The controversial condition of carbohydrate craving is believed by some researchers to be a defect in the regulation of food intake by an individual. This defect is believed to be responsible for the inability of some persons to control their food intake and therefore their weight. Research was conducted to test the hypothesis that, given a group of carbohydrate cravers and a group of noncravers, the cravers will experience a greater plasma insulin response (concentration and area under the curve) than will the noncravers, and that, because of this higher response, the cravers will experience equal or lower plasma glucose levels during a carbohydrate load. A second hypothesis was that, because of cephalic insulin response due to sensory stimuli, cookies would elicit a greater plasma insulin response than would a glucose solution. This higher plasma insulin response may in part explain the uncontrollable snacking that some individuals experience. The purpose of this research was to attempt to identify a biochemical distinction between persons who crave carbohydrates and persons who do not crave carbohydrates. Eleven overweight female subjects, age 30 to 40, were recruited and divided into two groups, five carbohydrate cravers and six noncravers, based on scores received on a questionnaire that was devised for this study to attempt to distinguish between the groups. A Restrained Eating questionnaire was also administered to the subjects. Both groups had similar, but high, restrained eating scores, indicating that all of the subjects were probably restrained eaters. The eating restraint, as supported by the reported frequency of dieting among the subjects, may well have influenced the subjects' responses to the carbohydrate craving questionnaire. Utilizing these two groups of subjects, two tests were administered. The oral glucose tolerance test was administered, utilizing 75 g of carbohydrate each in the forms of glucose solution and cookies, which were administered in a random order. The tests were administered during the premenstrual phase of the subjects' menstrual cycles, 0-10 days prior to the onset of menstruation. Blood was drawn and assayed for plasma glucose and insulin. The research showed that the cravers experienced a significantly greater plasma insulin concentration and area under the curve than the noncravers, particularly at the 30, 60 and 120 minute time points with the glucose treatment. For the glucose treatment, the cravers experienced plasma insulin concentrations that were 32% to 50% greater than those of the noncravers in the early portion of the test. This supports the hypothesis which states that cravers will experience a greater plasma insulin response to a carbohydrate load than will noncravers. This elevated plasma insulin level may be responsible for the carbohydrate cravings that the individuals experience. There was no significant difference in plasma glucose levels at any time point in either of the tests as compared between the cravers and noncravers, thus supporting the expectation that these levels would be similar between the groups. The hypothesis that cookies would elicit a greater plasma insulin response than would a glucose solution was not supported. Any cephalic insulin response which may have resulted from the sight and smell of the cookies, while not specifically measured, was not strong enough to override the physiological factors that control insulin release. Therefore, the glucose solution elicited a significantly greater plasma insulin concentration than did the cookies in the cravers during the first two hours of the tests, and a significantly greater area under the curve for the cravers at 60 minutes and both groups at 120 minutes. However, the cookies did have an effect on insulin release at the fasting point, causing elevated (x = 79%) plasma insulin levels in three of five subjects who were waiting while others were eating the cookies, as compared with these subjects' fasting insulin levels when they were not exposed to the cookies prior to their glucose test. Another finding was a difference between the groups in fasting plasma insulin concentrations over the 10 day premenstrual portion of their menstrual cycles. The noncravers experienced fasting plasma insulin concentrations that decreased as the onset of menstruation was approached, which would parallel the decrease in progesterone levels. However, the cravers experienced first a decrease in fasting plasma insulin levels to day 3 premenstrual, and then an increase to the level of that found 8-10 day premenstrual. This pattern is contrary to what would be expected as progesterone levels drop, and suggests an altered pattern of progesterone levels in the cravers, although progesterone was not measured in this study. To summarize, in a group of overweight women, carbohydrate cravers and non cravers, the cravers experienced a greater plasma insulin response than did the noncravers for the glucose treatment but not for the cookie treatment, and there was no significant difference between the groups for plasma glucose concentration for either treatment. / Graduation date: 1991

