No / Bariatric surgery has emerged as an increasingly popular weight loss intervention, with larger and more endurable weight loss compared to pharmacological and behavioural interventions. The degree of weight loss patients experience varies, between individuals, surgeries and over time. An explanation as to why differing weight loss trajectories exist post-surgery could be due to the complex interplay of individual differences in relation to eating behaviours and appetite. Thus the aim of this narrative review is to explore literature between 2008 and 2018, to assess the impact of impact of bariatric surgery on food selection and nutrient status, on eating behaviour traits and on disturbed and disordered eating behaviour, to determine their impact of weight loss success and weight loss trajectories. Immediately post-surgery, up until 1–2 years post-surgery, there is a reliance upon the surgery's alteration of the gastrointestinal tract to control food intake and subsequently lose weight. Energy intake is reduced, dietary adherence is higher, supplement intake is higher, appetite ratings are lower, there is a reduction in psychopathology, and an increase in wellbeing. After this point, patients become more susceptible to weight regain, as this is the point where passive observation of the weight reducing action of surgery, moves into more cognitive effort, on the part of the individual, to control energy intake. There are various factors which influence an individual's ability to successfully regulate their energy intake post-surgery, such as their level of Disinhibition, Restraint, Hunger, Emotional Eating, Uncontrolled Eating, psychopathology and wellbeing. The need for continued psychological and nutritional support post-surgery is necessary to reduce weight regain susceptibility.

A series of three experiments were conducted to evaluate different methods of estimating forage mass of tall fescue pastures, and dry matter intake and digestibility in beef steers under indoor and grazing conditions. Forage mass was estimated with the herbage cutting method (HCM) and three indirect methods; the pasture capacitance meter (PCM), the plate meter (PPM), and the visual estimation (VE). The coefficients of determination from the calibration equations were 0.686, 0.751, and 0.862 for the PCM, PPM, and VE, respectively. There were differences in forage mass estimates due to sampling method, sampling date, and their interaction. The second experiment was a digestion trial conducted with confined animals to determine the recovery rate of chromic oxide and alkanes from controlled release capsules and to evaluate the accuracy of the concurrent estimations of intake and digestibility. No difference was found in the recovery rate of either alkanes or chromic oxide during the 7 d of the collection period. Likewise, actual fecal output, dry matter intake, and digestibility were not different from the estimated values. However, estimated values had to be adjusted for the respective recovery rate. The third experiment was conducted under grazing conditions to evaluate the chromic oxide controlled release capsule technique in estimating intake and digestibilty. In this trial, although the recovery rate of the marker was extremely high (avg. = 1.89), the actual and estimated values of dry matter fecal output, intake, and digestibility were not different. Again the recovery rate had to be used as a correction factor. / Ph. D.

