Matching Items (18)
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- All Subjects: Obesity
- Creators: Herman, Richard
- Creators: Shaibi, Gabriel
Description
Cardiovascular disease (CVD) is the number one cause of death in the United States and type 2 diabetes (T2D) and obesity lead to cardiovascular disease. Obese adults are more susceptible to CVD compared to their non-obese counterparts. Exercise training leads to large reductions in the risk of CVD and T2D. Recent evidence suggests high-intensity interval training (HIT) may yield similar or superior benefits in a shorter amount of time compared to traditional continuous exercise training. The purpose of this study was to compare the effects of HIT to continuous (CONT) exercise training for the improvement of endothelial function, glucose control, and visceral adipose tissue. Seventeen obese men (N=9) and women (N=8) were randomized to eight weeks of either HIT (N=9, age=34 years, BMI=37.6 kg/m2) or CONT (N=8, age=34 years, BMI=34.6 kg/m2) exercise 3 days/week for 8 weeks. Endothelial function was assessed via flow-mediated dilation (FMD), glucose control was assessed via continuous glucose monitoring (CGM), and visceral adipose tissue and body composition was measured with an iDXA. Incremental exercise testing was performed at baseline, 4 weeks, and 8 weeks. There were no changes in weight, fat mass, or visceral adipose tissue measured by the iDXA, but there was a significant reduction in body fat that did not differ by group (46±6.3 to 45.4±6.6%, P=0.025). HIT led to a significantly greater improvement in FMD compared to CONT exercise (HIT: 5.1 to 9.0%; CONT: 5.0 to 2.6%, P=0.006). Average 24-hour glucose was not improved over the whole group and there were no group x time interactions for CGM data (HIT: 103.9 to 98.2 mg/dl; CONT: 99.9 to 100.2 mg/dl, P>0.05). When statistical analysis included only the subjects who started with an average glucose at baseline > 100 mg/dl, there was a significant improvement in glucose control overall, but no group x time interaction (107.8 to 94.2 mg/dl, P=0.027). Eight weeks of HIT led to superior improvements in endothelial function and similar improvements in glucose control in obese subjects at risk for T2D and CVD. HIT was shown to have comparable or superior health benefits in this obese sample with a 36% lower total exercise time commitment.
ContributorsSawyer, Brandon J (Author) / Gaesser, Glenn A (Thesis advisor) / Shaibi, Gabriel (Committee member) / Lee, Chong (Committee member) / Swan, Pamela (Committee member) / Buman, Matthew (Committee member) / Arizona State University (Publisher)
Created2013
Description
Obesity in Hispanic youth has reached alarmingly high levels, increasing the risk of type 2 diabetes, hyperlipidemia, hypertension, and cardiovascular disease. In Mexican American children ages 6-11 years, 41.7% are overweight and obese, 24.7% are obese and 19.6% have a Body Mass Index (BMI) greater than the 97th percentile. While personal, behavioral, and environmental factors contribute to these high rates, emerging literature suggests acculturation, self-efficacy and social support are key influences. The one-group, pre- and post-test, quasi-experimental design used a community-based participatory research (CBPR) method to test the feasibility, acceptability, and preliminary efficacy of the 8-week intervention. Social Cognitive Theory (SCT) was used to guide the design. Measurements included an analysis of recruitment, retention, participant satisfaction, observation of intervention sessions, paired t-tests, effect sizes, and bivariate correlations between study variables (acculturation, nutrition and physical activity [PA] knowledge, attitude and behaviors, perceived confidence and social support) and outcome variables (BMI z-score, waist circumference and BP percentile) Findings showed the SSLN program was feasible and acceptable. Participants (n = 16) reported that the curriculum was fun and they learned about nutrition and PA. The retention rate was 94%. The preliminary effects on adolescent nutrition and PA behaviors showed mixed results with small-to-medium effect sizes for nutrition knowledge and attitude, PA and sedentary behavior. Correlation analysis among acculturation and study variables was not significant. Positive associations were found between perceived confidence in eating and nutrition attitude (r = .61, p < .05) and nutrition behavior (r = .62, p < .05), perceived confidence in exercise and nutrition behavior (r = .66, p < .05), social support from family for exercise and PA behavior (r = .67, p < .01) and social support from friends for exercise and PA behavior (r = .56, p < .05). These findings suggest a culturally specific healthy eating and activity program for adolescents was feasible and acceptable and warrants further investigation, since it may fill a gap in existing obesity programs designed for Hispanic youth. The positive correlations suggest further testing of the theoretical model.