Syfte och frågeställningar Syftet med denna litteraturstudie är att undersöka om det finns stöd i nuvarande forskning för att en fettrik kost är mer effektiv som nutritionsstrategi vid uthållighetsprestationer jämfört med en kolhydratrik kost. Studiens frågeställningar är: Förbättras uthållighetsprestationen av en fettrik kost jämfört med en kolhydratrik kost? Hur påverkas kolhydrat- och fettmetabolismen av en högfett- och lågkolhydratkost? Metod Litteratursökningen genomfördes i databaserna Ebsco, Pubmed och Cinahl. Totalt inkluderades 16 artiklar, 11 artiklar från litteratursökningen i databaserna och 5 artiklar från valda referenslistor. Studierna kvalitetsgranskades med hjälp av SBU:s granskningsmall för randomiserade kontrollerade studier. Resultat I 3 av 16 studier förbättrades uthållighetprestationen vid intag av högfett- och lågkolhydratkost, i 4 av 16 studier försämrades prestationen och i resterande 9 studier sågs ingen signifikant skillnad i prestationen mellan kostinterventionerna. Majoriteten av studierna fick en förhöjd fettoxidation som resultat av en högfett- och lågkolhydratkost men ingen signifikant skillnad gällande blodglukos-, blodinsulin- eller blodlaktatvärde mellan kostinterventionerna. Slutsats Trots en förhöjd fettoxidation och välfyllda glykogenlager finns inte tillräcklig evidens för att påvisa en generell prestationshöjning vid uthållighetsprestationer av en högfettkost jämfört med en högkolhydratkost. Detta troligtvis på grund av nedsatt förmåga hos musklerna att använda glykogen. Resultaten från de studier som ingick i denna systematiska litteraturstudie visar konsekvent en försämrad prestation efter intag av högfett- och lågkolhydratkost vid arbetsintensiteter över 80% av VO2max. Vid arbetsintensiteter omkring 60-70% av VO2max kan prestationen eventuellt förbättras efter intag av högfettkost bestående av 60-70% fett och mindre än 15% kolhydrater. / Aim The purpose of this study is to investigate whether there is scientific evidence that a high fat diet is more effective as a nutrition strategy for endurance performance than a high carbohydrate diet is. The objectives of the study are: Does endurance performance improve by a high fat diet compared by a high carbohydrate diet? How is the metabolism of fat and carbohydrate affected by a high fat and low carbohydrate diet? Method The literature search was conducted in the databases Ebsco, Pubmed and Cinahl. A total of 16 studies was included, 11 studies from the literature search and 5 studies from selected reference lists. The studies quality was audited by SBU: s questionnaire for randomized controlled studies. Results Endurance performance was enhanced after ingesting a high fat- and low carbohydrate diet in 3 of 16 studies and was decreased in 4 of 16 studies. In the remaining 9 studies there was no significant difference in performance between the two trials. A high fat- and low carbohydrate diet resulted in an increased fat oxidation in the majority of the studies but there was no significant difference in bloodglucose-, blodinsulin- or blodlactatelevels between the two trials. Conclusions Despite increased fat oxidation and well-filled glycogen levels there is not sufficient evidence to prove that endurance performance will be enhanced by a high fat diet compared to a high carbohydrate diet. This is probably because of a lower ability of the muscles to use glycogen. The results from this systematic review consequently shows a decreased performance after a high fat- and low carbohydrate diet at work intensities over 80% of VO2max. At intensities around 60-70% of VO2max, the performance can possibly be enhanced after a high fat diet consisting 60-70% of fat and 15% or lower of carbohydrate.

Research data indicates a persistence of elevated muscle glycogen concentration 3 days post-supercompensation in resting athletes. This study expands our earlier findings by determining whether muscle glycogen remains elevated 3, 5, or 7 days post-supercompensation. Seventeen trained male cyclists underwent one bout of exhaustive exercise to deplete muscle glycogen. This was followed by a 3-day consumption of a high carbohydrate/low protein/low fat diet (85:08:07%). Three post-loading phases followed with subjects randomly assigned to either a 3-day, 5-day, or 7-day post-loading maintenance diet of 60% carbohydrate and limited physical activity. Biopsies (50-150 mg) of the vastus lateralis were obtained pre-load (BASELINE), at peak-load (PEAK), and either at 3-day, 5-day, or 7-day post-load (POST). On average, PEAK to POST muscle glycogen concentrations decreased 34, 20 and 46% respectively for the 3-, 5-, and 7-day POST groups. Only the 7-day post-load group's PEAK to POST mean muscle glycogen concentration decreased significantly. In addition, multi-regression analysis indicated that the PEAK glycogen level was the main determinant of the number of days that glycogen levels remained significantly greater than BASELINE. Thus, trained athletes-supercompensated glycogen levels can remain higher than normal for up to 5 days post-loading. The amount of carbohydrate consumed, the level of physical activity, and the magnitude of the glycogen supercompensation determine the interval for which the glycogen levels are elevated.

Topic: Practical aspects of high-carbohydrate dieting in top sport The topic of this thesis is sports nutrition. After a comprehensive summary of current scientific and generally accepted guidelines, the practical part is based on an example of the current state of sports nutrition in one concrete men's basketball team. Subsequently, the practical part combines the knowledge of theory and results of diet analysis of the current nutritional status in the team. The aim of the analytical part of the thesis was to find out the individual and subsequently average data of the monitored file through the registration of weekly eating diaries, both in terms of macro and micronutrients. These data were statistically processed using the program Sportvital-Nutrition (http://www.bonfit.cz/), whose database contains the most comperhensive information about the composition of individual foods and meals, allowing analysis of up to 30 nutritional parameters. The main aim of the application part of the thesis was to design and calculate a sample menu for seven whole days for top athletes based on predetermined and defined criteria based on theoretical background and analysis of collected eating diaries. These criteria were to follow the principles of healthy nutrition, i.e. primarily the variety, regularity and...