Type 2 diabetes (T2D) is one of the fasting growing chronic diseases, caused by insulin resistance and pancreatic β-cell dysfunction. While over thirty medications were approved to treat T2D in the United States, less than one in four patients treated with anti-diabetic drugs achieved the glycemic target. Thus, identifying more effective anti-diabetic drugs is still needed for improving glycemic control in T2D patients. Incretins are gut hormones that possess potent insulinotropic action, which have drawn considerable attention in research and developing treatment strategy for T2D. Specifically, glucagon like peptide 1 (GLP-1), the most important incretin that is secreted from enteroendocrine L-cells in response to food ingestion, plays a vital role in maintaining glycemic homeostasis via potentiating glucose stimulated insulin secretion (GSIS) and promoting pancreatic β-cell proliferation and survival. Therefore, targeting L-cells to induce GLP-1 secretion would be an alternative strategy for treating T2D. The goal of this research was to identify low-cost and safe naturally occurring agents as a primary or adjuvant treatment for T2D. Here, I found that a small molecule, elenolic acid (EA), which was generated in our lab but is also present in mature olive and extra virgin olive oil, dose-dependently stimulated GLP-1 secretion in mouse clonal L-cells and isolated mouse ileum crypts. EA induced a rapid increase in intracellular [Ca2+]i and the production of inositol trisphosphate in L-cells, indicating that EA activates phospholipase C (PLC)-mediated signaling. Consistently, inhibition of (PLC) ablated EA-stimulated increase of [Ca2+]i and GLP-1 secretion in L-cells. In addition, EA-triggered GLP-1 secretion from L-cells was blocked by YM-254890, a Gαq inhibitor. Consistent with our in vitro study, a single dose of EA acutely stimulated GLP-1 secretion in mice, accompanied with an improved oral glucose tolerance. Chronic administration of EA restored the impaired glucose and lipid homeostasis in DIO mice, which may be partially due to promoting GLP-1 secretion and reduced hepatic gluconeogenesis. In addition, EA suppressed appetite, reduced food intake and gastric emptying rate, as well as promoted weight loss in obese mice, demonstrating that it is also an anti-obesity agent. Further, EA treatment reduced lipid absorption, and promoted hepatic fatty acid oxidation, and reversed abnormal plasma lipid profiles in DIO mice. Consistently, EA exerted potent anti-diabetic action in db/db mice, and its blood glucose-lowering effect is comparable with that of liraglutide in blood glycemic control but is better than that of metformin in this overt diabetic model. Collectively, I have identified for the first time, as to the best of our knowledge, that EA could be a dual-action compound that exerts anti-diabetic effects via activation of the GLP-1 mediated metabolic pathway and suppression of hepatic gluconeogenesis, leading to effective control on food intake, body weight gain, and glycemia in T2D mice. / Doctor of Philosophy / Type 2 diabetes (T2D) is one of the fasting growing chronic diseases, which results from insulin resistance and pancreatic β-cell dysfunction. Even though there have been over thirty drugs approved to treat T2D in the United States, less than 25% of patients treated with anti-diabetic drugs achieved the glycemic target. Thus, more effective anti-diabetic drugs are still needed for improving glycemic control in patients with T2D. Incretins are a group of gut hormones and responsible for over 50% postprandial insulin secretion in humans, which have drawn considerable attention in research and developing a treatment strategy for T2D. Specifically, glucagon-like peptide 1 (GLP-1), the most important incretin that is secreted from enteroendocrine L-cells in response to food ingestion, plays a vital role in controlling blood glucose via potentiating glucose-stimulated insulin secretion (GSIS) and promoting pancreatic β-cell proliferation and survival. Therefore, targeting L-cells to induce GLP-1 secretion would be an alternative strategy for treating T2D. The goal of this research was to identify low-cost and safe naturally occurring agents as a primary or adjuvant treatment for T2D. Here, I found that a small molecule, elenolic acid (EA), which was synthesized in our lab but is also present in mature olive and extra virgin olive oil, dose-dependently stimulated GLP-1 secretion in mouse clonal L-cells and isolated mouse ileum crypts (containing L-cells). Further experiments showed that EA induced a rapid increase in intracellular [Ca2+]i and the production of inositol trisphosphate (IP3) in L-cells, indicating that EA activates phospholipase C (PLC)-mediated signaling, as IP3 is a direct product of PLC. Consistently, inhibition of PLC ablated EA-stimulated increase of [Ca2+]i and GLP-1 secretion in L-cells. In addition, EA-triggered GLP-1 secretion from L-cells was blocked by YM-254890, a Gαq inhibitor. In line with the in vitro study, a single dose of EA acutely elevated plasma GLP-1 concentration in mice, accompanied by improved oral glucose tolerance. Chronic administration of EA restored the impaired glucose and lipid homeostasis in diet-induced obese (DIO) mice, which may be partially due to promoting GLP-1 secretion and reduced hepatic gluconeogenesis. In addition, EA suppressed appetite, reduced food intake, and gastric emptying rate, as well as promoted weight loss in the DIO mice, demonstrating that it is also an anti-obesity agent. Further, EA treatment reduced lipid absorption and promoted hepatic fatty acid oxidation, as well as reversed abnormal plasma lipid profiles in the DIO mice. Consistently, EA exerted potent anti-diabetic action in predisposed diabetic mice (db/db), and its blood glucose-lowering effect is comparable with that of liraglutide, a commercial GLP-1 receptor agonist, in blood glycemic control but is better than that of metformin, a widely used first-line anti-diabetic drug, in this overt diabetic model. Collectively, I have identified for the first time, as to the best of our knowledge, that EA could be a dual-action compound that exerts anti-diabetic effects via activation of the GLP-1 mediated metabolic pathway and suppression of hepatic gluconeogenesis, leading to effective control on food intake, body weight gain, and glycemia in T2D mice.

