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- All Subjects: Obesity
- All Subjects: Weight loss
- Creators: Johnston, Carol
Description
ABSTRACT The hormone leptin is an important regulator of body weight and energy balance, while nitric oxide (NO) produced in the blood vessels is beneficial for preventing disease-induced impaired vasodilation and hypertension. Elevations in the free radical superoxide can result in impaired vasodilation through scavenging of NO. Omega 3 is a polyunsaturated fatty acid that is beneficial at reducing body weight and in lowering many cardiovascular risk factors like atherosclerosis. The present study was designed to examine the change in plasma concentrations of leptin, nitric oxide, and the antioxidant superoxide dismutase in addition to examining the association between leptin and NO in healthy normal weight adult female subjects before and following omega 3 intakes. Participants were randomly assigned to either a fish oil group (600 mg per day) or a control group (1000 mg of coconut oil per day) for 8 weeks. Results showed no significant difference in the percent change of leptin over the 8 week supplementation period for either group (15.3±31.9 for fish oil group, 7.83±27 for control group; p=0.763). The percent change in NO was similarly not significantly altered in either group (-1.97±22 decline in fish oil group, 11.8±53.9 in control group; p=0.960). Likewise, the percent change in superoxide dismutase for each group was not significant following 8 weeks of supplementation (fish oil group: 11.94±20.94; control group: 11.8±53.9; p=0.362). The Pearson correlation co-efficient comparing the percent change of both leptin and NO was r2= -0.251 demonstrating a mildly negative, albeit insignificant, relationship between these factors. Together, these findings suggest that daily supplementation with 600 mg omega 3 in healthy females is not beneficial for improving these cardiovascular risk markers. Future studies in this area should include male subjects as well as overweight subjects with larger doses of fish oil that are equivalent to three or more servings per week. The importance of gender cannot be underestimated since estrogen has protective effects in the vasculature of females that may have masked any further protective effects of the fish oil. In addition, overweight individuals are often leptin-resistant and develop impaired vasodilation resulting from superoxide-mediated scavenging of nitric oxide. Therefore, the reported antioxidant and weight loss properties of omega 3 supplementation may greatly benefit overweight individuals.
ContributorsAlanbagy, Samer (Author) / Sweazea, Karen (Thesis advisor) / Johnston, Carol (Committee member) / Shepard, Christina (Committee member) / Lespron, Christy (Committee member) / Arizona State University (Publisher)
Created2014
Description
Dietary counseling from a registered dietitian has been shown in previous studies to aid in weight loss for those receiving counseling. With the increasing use of smartphone diet/weight loss applications (app), this study sought to investigate if an iPhone diet app providing feedback from a registered dietitian improved weight loss and bio-markers of health. Twenty-four healthy adults who owned iPhones (BMI > 24 kg/m2) completed this trial. Participants were randomly assigned to one of three app groups: the MyDietitian app with daily feedback from a registered dietitian (n=7), the MyDietitian app without feedback (n=7), and the MyPlate feedback control app (n=10). Participants used their respective diet apps daily for 8-weeks while their weight loss, adherence to self-monitoring, blood bio-markers of health, and physical activity were monitored. All of the groups had a significant reduction in waist and hip circumference (p<0.001), a reduction in A1c (p=0.002), an increase in HDL cholesterol levels (p=0.012), and a reduction in calories consumed (p=0.022) over the duration of the trial. Adherence to diet monitoring via the apps did not differ between groups during the study. Body weight did not change during the study for any groups. However, when the participants were divided into low (<50% of days) or high adherence (>50% of days) groups, irrespective of study group, the high adherence group had a significant reduction in weight when compared to the low adherence group (p=0.046). These data suggest that diet apps may be useful tools for self-monitoring and even weight loss, but that the value appears to be the self-monitoring process and not the app specifically.
ContributorsThompson-Felty, Claudia (Author) / Johnston, Carol (Thesis advisor) / Wharton, Christopher (Christopher Mack), 1977- (Committee member) / Levinson, Simin (Committee member) / Arizona State University (Publisher)
Created2014
Description
Nut consumption, specifically almonds, have been shown to help maintain weight and influence disease risk factors in adult populations. Limited studies have been conducted examining the effect of a small dose of almonds on energy intake and body weight. The objective of this study was to determine the influence of pre-meal almond consumption on energy intake and weight in overweight and obese adults. In this study included 21, overweight or obese, participants who were considered healthy or had a controlled disease state. This 8-week parallel arm study, participants were randomized to consume an isocaloric amount of almonds, (1 oz) serving, or two (2 oz) cheese stick serving, 30 minutes before the dinner meal, 5 times per week. Anthropometric measurements including weight, waist circumference, and body fat percentage were recorded at baseline, week 1, 4, and 8. Measurement of energy intake was self-reported for two consecutive days at week 1, 4 and 8 using the ASA24 automated dietary program. The energy intake after 8 weeks of almond consumption was not significantly different when compared to the control group (p=0.965). In addition, body weight was not significantly reduced after 8 weeks of the almond intervention (p=0.562). Other parameters measured in this 8-week trial did not differ between the intervention and the control group. These data presented are underpowered and therefore inconclusive on the effects that 1 oz of almonds, in the diet, 5 per week has on energy intake and bodyweight.
