related intervention evaluation framework (SWIEF) was developed by integrating some elements of the program evaluation framework used by the US Centers for Disease Control and Prevention (CDC) with the components of a logic model. In phase II, secondary data from the Rashaka Initiative were analysed. Phase III was a cross-sectional exploration of the Rashaka stakeholders’ knowledge and attitudes as well as what they perceive as facilitators and barriers to implementing the intervention at their schools. Results: The comprehensive literature review yielded a published systematic review (Banany et al. 2024, Systematic Reviews). This systematic review found 11 school-based weight-related intervention studies in the six Gulf Cooperation Council countries (GCC). Despite the methodological limitations of some of these studies, there is preliminary evidence of the possible benefits of school-based interventions on students' weight and associated lifestyle factors in these countries. A review of the literature also facilitated the development of the SWIEF. The analysis of the secondary data revealed a significant reduction in BMI (p<0.001) across schools that participated in the Rashaka Initiative over two school years (2016/17 and 2018/19). However, this reduction was not associated with the school environmental factors attributed to the initiative. The study findings found that students’ BMIs decreased more considerably in girls’ and intermediate schools than in boys’ and secondary schools (p<0.001 and p=0.031, respectively). The cross-sectional study indicated that significantly better knowledge of risk factors and interventions for childhood obesity was exhibited by female Rashaka stakeholders (vs their male counterparts), stakeholders who completed tertiary education (vs those with lower education levels) and stakeholders engaged in the initiative for more than two years (vs participants who joined more recently) (p<0.001, p<0.007 and p<0.033, respectively). School health counsellors had more positive attitudes towards children’s health and weight than principals (p<0.008). Significantly more favourable attitudes towards the Rashaka intervention were also found among female stakeholders (p<0.011) and those with better knowledge of the initiative’s objectives, components, activities, and outcomes (p<0.049). Among the stakeholders, 73% perceived collaboration with different government and private sector institutions as the most common facilitator of the Rashaka implementation at their schools, while 69% perceived a lack of time as the main barrier. Conclusions: Addressing childhood obesity is a public health priority that requires substantial efforts from all relevant key stakeholders in Saudi Arabia. The evidence derived in this thesis revealed that the Rashaka Initiative has yet to satisfy its objectives. Future studies should be more rigorous, theory-based, and holistic to tackle obesity among school students. Evaluations of school-based obesity interventions should use control groups, validated and reliable measures and rigorous data analysis. Long-term monitoring of the implemented interventions is highly recommended for their improvement and sustainability.80 0
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