Thesis (Ph.D.)--Ohio University, August, 2009. / Release of full electronic text on OhioLINK has been delayed until September 1, 2012. Includes bibliographical references (leaves 157-195)

Thesis (Ph.D.)--Ohio University, August, 2009. / Title from PDF t.p. Release of full electronic text on OhioLINK has been delayed until September 1, 2012. Includes bibliographical references (leaves 157-195)

Methylglyoxal (MG) is a reactive dicarbonyl compound mainly formed during glucose and fructose metabolism. Diabetic patients have increased plasma levels of MG. Our laboratory has shown that treatment with MG induces insulin resistance and type II diabetes in male Sprague-Dawley rats. However, the increases in endogenous MG level attained in different organs and its contribution to the pathogenesis of diabetes following the administration of either high glucose or high fructose diet have not been addressed. The present study aims to investigate whether the harmful effects induced by increased consumption of glucose and/or fructose is linked to increased MG generation. In vitro studies have suggested that L-arginine is an effective MG scavenger. Accordingly, another goal is to determine whether L-arginine pretreatment would scavenge MG under in vivo setting and reduce the harmful effects of hyperglycemia. MG and reduced glutathione (GSH) levels were determined in plasma and urine and in different organs of male Sprague-Dawley rats after 12 weeks of treatment with either high fructose or high glucose diet. GSH plays an important role in the degradation of MG and bears an inverse relationship with the levels of MG. The key results obtained suggest that both diets significantly increased blood pressure and plasma MG levels. A high fructose but not a high glucose diet, increased the plasma total cholesterol, triglycerides levels and total cholesterol/HDL ratio in parallel with the increases in MG and GSH levels in the liver. Increased MG levels seen in both aorta and mesenteric artery induced by high glucose or fructose diet was attenuated by pretreatment with L-arginine. These findings suggest that elevated MG level induced by treatment with high carbohydrate diets in both conduit (aorta) and resistance type (mesneteric artery) vessels may be linked to endothelial dysfunction seen in hyerglycemic/diabetic states. High glucose but not high fructose diet significantly increased MG levels in the pancreas. This observation is consistent with the well-known glucotoxicity caused by hyperglycemia in the pancreas. Taken together, these data provide the first evidence that elevated MG levels in certain organs/tissues following consumption of high fructose and/or glucose diet(s) may play a critical role in contributing to the metabolic abnormalities and the endothelial dysfunction that precedes the onset of macro and microvascular complications in either hyperglycemic and/or type II diabetic states. Interestingly, quenching of elevated MG levels in tissues by pretreamtent with L-arginine overcomes MG-induced vascular damage and endothelial dysfunction caused by high fructose and high glucose diet regimens.

Digestible carbohydrate is commonly encountered by chinook salmon {Oncorhynchus tshawytscha) in practical culture diets, although little is known regarding its utilization. This study was undertaken to examine (1) the effects of a high carbohydrate diet and (2) glucose tolerance in chinook salmon of selected British Columbia strains. Yearling chinook salmon of three strains were fed to satiation either a high or a low carbohydrate diet for 63 days. The diets were isonitrogenous, and contained respectively 30 % gelatinized wheat starch or an equicaloric amount of herring oil. There was an overall reduction in growth of chinook fed the high-carbohydrate diet over the 63-day feeding period. Although specific growth rates declined initially in the high carbohydrate-fed groups, they were comparable to those of control groups in the final third of the trial, indicating an adaptation response. Chinook fed the high carbohydrate diet had increased carcass protein and ash, and decreased carcass fat levels relative to controls. Feed intake was generally lower in these groups, and differences in feeding response were observed between diets and strains. Although feed and energy efficiencies were reduced in chinook fed the high carbohydrate diet, protein utilization was comparable on the two diets, indicating a protein-sparing effect of the carbohydrate. Consumption of the high carbohydrate diet led to significant elevations in hepatosomatic indices (HSI) and liver glycogen (LG) concentrations. In Quesnel chinook, LG levels exceeding 10 % did not appear to have any detrimental effects on feeding, growth or health. LG concentrations and HSI fell to basal levels in all groups 21 days after feed withdrawal. Some strain differences were evident. For example, Big Qualicum chinook fed the high carbohydrate diet exhibited the lowest liver glycogen accumulation, highest rate of carcass fat deposition, and best energy efficiency ratios relative to control groups, suggesting a difference in carbohydrate metabolism in this strain. On the other hand, Quesnel chinook exhibited the highest relative growth on the high carbohydrate diet. Mortality, although unaffected by diet in the Quesnel and Robertson Creek chinook, appeared to be higher in high carbohydrate-fed Big Qualicum chinook. In the second part of the study, chinook salmon subjected to an oral glucose tolerance test displayed pronounced and persistent hyperglycaemia, indicative of poor glucose tolerance. Strain differences were evident in the magnitude of response. Acclimation to a high carbohydrate diet prior to testing resulted in a significantly reduced elevation of blood glucose, indicating an adaptation response. While plasma glucose concentrations approached 500 mg/dl in some trials, plasma insulin concentrations exhibited a two-fold rise, with indistinct peaks. Plasma glucose and plasma insulin concentrations were poorly correlated, indicating that glucose is a poor insulin secretagogue in chinook salmon. / Land and Food Systems, Faculty of / Graduate