ContributorsMcBride, Lindsey (Author) / Johnston, Carol (Thesis advisor) / Swan, Pamela (Committee member) / Mayol-Kreiser, Sandra (Committee member) / Arizona State University (Publisher)
Created2011
Description
Dietary self-monitoring has been shown to be a predictor of weight loss success and is a prevalent part of behavioral weight control programs. As more weight loss applications have become available on smartphones, this feasibility study investigated whether the use of a smartphone application, or a smartphone memo feature would improve dietary self-monitoring over the traditional paper-and-pencil method. The study also looked at whether the difference in methods would affect weight loss. Forty-seven adults (BMI 25 to 40 kg/m2) completed an 8-week study focused on tracking the difference in adherence to a self-monitoring protocol and subsequent weight loss. Participants owning iPhones (n=17) used the 'Lose It' application (AP) for diet and exercise tracking and were compared to smartphone participants who recorded dietary intake using a memo (ME) feature (n=15) on their phone and participants using the traditional paper-and-pencil (PA) method (n=15). There was no significant difference in completion rates between groups with an overall completion rate of 85.5%. The overall mean adherence to self-monitoring for the 8-week period was better in the AP group than the PA group (p = .024). No significant difference was found between the AP group and ME group (p = .148), or the ME group and the PA group (p = .457). Weight loss for the 8 week study was significant for all groups (p = .028). There was no significant difference in weight loss between groups. Number of days recorded regardless of group assignment showed a weak correlation to weight loss success (p = .068). Smartphone owners seeking to lose weight should be encouraged by the potential success associated with dietary tracking using a smartphone app as opposed to the traditional paper-and-pencil method.
ContributorsCunningham, Barbara (Author) / Wharton, Christopher (Christopher Mack), 1977- (Thesis advisor) / Johnston, Carol (Committee member) / Hall, Richard (Committee member) / Arizona State University (Publisher)
Created2012
Description
The purpose of this study was to gather qualitative data on different and novel methods used to self-monitor diet and exercise during a weight loss study. Participants who used either a traditional paper and pencil method or a smart phone weight loss app for diet and exercise tracking were recruited for focus groups. Focus group discussions centered on the liked and disliked aspects of recording, perceived behavior changes, and suggestions for improved self-monitoring. Focus groups were organized based on the method of self-monitoring. The app group tracked calorie intake and expenditure via the "Lose It" app on their smart phones. The paper & pencil group recorded exercise and food intake in a journal and self-regulated diet based on recommended servings from each food group (or exchange lists). Focus group sessions were audio-recorded, transcribed and coded by the researcher and an independent coder. Results indicated that app participants liked the convenience, affordability, and user-friendly features, but wanted more nutrition advice. App participants liked self-managing their diet, not restricting certain foods or food groups and allowing for indulgences by balancing calories and exercise. Also, they desired an accurate estimation of energy expenditure from an app, based on individual characteristics (i.e., gender and age). Participants who recorded on paper liked the size for a visual layout of food entries, but desired a technology-enhanced method with an auto-calculation of calorie intake and expenditure. They also suggested increased accountability and opportunities for social support would enhance self-monitoring. Overall, an ideal technology-assisted self-monitoring app or program would be free and include an auto-calculation of calorie intake, a gender- and age- specific estimation of calories expended, easy entry of foods from a large database, the ability to enter whole recipes, nutrition information and recommendations, and be available via phone, tablet or computer (based on personal preference).