The population of older adults continues to grow in the US, as does the prevalence of overweight and obesity within this group. Several factors may contribute to age-related weight gain, such as a reduced energy expenditure and energy intake requirements, and a susceptibility to energy over-consumption. Serious consequences result from overweight and obesity, such as increased risk of chronic disease, decreased quality of life and increased healthcare costs. Thus, effective weight management strategies are needed which target this population. Reducing energy-containing beverage intake and increasing water intake are often suggested as strategies for weight loss, yet surprisingly little data exists to support the effectiveness of these strategies. Previous studies have shown that older adults consume fewer calories at a laboratory test meal following a water preload, but it is unknown whether this reduced energy intake can be sustained over time to produce weight loss. Epidemiological studies using self-reported dietary intake have shown that substituting water for energy-containing beverages decreases total energy intake, and that drinking > 1L of water is associated with greater weight loss in overweight women compared to overweight women who consumed < 1L daily. However, these studies were a secondary analysis of a trial comparing multiple weight loss strategies and increasing water consumption was not a primary outcome of interest. To directly address this issue, we hypothesized that increased water consumption would increase weight loss in healthy overweight and obese older adults in combination with a 12-week hypocaloric diet as compared to a hypocaloric diet alone. As hypothesized, older adults randomized to the increased water intake group demonstrated greater weight loss than those randomized to the diet alone group (7.4 kg vs. 5.5 kg, respectively). Because energy-containing beverages contribute to total energy intake without a concomitant reduction in food intake, substituting water or energy-free beverages for energy-containing beverages appears to be an effective weight management strategy for older adults. / Ph. D.

Previous research on grazing behavior has shown that ruminants will select a mixed diet. The use of adjacent monocultures is an essential tool for determining dietary preference of forages. Much of the work to date has been conducted with white clover (Trifolium repens L.) and perennial ryegrass (Lolium perenne L.). Partial preference for white clover over ryegrass has been reported consistently and partial preference for legumes is thought to occur regardless of the legume and grass species being evaluated. Two forage species, tall fescue (Festuca arundinacea Schreb. or Lolium arundinaceum (Schreb.) S.J. Darbyshire) and alfalfa (Medicago sativa subsp. sativa L.), which had not been evaluated together previously as adjacent monocultures were grazed by beef steers in the present set of experiments. Steers exhibited a partial preference for alfalfa of 61 to 65% when given a choice of grazing alfalfa or tall fescue as adjacent monocultures, regardless of the ground area proportion of the two forages offered. Steers grazing tall fescue monocultures spent more time ruminating (P = 0.02) and tended to graze less time (P = 0.06) than steers in adjacent monoculture treatments. Time spent idling, number of prehensions and mastications, and bite rate were similar (P > 0.05) among treatments. Steers grazing tall fescue monocultures spent less time standing, more time lying, were less active and took fewer steps (P ≤ 0.05) than steers in adjacent monoculture treatments. Grazing behavior was examined when alfalfa had not been in the previous diet of the steers. Cattle without previous experience grazing alfalfa spent 78% of the time grazing alfalfa, whereas after having experience grazing it they spent a lower (P = 0.04) proportion of their time grazing alfalfa (72%). Overall proportion of the day spent grazing both forages was lower (P = 0.0001) when alfalfa was novel (40%), compared to when steers were experienced grazing both forages (46%). Proportion of the day spent idling was greater (P < 0.0001) when alfalfa was novel (35%), compared to when both forages were familiar to the steers (26%). Previous research has reported that ruminants exhibit a diurnal pattern of preference by decreasing the proportion of white clover consumed from morning to