Six white volunteer males less than 35 years old, who ran less than 35 miles per week completed a loading regimen. This consisted of a succession of mixed, high-fat and highCHO diets for at least 72 hours each. Subjects ran to exhaustion after each diet stage. Mean times to exhaustion were 61, 63 and 95 minutes for the mixed, high-fat, and high-CHO diets, respectively. Since questions have been raised concerning a detrimental effect of CHO-loading on heart function, subjects were closely examined for evidence of negative effects associated with this procedure. An incomplete right bundle branch block (RBBB), sinus arrhythmia, and early repolarization after the mixed diet was noted in three of the six subjects. These changes were not observed during the high-fat nor high-CHO diets. Prior to the high-CHO exhaustive run, it was also found that the width of the QRS complex was significantly more narrow than the mixed and high-fat diets. The above electrocardiographic (ECG) changes were noted as not being clinically significant by an internal medicine physician. No changes were noted in blood pressures, serum free fatty acids (FFA) and post exhaustive run body weights for diets not pre/post exercise bouts. Serum glucose was significantly higher for the pre-run high-CHO diet when compared to the mixed and high-fat diets pre-run values, yet it remained within normal limits. Body weight following the high-CHO diet was significantly greater than during the high-fat and mixed periods. This may be due to water retention occurring with increased glycogen storage. This probably explains the longer time to exhaustion for the high-CHO diet as compared to the mixed and high-fat trials which both yielded similar times to exhaustion. Although research indicates that a mixed diet prolongs the onset of exhaustion more than a high-fat diet, the similar endurance capacity for the high-fat and mixed diets could be related to a learning effect on the treadmill and/or psychological considerations of consuming a high-fat diet. Also since heart rate and blood pressure were not significantly different for the first 30 minutes of exercise while rate of perceived exertion (RPE) indicated the mixed diet trial most demanding and the high-CHO trial least, one might suspect that some other factor besides physiological values, may cause fatigue. In summary, CHO-loading appeared to enhance endurance of the novice runner with no apparent detrimental effects on cardiac function in these six subjects. / Master of Science

TITLE: Calories vs. Composition: The effect on dietary alterations on anthropometric measures and biochemical parameters in overweight women.LEARNING OUTCOME: To determine if a high-protein, low-carbohydrate, ad-libitum diet is more effective than an energy-restricted diet in promoting weight loss and improving blood lipid and insulin levels.ABSTRACT TEXT: Thirty overweight/obese (BMI: 25-35kg/m2), premenopausal women were matched for Body Mass Index (BMI) and randomly assigned to one of the two diets: (1) High Protein (HP) (30-40% protein, 40-55% fat, 10-20% CHO); (2) Energy Restricted (ER) (1200kcal/d, 20-25% fat, 15-20% protein, 55-60% CHO). Subjects were given weekly menus matching their assigned macronutrient and/or energy requirements to aid in meal planning and dietary compliance. Baseline and post-diet measures included height, weight, body composition, blood lipids (total cholesterol (TC), HDL, LDL< and triglycerides (TG)], and plasma insulin levels. There were no significant differences found among the two groups in any of the above-listed variables prior to the study. Twenty-three women completed the 6-week study (HP=11, ER= 12). Compliance to the diets was adequate as indicated by weekly 24-hour recalls and daily urinary ketone levels. Both groups lost a significant amount of weight and body fat (P<0.05), andweight and body fat losses were not significantly different between the groups. In addition, both groups experienced similar decreases in TG, TC, LDL, HDL, and insulin levels. These results indicate that a HP diet is no more effective than an ER diet in promoting favorable changes in body weight, body composition, blood lipids, and insulin levels. / Department of Family and Consumer Sciences