ContributorsSterner, Danielle (Author) / Wharton, Christopher (Christopher Mack), 1977- (Thesis advisor) / Johnston, Carol (Committee member) / Hall, Richard (Committee member) / Arizona State University (Publisher)
Created2012
Description
Background: Obesity is considered one of the most serious public health issues worldwide. Small, feasible lifestyle changes are necessary to obtain and maintain weight loss. Clinical evidence is inconclusive about whether meal preloading is an example of a small change that could potentially increase the likelihood of weight loss and weight maintenance. Objective: The aim of this study is to determine if consuming 23 grams of peanuts, as a meal preload, before a carbohydrate-rich meal will lower post prandial glycemia and insulinemia and increase satiety in the 2 hour period after a carbohydrate-rich meal. Design: 15 healthy, non-diabetic adults without any known peanut or tree nut allergies were recruited from a campus community. A randomized, 3x3 block crossover design was used. The day prior to testing participants refrained from vigorous activity and consumed a standard dinner meal followed by a 10 hour fast. Participants reported to the test site in the fasted state to complete one of three treatment meals: control (CON), peanut (NUT), or grain bar (BAR) followed one hour later by a carbohydrate-rich meal. Satiety, glucose and insulin were measured at different time points throughout the visit. Each participant had a one-week washout period between visits. Results: Glucose curves varied between treatments (p=.023). Blood glucose was significantly higher one hour after ingestion of the grain bar compared to the peanut and control treatments (p<.001). At 30 minutes after the meal, the control glucose was significantly higher than for the peanut or grain bar (p=.048). Insulin did vary significantly between treatments (p<.001). The insulin change one hour after grain bar consumption was significantly higher than after the peanut or control at the same time point (p<.001). The change in insulin one hour after peanut consumption was significantly higher than for the control treatment (p=.002). Overall satiety, expressed as the 180 minute AUC, differed significantly between treatments (p=.001). One hour after preload consumption, peanut and bar consumption was associated with greater satiety than the water control (p<.001). At 30 minutes post-meal, the grain bar was associated with greater satiety versus the water control (p=.049). The bar was also associated with greater satiety versus peanut and control at 60 and 90 minutes post-meal (p=.003 and .034, respectively). At 120 minutes post-meal, the final satiety measurement, the bar was still associated with greater satiety than the peanut preload (p=.023). Total energy intake, including test meal, on treatment days did not differ significantly between treatment (p=.233). Conclusions: Overall satiety, blood glucose and blood insulin levels differed at different time points depending on treatment. Both meal preloads increased overall satiety. However, grain bar ingestion resulted in sustained satiety, greater than the peanut preload. Grain bar ingestion resulted in an immediate glycemic and insulinemic response. However, the response was not sustained after the test meal was ingested. The results of this study suggest that a low-energy, carbohydrate-rich meal preload may have a positive impact on weight maintenance and weight loss by initiating a sustained increase in overall satiety. More research is needed to confirm these findings.
ContributorsFleming, Katie R (Author) / Johnston, Carol (Thesis advisor) / Wharton, Christopher (Christopher Mack), 1977- (Committee member) / Shepard, Christina (Committee member) / Arizona State University (Publisher)
Created2012
Description
ABSTRACT This study evaluated the LoseIt Smart Phone app by Fit Now Inc. for nutritional quality among users during an 8 week behavioral modification weight loss protocol. All participants owned smart phones and were cluster randomized to either a control group using paper and pencil record keeping, a memo group using a memo function on their smart phones, or the LoseIt app group which was composed of the participants who owned iPhones. Thirty one participants completed the study protocol: 10 participants from the LoseIt app group, 10 participants from the memo group, and 11 participants from the paper and pencil group. Food records were analyzed using Food Processor by ESHA and the nutritional quality was scored using the Healthy Eating Index - 2005 (HEI-2005). Scores were compared using One-Way ANOVA with no significant changes in any category across all groups. Non-parametric statistics were then used to determine changes between combined memo and paper and pencil groups and the LoseIt app group as the memo and paper and pencil group received live counseling at biweekly intervals and the LoseIt group did not. No significant difference was found in HEI scores across all categories, however a trend was noted for total HEI score with higher scores among the memo and paper and pencil group participants p=0.091. Conclusion, no significant difference was detected between users of the smart phone app LoseIt and memo and paper and pencil groups. More research is needed to determine the impact of in-person counseling versus user feedback provided with the LoseIt smart phone app.
ContributorsCowan, David Kevin (Author) / Johnston, Carol (Thesis advisor) / Wharton, Christopher (Christopher Mack), 1977- (Committee member) / Mayol-Kreiser, Sandra (Committee member) / Arizona State University (Publisher)
Created2011
Description
ABSTRACT
Objective: This research examined the effectiveness of a weight loss diet incorporating high protein pasta and breakfast cereal products as compared to a weight loss diet using conventional versions of gluten-free pasta and breakfast cereal.