ContributorsStevens, Carol (Author) / Gance-Cleveland, Bonnie (Thesis advisor) / Komnenich, Pauline (Committee member) / Shaibi, Gabriel (Committee member) / Arcoleo, Kimberly (Committee member) / Arizona State University (Publisher)
Created2011
Description
Brown adipose tissue (BAT) is thought to be important in combating obesity as it can expend energy in the form of heat, e.g. thermogenesis. The goal of this study was to study the effect of injected norepinephrine (NE) on the activation of BAT in rats that were fed a high fat diet (HFD). A dose of 0.25 mg/kg NE was used to elicit a temperature response that was measured using transponders inserted subcutaneously over the BAT and lower back and intraperitoneally to measure the core temperature. The results found that the thermic effect of the BAT increased after the transition from low fat diet to a high fat diet (LFD) yet, after prolonged exposure to the HFD, the effects resembled levels found with the LFD. This suggests that while a HFD may stimulate the effect of BAT, long term exposure may have adverse effects on BAT activity. This may be due to internal factors that will need to be examined further.
ContributorsSion, Paul William (Author) / Herman, Richard (Thesis director) / Borges, Chad (Committee member) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
Background: The prevalence of childhood obesity has disproportionately affected Latino youth and can be seen with an increase incidence of Type 2 Diabetes. This increase in obesity can be attributed to physical inactivity. Increases in social support and self-efficacy are independently related to increases in physical activity. A lifestyle intervention can lead to increases in social support, self-efficacy and physical activity. Objective/Hypothesis: The objective of this study was to determine whether a 12-week lifestyle intervention could increase social support, self-efficacy and physical activity in obese Latino adolescents that participated in the intervention. It was hypothesized that adolescents that participated in the intervention would increase self-efficacy, social support from family and friends, and physical activity compared to their control counterparts. Study Design/Participants: In a randomized control trial, there were 125 Latino (n= 60 experimental group; n= 65 control group; mean age = 15.17 +- 1.65 Males n = 60; n = 65 females) participants included in this study. Participants were also required to have a BMI percentile >= 95th percentile for age and gender or BMI >= 30 kg/m2. Methods: The intervention, which was developed using the Social Cognitive Theory had components focusing on social support and self-efficacy and also consisted of nutrition education classes and physical activity sessions for 12 weeks. The psychosocial constructs of self-efficacy and social support were measured using the Adolescent Self-Efficacy for Diet and Activity Behaviors and Adolescent Social Support for Diet and Exercise Survey, respectively. Physical activity was assessed by the 3-day Physical Activity Recall. Results: We found significant increases in social support in family (p = 0.042) and vigorous physical activity (p = 0.001). There was also a significant difference between control and treatment group for moderate to vigorous physical activity after the intervention (p = 0.027). There were no changes in social support from friends or self-efficacy. Conclusion: We concluded that a 12-week lifestyle intervention did lead to changes in social support and physical activity behaviors. These changes could have been influenced by the intervention as they were measured these constructs pre/post intervention.
ContributorsRahman, Hanna (Author) / Shaibi, Gabriel (Thesis director) / Hoffner, Kristin (Committee member) / School of Nutrition and Health Promotion (Contributor) / School of Social and Behavioral Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
There has been an alarming rise in the prevalence of obesity which has been attributed to the paralleled rise in consumption of high-fat foods. It’s commonly accepted that high-fat diets can lead to increased weight gain, however not all fats have the same physiological action. This study primarily focuses on the effect of canola oil, a monounsaturated fat, on energy homeostasis and body composition when it’s given as a supplement to a high-fat diet composed of saturated fatty acid. Rodent models were divided into three dietary groups: 1) low-fat diet (LFD), 2) high-fat diet (HFD) and 3) canola oils supplemented HFD (HF+CAN). After 4 weeks of dietary intervention, samples of epididymal fat, perinephric fat, and liver were analyzed across the three groups to see if the changes in energy homeostasis could be explained by the cellular behavior and composition of these tissues. Interestingly, the supplement of canola oil appeared to reverse the deleterious effects of a saturated fat diet, reverting energy intake, body weight gain and adipose tissue sizes to that (if not lower than that) of the LFD group. The only exception to this effect was the liver: the livers remained larger and fattier than those of the HFD. This occurrence is possibly due to a decrease in free fatty acid uptake in the adipose tissues—resulting in smaller adipose tissue sizes—and increased fatty acid uptake in the liver. The mechanism by which this occurs has yet to be elucidated and will be the primary focus of upcoming studies on the effect of monounsaturated fat on other diets.