late afternoon while increasing the proportion of perennial ryegrass in the diet. This is thought to be a strategy to increase fiber intake before nightfall or as a response to higher carbohydrate levels in grass in the afternoon. In the present study, proportion of grazing time in alfalfa was higher (P = 0.02) in the afternoon (76.8 %) than in the morning (72.1 %). While fiber concentration was higher in the tall fescue, carbohydrate concentrations were similar. Steers were not attempting to increase fiber intake in the afternoon in the present study. Dry matter intake of steers grazing adjacent monocultures of alfalfa and tall fescue was estimated with n-alkanes. Diet composition was estimated using n-alkanes and long chain alcohols (LCOH) in several different combinations. The use of LCOH added additional characterization of the forages, but diet composition estimates were not different (P ≥ 0.22) than when estimated using four different n-alkanes. Laboratory analysis costs may be reduced if n-alkanes alone can adequately characterize the forages being consumed, depending on the forage species in question. Meteorological conditions impacted DMI with intake being less in hotter conditions. Steers had similar partial preferences for alfalfa over tall fescue (P = 0.13, 79% and 70% alfalfa in yr 1 and 2, respectively) even though total DMI differed between years (P = 0.002, 9.4 kg d-1 and 4.5 kg d-1 in yr 1 and 2, respectively). Lower DMI in yr 2 was attributed to hotter air temperatures. When animals are consuming two different forages as adjacent monocultures such as in the current experiments, it is important to determine the proportion of each forage in the diet before calculating DMI using odd chain n-alkanes of the forage along with a dose even chained n-alkane. Dry matter intake can be overestimated if the proportion of the forages consumed is not estimated and accounted for in the equation. This would apply to other studies utilizing mixed swards or any diet containing multiple components that differ in concentration of the n-alkane being used for DMI estimation. Analysis of n-alkane concentration should be performed on each item in the diet and the proportion of each item in the diet estimated so that the right value can be used in the calculation. Differences in marker concentrations between years also indicate the importance of analyzing those concentrations in the feed or forage at the time of fecal collection and not using values reported from previous research. / Ph. D.

Background and Purpose: Little is known about influences of obstructive sleep apnea syndrome (OSAS) on dietary intake and body composition. The purpose of this study was to evaluate dietary status, body fat distribution and leptin in overweight young men with and without OSAS in comparison to published values for normal weight counterparts. Methods: Groups were comprised of 24 sedentary overweight young men with and without OSAS, who had a body mass index (BMI) greater than 25 kg/m². Serum leptin concentration was measured in the 24 subjects using radioimmunoassay, while OSAS assessment was done using nighttime home somnography. Analysis of 4-day diet recalls was performed using Nutritionist Pro (First DataBank, Inc., San Bruno, CA). A Healthy Eating Index (HEI) score was calculated for the 24 overweight subjects. Results: There were no differences between the two overweight groups for total fat mass, central abdominal fat, BMI, waist circumference, leptin, or the HEI. The HEI was not predictive of overall OSAS severity; however, BMI was moderately related to OSAS severity (r = 0.39; p=0.05). The normal weight group did have a 50% higher report of carbohydrate intake, and consumed on average, 500 more kilocalories per day. The normal weight group consumed 50% less sodium, and 50% more Vitamin's C and E including a 13% increase in the HEI. Conclusions: Regulation of eating behavior and related influences on diet composition may be affected by a number of neurohormonal disturbances associated with OSAS and/or obesity, itself. Further research is needed to quantify these possible differences on dietary status and the underlying mechanism involved. / Master of Science