Design: In a 6-week parallel-arm food trial (representing the first phase of a 12-week cross-over trial), 26 overweight and obese (Mean BMI 43.1 ± 12.4 kg/m²) participants, free of related comorbidities, were randomly assigned to the Zone diet (~29% energy intake from protein) or a control diet (~9% energy from protein). Participants were included in the trial if they satisfied the criteria for elevated risk for metabolic syndrome (top half of the TG/HDL ratios of all who were tested). Participants were instructed to eat prepared meals (total of 7 cereal packets and 14 pasta meals weekly) that included patented food technologies for the Zone diet and commercially available gluten-free rice pasta and a conventional name brand boxed cereal for the control diet. Body composition was measured with a bioelectrical impedance scale at weeks 1, and 6. Food records and diet adherence were recorded daily by the participants.
Results: Both the Zone and control diets resulted in significant weight loss (-2.9 ± 3.1 kg vs. -2.7 ± 2.6 kg respectively) over time (p = 0.03) but not between groups (p = 0.96). Although not statistically significant, the Zone diet appears to have influenced more weight loss at trial weeks 3, 4, and 5 (p = 0.46) than the control diet. The change in FFM was significant (p = 0.02) between the Zone and control groups (1.4 ± 3.6 kg vs. -0.6 ± 1.5 kg respectively) at week-6. Study adherence did not differ significantly between diet groups (p = 0.53).
Conclusions: Energy-restricted diets are effective for short-term weight loss and high protein intake appears to promote protein sparing and preservation of FFM during weight loss. The macronutrient profile of the diet does not appear to influence calorie intake, but it does appear to influence the quality of weight loss. Other measures of body composition and overall health outcomes should be examined by future studies to appropriately identify the potential health effects between these diet types.
Objective: This research examined the effectiveness of a weight loss diet incorporating high protein pasta and breakfast cereal products as compared to a weight loss diet using conventional versions of gluten-free pasta and breakfast cereal.
Design: In a 6-week parallel-arm food trial (representing the first phase of a 12-week cross-over trial), 26 overweight and obese (Mean BMI 43.1 ± 12.4 kg/m²) participants, free of related comorbidities, were randomly assigned to the Zone diet (~29% energy intake from protein) or a control diet (~9% energy from protein). Participants were included in the trial if they satisfied the criteria for elevated risk for metabolic syndrome (top half of the TG/HDL ratios of all who were tested). Participants were instructed to eat prepared meals (total of 7 cereal packets and 14 pasta meals weekly) that included patented food technologies for the Zone diet and commercially available gluten-free rice pasta and a conventional name brand boxed cereal for the control diet. Body composition was measured with a bioelectrical impedance scale at weeks 1, and 6. Food records and diet adherence were recorded daily by the participants.
Results: Both the Zone and control diets resulted in significant weight loss (-2.9 ± 3.1 kg vs. -2.7 ± 2.6 kg respectively) over time (p = 0.03) but not between groups (p = 0.96). Although not statistically significant, the Zone diet appears to have influenced more weight loss at trial weeks 3, 4, and 5 (p = 0.46) than the control diet. The change in FFM was significant (p = 0.02) between the Zone and control groups (1.4 ± 3.6 kg vs. -0.6 ± 1.5 kg respectively) at week-6. Study adherence did not differ significantly between diet groups (p = 0.53).
Conclusions: Energy-restricted diets are effective for short-term weight loss and high protein intake appears to promote protein sparing and preservation of FFM during weight loss. The macronutrient profile of the diet does not appear to influence calorie intake, but it does appear to influence the quality of weight loss. Other measures of body composition and overall health outcomes should be examined by future studies to appropriately identify the potential health effects between these diet types.