ContributorsZuo, Connie Wanda (Author) / Washo-Krupps, Delon (Thesis director) / Deviche, Pierre (Committee member) / Herman, Richard (Committee member) / Barrett, The Honors College (Contributor) / Department of Chemistry and Biochemistry (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
Background:
Pediatric obesity is associated with lower quality of life (QOL) and populations with high obesity rates, such as Latinos, are especially vulnerable. We examined the effects of a 12-week diabetes prevention program on changes in weight-specific QOL in Latino youth.
Method:
Fifteen obese Latino adolescents (BMI%=96.3±1.1;age=15.0±1.0) completed a 12-week intervention. Youth completed weight-specific QOL measures at baseline, post intervention, and 1-year follow-up. For comparison purposes, intervention youth were matched for age and gender with lean controls.
Results:
At baseline, obese youth exhibited significantly lower weight-specific QOL compared with lean youth (70.8±5.4 to 91.2±2.2, p<0.005). The intervention did not significantly impact weight (90.6±6.8 to 89.9±7.2kg, p=0.44). However, significant increases in weight-specific QOL were observed (70.8±20.9 to 86.2±16.9, p<0.001). Post-intervention QOL scores were no longer significantly different than lean controls (P=0.692). Data from nine youth who returned for follow-up indicated that increases in weight-specific QOL were maintained over time (90.5±4.5 to 85.8±5.9, p=0.74).
Conclusion:
These results indicate that a community-based diabetes prevention program can result in sustained improvements in weight-specific QOL among obese Latino youth. Lifestyle interventions that focus on social interaction and physical activity, rather than weight-loss per se, may help improve the psychosocial health of obese Latino youth.
Pediatric obesity is associated with lower quality of life (QOL) and populations with high obesity rates, such as Latinos, are especially vulnerable. We examined the effects of a 12-week diabetes prevention program on changes in weight-specific QOL in Latino youth.
Method:
Fifteen obese Latino adolescents (BMI%=96.3±1.1;age=15.0±1.0) completed a 12-week intervention. Youth completed weight-specific QOL measures at baseline, post intervention, and 1-year follow-up. For comparison purposes, intervention youth were matched for age and gender with lean controls.
Results:
At baseline, obese youth exhibited significantly lower weight-specific QOL compared with lean youth (70.8±5.4 to 91.2±2.2, p<0.005). The intervention did not significantly impact weight (90.6±6.8 to 89.9±7.2kg, p=0.44). However, significant increases in weight-specific QOL were observed (70.8±20.9 to 86.2±16.9, p<0.001). Post-intervention QOL scores were no longer significantly different than lean controls (P=0.692). Data from nine youth who returned for follow-up indicated that increases in weight-specific QOL were maintained over time (90.5±4.5 to 85.8±5.9, p=0.74).
Conclusion:
These results indicate that a community-based diabetes prevention program can result in sustained improvements in weight-specific QOL among obese Latino youth. Lifestyle interventions that focus on social interaction and physical activity, rather than weight-loss per se, may help improve the psychosocial health of obese Latino youth.
ContributorsBrito, Elizabeth (Author) / Shaibi, Gabriel (Thesis director) / Barroso, Cristina (Committee member) / Patrick, Donald (Committee member) / Barrett, The Honors College (Contributor) / School of Human Evolution and Social Change (Contributor)
Created2013-05
Description
It is presently believed that brown adipose tissue (BAT) is an important tissue in the control of obesity because it has the propensity to increase energy expenditure. The purpose of this study was to attempt to quantify the thermogenesis of BAT when four rats were exposed to a progression of low-fat to high-fat diet. Exogenous norepinephrine (NE) injections (dose of 0.25 mg/kg i.p.) were administered in order to elicit a temperature response, where increases in temperature indicate increased activity. Temperatures were measured via temperature sensing transponders that had been inserted at the following three sites: interscapular BAT (iBAT), the abdomen (core), and lower back (reference). Data showed increased BAT activity during acute (2-3 weeks) high fat diet (HFD) in comparison to low fat diet (LFD), but a moderate to marked decrease in BAT activity during chronic HFD (6-8 weeks) when compared to acute HFD. This suggests that while a HFD may initially stimulate BAT in the short-term, a long-term HFD diet may have negative effects on BAT activation.