Prediabetes is associated with an elevated risk for developing type 2 diabetes (T2DM) and associated cardiovascular complications. Lifestyle factors such as physical activity (PA) and dietary intake are strongly implicated in the development of metabolic disease, yet few Americans meet PA and dietary recommendations. Middle-aged and older adults are at increased risk for developing prediabetes and T2DM due to age-related muscle loss, increased fat mass, and alterations in glucose handling. In addition, this segment of the population is least likely to meet PA guidelines, particularly the resistance training (RT) recommendation of completing a whole body routine 2x/week. Ideally, individuals would alter their lifestyle in order to meet PA guidelines and habitually consume a healthy diet, to decrease disease risk. However, behavior change is difficult and optimal strategies to promote and maintain changes have yet to be determined. Furthermore, behavior change interventions tend to be time-, cost-, and resource-intensive, limiting the ability for efficacious programs to be translated into community settings and broadly disseminated. Evidence suggests that health-related behaviors, particularly diet and exercise habits, tend to cluster together. Thus, intervening on one behavior (e.g. PA) may elicit a spillover effect, promoting alterations in other behaviors (e.g. diet), though findings to date are conflicting. The purpose of this dissertation was to determine if participation in a social cognitive theory-based RT program targeting the initiation and maintenance of RT exerts a spillover effect and is associated with alterations in dietary intake and/or non-RT PA in a population at risk for T2DM. Data from the 15-month Resist Diabetes study was analyzed to evaluate this possibility. Sedentary, overweight/obese (BMI 25-39.9 kg/m2 ), middle-aged and older (50 -69 years) adults with prediabetes (impaired fasting glucose and/or impaired glucose tolerance) completed a 3 month initiation phase where they RT 2x/week in a lab-gym with an ACSM-certified personal trainer. Participants then completed a 6-month faded contact maintenance phase, and a 6-month no-contact phase during which they were to continue RT on their own in a public facility. No advice or encouragement was given to participants to alter dietary intake or non-RT PA habits. At baseline, and months 3, 9, and 15, three non-consecutive 24-hour diet recalls were collected to evaluate dietary intake and quality, the Aerobics Institute Longitudinal Study Questionnaire was completed to evaluate non-RT PA, and body mass, body composition, and strength (3 repetition maximum on leg and chest press) were measured. At months 3, 9, and 15 social cognitive theory (SCT) constructs were assessed with a RT Health Beliefs Questionnaire. In the first study, dietary intake was assessed at baseline and after 3 months of RT. Using paired sample t-tests, reductions in intake of energy (1914 ± 40 kcal vs. 1834 ± 427 kcal, p = 0.010), carbohydrate (211.6 ± 4.9 g vs. 201.7 ± 5.2 g, p = 0.015), total sugar (87.4 ± 2.7 g vs. 81.5 ± 3.1 g, p = 0.030), glycemic load (113.4 ± 3.0 vs. 108.1 ±3.2, p= 0.031), fruits and vegetables (4.6±0.2 servings vs. 4.1±0.2 servings, p= 0.018), and sweets and desserts (1.1 ± 0.07 servings vs. 0.89 ± 0.07 servings, p = 0.023) were detected from baseline to month 3. No changes in other dietary intake variables were observed. These findings supported additional investigation in this area. The second study assessed changes in overall diet quality (Healthy Eating Index [HEI]-2010 scores) and non-RT PA over the initiation, maintenance, and no-contact phases using mixed effects models. Demographic, physiological, and psychosocial factors that may predict alterations to diet quality and non-RT PA were also explored. Energy and carbohydrate intake decreased with RT (β= -87.9, p=.015 and β= -16.3, p<.001, respectively). No change in overall dietary quality (HEI-2010 score: β= -0.13, p=.722) occurred, but alterations in HEI-2010 sub-scores were detected. Maintenance of RT was accompanied by an increase in MET-min/week of total non-RT PA (β=153.5, p=0.01), which was predicted by increased self-regulation for RT (β=78.1, p=0.03). RT may be a gateway behavior leading to improvements in other health-related behaviors among adults with prediabetes. These results support the use of singlecomponent vs. multi-component interventions. This may have broad translational potential for the development of time-, resource-, and cost-efficient lifestyle interventions which can improve multiple health-related behaviors and decrease disease risk. / Ph. D.