ContributorsJames, Andrew (Author) / Johnston, Carol (Thesis advisor) / Mayol-Kreiser, Sandra (Committee member) / Shepard, Christina (Committee member) / Arizona State University (Publisher)
Created2015
Description
Multiple health-related benefits have been associated with adherence to plant-based diets, including vegan, vegetarian, and pescatarian dietary patterns. Despite a consistent body of evidence on the importance of healthy diets, Americans continue to find difficulty in establishing and adhering to dietary goals that could elicit long-term health benefits. Recent research suggests an important role for goal-setting strategies in health behavior change attempts, with some success shown in dietary behavior change, specifically. The current study thus aimed to explore whether having multiple goals alongside one primary goal of following a vegetarian, vegan, or pescatarian diet would increase the achievability of that goal. Participants of this study were broken into two groups: currently following a plant-based diet (ADHERE) and striving to follow a plant-based diet (STRIVE). Researchers hypothesized that the number of health and/or diet related alternative goals set by participants would differ between the two groups, that the ADHERE group would report that their alternative goals were more helpful and less interfering in achieving their dietary goal than the STRIVE group, and that a higher rank of importance of the dietary goal would predict being in the ADHERE group. Results showed that the number of health and/or diet related alternative goals did not differ between groups. The ADHERE group and STRIVE group did not have significantly different helpfulness and interference reports. Although, in an exploratory analysis, it was shown that those participants who reported at least 2 health/diet related alternative goals found those goals to be significantly more helpful than those who reported 0 or 1 health/diet goal. Results showed that rank of dietary goal did not predict group assignment. Overall, the results from this study showed that the type of alternative goal was very important when pursuit of multiple goals was in effect. Type of alternative goal seemed to be a higher predictor of the perceived helpfulness of the alternative goals than previous achievement of goals.
ContributorsShilling, Katy (Author) / Wharton, Christopher (Christopher Mack), 1977- (Thesis advisor) / Karoly, Paul (Committee member) / Johnston, Carol (Committee member) / Arizona State University (Publisher)
Created2018
Description
Objectives: To investigate the potential of vinegar supplementation as a means for reducing visceral fat in healthy overweight and obese adults, and to evaluate its effects on fasting blood glucose and fasting insulin.
Subjects and Methods: Forty-five sedentary overweight and obese adult participants with a waist circumference greater than 32 inches for women and 37 inches for men were randomly assigned to one of two groups, the vinegar group (VIN, n=21) or the control group (CON, n=24), and instructed to consume either two tablespoons of liquid red wine vinegar (3.6g acetic acid) or a control pill (0.0225g acetic acid) twice daily at the beginning of a meal for 8 weeks. Participants were also instructed to maintain normal diet and physical activity levels. Anthropometric measures, dual-energy x-ray absorptiometry (DXA) scans, blood samples, and 24-hour dietary recalls were collected at baseline and at end of trial. A compliance calendar was provided for daily tracking of vinegar supplementation.
Results: Compliance to vinegar supplementation averaged 92.7 ±13.3% among the VIN group and 89.1 ±18.9% among the CON group. There were no statistically significant differences in anthropometric measurements between baseline and week 8: weight (P=0.694), BMI (P=0.879), and waist circumference (P=0.871). Similarly, DXA scan data did not show significant changes in visceral fat (P=0.339) or total fat (P=0.294) between baseline and week 8. The VIN group had significant reductions in fasting glucose (P=0.003), fasting insulin (P <0.001), and homeostatic model assessment of insulin resistance scores (P <0.001) after treatment.
Conclusions: These data do not support the findings from previous studies that indicated a link between vinegar supplementation and increased fat metabolism, specifically visceral fat reduction.
Subjects and Methods: Forty-five sedentary overweight and obese adult participants with a waist circumference greater than 32 inches for women and 37 inches for men were randomly assigned to one of two groups, the vinegar group (VIN, n=21) or the control group (CON, n=24), and instructed to consume either two tablespoons of liquid red wine vinegar (3.6g acetic acid) or a control pill (0.0225g acetic acid) twice daily at the beginning of a meal for 8 weeks. Participants were also instructed to maintain normal diet and physical activity levels. Anthropometric measures, dual-energy x-ray absorptiometry (DXA) scans, blood samples, and 24-hour dietary recalls were collected at baseline and at end of trial. A compliance calendar was provided for daily tracking of vinegar supplementation.
Results: Compliance to vinegar supplementation averaged 92.7 ±13.3% among the VIN group and 89.1 ±18.9% among the CON group. There were no statistically significant differences in anthropometric measurements between baseline and week 8: weight (P=0.694), BMI (P=0.879), and waist circumference (P=0.871). Similarly, DXA scan data did not show significant changes in visceral fat (P=0.339) or total fat (P=0.294) between baseline and week 8. The VIN group had significant reductions in fasting glucose (P=0.003), fasting insulin (P <0.001), and homeostatic model assessment of insulin resistance scores (P <0.001) after treatment.
Conclusions: These data do not support the findings from previous studies that indicated a link between vinegar supplementation and increased fat metabolism, specifically visceral fat reduction.
ContributorsGonzalez, Lisa Ann (Author) / Johnston, Carol (Thesis advisor) / Mayol-Kreiser, Sandra (Committee member) / McCoy, Maureen (Committee member) / Arizona State University (Publisher)
Created2019