ContributorsSivak, Hanna (Author) / Sweazea, Karen (Thesis director) / Herman, Richard (Committee member) / Caplan, Michael (Committee member) / School of Life Sciences (Contributor) / College of Integrative Sciences and Arts (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
Obesity is a rising problem in the country today, and countless efforts have been made to achieve long-term weight loss. Recent research indicates that through the manipulation of Brown Adipose Tissue (BAT) activity within the body, weight loss can be achieved. The goal of this experiment was to understand the effects of a high-fat diet (HFD) on BAT activity and diet-induced thermogenesis in cold-stressed rats. It was predicted that the HFD would stimulate BAT activity and this would then drive up thermogenic activity to promote weight loss. Diet-induced thermogenesis was predicted to increase during the HFD phase of this experiment as the body would require more energy to digest the more calorically dense food. Upon arrival at six weeks of age, the rats were started on a low-fat diet (LFD) ad libitum for three weeks. They were then transitioned into a HFD ad libitum for the next 8 weeks. Throughout the experiment, the rats were maintained in a cold-stressed environment at 22°C. It was determined that one of the rats was identified as obesity prone, while the other three rats were obesity resistant based on the rate of weight gain and caloric intake. Obesity can decrease metabolism in the body for many reasons, yet it was not seen in this experiment that the obesity prone rat demonstrated decreased metabolism in comparison to the others. Based on the differences seen in the reference temperatures and the BAT temperatures, it was determined that the BAT was active throughout both the LFD and HFD phases. However, the BAT did not rise significantly during the HFD period as expected. More research is indicated with a larger sample size to determine if BAT activity does continue to increase during a HFD as a result of diet-induced thermogenesis.
ContributorsLubold, Jessica Marie Sarah (Author) / Morse, Lisa (Thesis director) / Herman, Richard (Committee member) / School of Nutrition and Health Promotion (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
For the past couple decades, there has been a continuous rise in obesity and Type II Diabetes which has been attributed to the rise in calorically dense diets, especially those heavy in fats. Because of its rising prevalence, accompanied health concerns, and high healthcare costs, detection and therapies for these metabolic diseases are in high demand. Insulin resistance is a typical hallmark of Type II Diabetes and the metabolic deficiencies in obesity and is the main focus of this project. The primary purpose of this study is (1) detect the presence of two types of insulin resistance (peripheral and hepatic) as a function of age, (2) distinguish if diet impacted the presence of insulin resistance, and (3) determine both the short-term and long-term effects of caloric restriction on metabolic health. The following study longitudinally observed the changes in insulin resistance in high-fat fed and low-fat fed rodents under ad libitum and caloric restriction conditions over the course of 23 weeks. Fasting blood glucose, fasting insulin, body weight, and sensitivity of insulin on tissue were monitored in order to determine peripheral and hepatic insulin resistance. A high fat diet resulted in higher body weights and higher hepatic insulin resistance with no notable effect on peripheral insulin resistance. Caloric restriction was found to alleviate insulin resistance both during caloric restriction and four weeks after caloric restriction ended. Due to sample size, the generalizability of the findings in this study are limited. However, the current study did provide considerable results and can be viewed as a pilot study for a larger-scale study.
ContributorsZuo, Dana (Author) / Trumble, Benjamin (Thesis director) / Herman, Richard (Committee member) / Department of Psychology (Contributor) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
With the influence of the Western Diet, obesity has become a rising problem in the country today. Western Diet is characterized by the overconsumption of processed food that is low in nutritional values and high in saturated fats. Study showed that every two out of three adults in the United States are either overweight or obese. Being obese increase the risk of many other disease such as diabetes, cardiovascular disease and insulin resistance. Besides being a great health concern, obesity is also cause a great financial burden. Many efforts have been made to understand the defense against obesity and weight loss. The goal of this study was to understand the characterization of food intake and weight gain responses when imposed on a high-fat diet (HFD) using rats. It was predicted that weight gain would be dependent on energy intake and it would have a significant effect on adiposity compared to energy intake. Data showed that energy intake had high significance with adiposity whereas weight gain showed no significance. Also for the rats that were on HFD, the obesity-prone (OP) rats exhibited a great amount of weight gain and energy intake while the obesity-resistance (OR) rats showed a similar weight gain to the controlled group on low-fat diet (LFD) despite being hyperphagic. This suggests that OR is characterized by equal weight gain despite hyperphagia but this alone cannot explain the boy defense against obesity. More research is needed with a larger sample size to understand weight gain responses in order to fight against the epidemic of obesity.
ContributorsMao, Samuel (Author) / Herman, Richard (Thesis director) / Baluch, Page (Committee member) / Lamb, Timothy (Committee member) / WPC Graduate Programs (Contributor) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05