The accurate measurement of total energy expenditure is a cornerstone of metabolic research. However, there is a lack of measurement methods that are valid, objective, inexpensive, and easy to use. Accelerometry, along with validated prediction equations for resting energy requirements, may provide an opportunity to fill this void. Twenty weight stable adults (12 female, 8 male) who recently participated in a controlled feeding study comprised the study sample. Total energy requirements were assessed from the controlled feeding period in which weight stability was achieved using the intake-balance method. Resting energy expenditure was assessed using the Mifflin-St. Jeor equation. Participants wore accelerometers to objectively assess habitual physical activity. The accelerometer data obtained along with subjects' demographic and biometric data were used to predict non-resting energy expenditure (NREE) using step-wise linear regression in JMP. Bland-Altman plots and Spearman's Rho correlations were used to determine the validity of the total energy requirements obtained from the sum of the predicted non-resting energy expenditure. Estimated resting energy expenditure was compared with the total energy requirements assessed using the intake-balance method from the controlled feeding period. The resulting prediction equation is as follows: 480.93 – 180.69(sex) + 0.21(Accelerometer kcals) + 617.98(BF%) = AEE. The sex was coded as 1 for females and 0 for males. This prediction model has a coefficient of determination of 0.74 (0.70 adjusted). On average, the model overestimates AEE by 76 kcals. This new model could be the key to accurately, inexpensively and objectively measuring total energy requirements. / Master of Science / Accurate measurement of the total amount of energy (i.e. calories) utilized by the body throughout the day, also known as total energy expenditure, is a vital component of metabolic research. However, there is a lack of measurement methods that are valid, objective, inexpensive, and easy to use. Accelerometers combined with equations designed to predict total energy expenditure may be able to fill this gap. Accelerometers are devices worn on the body that measure accelerative forces from physical activity. Twenty weight stable adults (12 female, 8 male), who recently participated in a study in which all dietary intake and exercise were closely monitored (controlled feeding study), comprised the study sample. The amount of energy needed to maintain weight (total energy requirements) was assessed from the controlled feeding period in which weight stability was achieved. Resting energy expenditure, the energy burned while the body is at rest, was assessed using an equation often used to estimate energy expenditure, the Mifflin-St. Jeor equation. Participants wore accelerometers to objectively assess habitual physical activity. The accelerometer data obtained along with subjects’ demographic (age, sex) and biometric (height, weight, BMI, etc.) data were used to predict non-resting energy expenditure (resting energy expenditure subtracted from total energy expenditure). Multiple statistical tests were used to determine the validity of the total energy requirements obtained from the sum of the predicted non-resting energy expenditure (NREE) and resting energy expenditure. Estimated resting energy expenditure was compared with the total energy requirements assessed using the intake-balance method from the controlled feeding period. The resulting prediction equation is as follows: 480.93 – 180.69(sex) + 0.21(Accelerometer kcals) + 617.98(BF%) = NREE. The sex was coded as 1 for females and 0 for males. This prediction model has a coefficient of determination of 0.74 (0.70 adjusted), which means 70% of the variation in non-resting energy expenditure was explained by changes in the variables in the equation. On average, the model overestimates NREE by 76 Calories per day. This new model could be the key to accurately, inexpensively and objectively measuring total energy requirements.

Controversy surrounds the use of artificial sweeteners (non-nutritive sweeteners [NNS]) as an effective weight-loss and/or maintenance strategy. This controversy is especially important as obesity is an epidemic in the United States. Excessive added sugar intake, primarily from sugar-sweetened beverages, has been linked to increased risk of overweight and obesity, as well as type 2 diabetes and cardiovascular disease. NNS provide minimal to no calories and thus, they have been suggested as a method to reduce added sugar intake, and consequently decrease energy intake, weight, and cardiometabolic risk. However, NNS intake has been associated with various health outcomes in observational studies and randomized controlled trials, including cancer, weight gain and loss, physiological and intestinal changes, cardiovascular disease, and diabetes. The uncertainties around the effect of NNS on health outcomes stem from a variety of limitations, one of which is inadequate dietary assessment methodology. Accuracy of dietary intake assessment methods is limited by the inability to distinguish between different types of NNS and lack of information about consumer use of NNS in a variety of beverages and foods. The purpose of this investigation is to explore NNS consumer characteristics and to characterize NNS intake in a sample of rural Southwest Virginian adults. This characterization is especially important for rural populations, as they are known to be high sugar-sweetened beverage consumers and are at an increased risk of obesity and chronic disease; thus, NNS could serve as a replacement method to facilitate cardiometabolic health. Cross-sectional data from a large randomized controlled trial, Talking Health (n=301), was utilized in this investigation to compare demographic characteristics, anthropometrics, biochemical markers, dietary quality, and dietary factors between NNS consumers and NNS non-consumers. This data was also used to characterize NNS intake (frequency, type, and source of sweetener). Of this rural sample, 33% consumed NNS, with sucralose being the most prevalent type of NNS and diet soda being the most frequently consumed source of NNS. NNS consumers had a higher BMI status than NNS non-consumers. However, NNS consumers had better overall dietary quality than NNS non-consumers. The characteristics of these NNS consumers and their intake patterns can be used to develop well-designed dietary intake assessment tools that accurately measure NNS intake, which can facilitate a better understanding of the associations of NNS with health outcomes. / Master of Science

Seventy-six percent of men and 71% of women over the age of 55 in the United States are considered overweight or obese,1 and the numbers are expected to rise2 especially since the population is aging.3 Aside from various metabolic comorbidities, such as hypertension, dyslipidemia, and coronary artery disease,4 overweight and obesity are also linked to decreased mobility5 and increased rate of falls in elderly,6 all of which may lead to premature death. Furthermore, adults over the age of 65 have 339% greater obesity-related medical expenses compared to younger adults (18-30 years old),7 thus strategies to promote weight management are needed. Belonging to the group of fiber, prebiotics are selectively fermented non-digestible food ingredients that have a favorable impact on the composition and activity of the gut microbiota. Specifically, inulin-type fructans (ITF) including inulin, oligosaccharides, and fructooligosaccharides have been generating interest in the prebiotic area in the past two decades. A lot of attention has been directed at weight management, since ITFs are known to stimulate the excretion of anorectic gut hormones glucagon like peptide-1 and peptide YY upon fermentation in the colon.8 Research done to date has included samples with wide age and BMI ranges, various doses of inulin, as well as different study designs. More investigations are needed in specific populations, such as older adults who might have age-related alterations in gastric emptying.9 This pilot research study investigated the effects of short-term pre-meal inulin consumption (10 g, mixed into 500 ml water) on energy intake (EI) and appetite sensations over a 24-hour period, in overweight and obese middle-aged and older adults (n=7, 55-67 years old), in order to determine the potential role of prebiotics in weight loss and weight management. A randomized crossover design was used, with participants completing both pre-meal inulin and control (500 ml water alone) conditions. There were no differences in EI, gram weight, nor energy density of foods consumed between the inulin and control conditions. However, observed subgroup differences suggest variances in response to the inulin preload related to gender, habitual fiber consumption, cognitive dietary restraint, and BMI status. / Master of Science