Regularly consuming caloric beverages has been linked to obesity and weight gain and evidence suggests this is because beverages have a weak impact on satiety responses (behavioural and physiological). Using a series of experimental studies this thesis explored the cognitive and sensory features of caloric beverages that might enhance the anticipated and actual satiating power of their nutrients. Paper one characterised the sensory characteristics associated with expectations of hunger, fullness and thirst, finding that food and beverage products anticipated to be creamier and thicker were expected to be more satiating and less thirst-quenching. Paper two established that people can perceive subtle changes in beverage viscosity and manipulating thick and creamy textural cues strongly influenced the expectation that a beverage would be filling and supress hunger after consumption. This was extended in paper three, which reported evidence suggesting that a sensorially enhanced beverage is selected and consumed in smaller portions. Papers four and five investigated the satiating power of a caloric beverage consumed with satiety-relevant cognitive and sensory information. Paper four reported tentative evidence that a labelled satiety message influenced the satiating effect of caloric beverages when combined with thick and creamy sensory cues. Participants in Paper five reported greater satiety responses to a covert manipulation of beverage energy when consumed as a ‘snack' rather than a drink. However, consuming the same beverage in a subtly thicker sensory context (without extra information) generated the largest satiety response to the different nutrient loads, perhaps because textural characteristics are the most reliable cue for nutrients. Overall these studies suggest that caloric beverages may generate weak satiety responses because their nutrient-generated effects are not expected. Encouraging people to consider caloric beverages as a snack, or adding in nutrient-relevant sensory characteristics, may both help consumers regulate energy intake when consuming these products.

This thesis enhances our understanding of the British Kitchen Front through the examination of primary sources from Mass Observation Archive. It illuminates the everyday life of civilians, the impact of the war food restrictions on their eating habits and practices, but also on their perspectives and behaviours. Moreover, it argues that while the food practices of these civilians were modified by the wartime rationing and food scarcity, other factors of influence, namely social class, personal and familial circumstances and time were critical regarding eating habits, food choice and priorities. In order to conduct this research and respond to the difficulties presented by the sources examined, a tailor-made method of data extraction, categorisation and analysis has been designed. Using the advantages of quantitative and qualitative methodologies, this method allowed an unusual quantitative treatment of massive qualitative data, the creation of measurable and comparable figures as well as their qualitative contextualisation. It was found that scarcity of food effectively modified the diet of the diarists, but also their actions and perspective. The food difficulties generated new behaviours, some unlikely to have existed prior to the war, and modified relationships. The value of food changed as well, modifying its role in private and public sphere. However, as argued, the social class and the familial status of the diarists were a key dimension of the management and perception of the food situation, influencing their choice, decision and priorities as well as their response to it. The passing of time also proved to be influential regarding the adaptation and the evolution of the opinion and feelings of the diarists. Rather than drastically challenging the existent literature, the present research suggests that some interpretative differences concerning the Home Front experience could be the result of a variation of focus and of sources employed, indicating the need to enlarge the historical perspective, to include more in depth analysis of qualitative data, and to take into account the factors of influence presented into this work.

No description available.

The General Organization for Technical Education and Vocational Training, Riyadh, Saudi Arabia, has developed a special feeding program for the students at its institutions. The effects of this program on the nutritional and health status of these students have not been evaluated yet, and since no published dietary research has been performed on Technical and Vocational young adult male students, the present work was undertaken to investigate the nutritional status of this community in Riyadh, Kingdom of Saudi Arabia. After a pilot survey, it was decided to use a selfcompleted questionnaire combined with personal interview to investigate the nutritional status of 690 students randomly selected from the study population. Dietary data was collected by two methods: usual weekly intakes "diet history" and actual daily intakes "diet diary". The nutrient intakes were calculated using the unilever Dietary Analysis Program (UNIDAP). The statistical Package for the social Science (SPSS/PC+) was employed to analyse the data; statistical significance of relationships between certain sets of data was determined by chi-square analysis. Some general factors affecting the nutritional status of these students were identified, their nutritional habits and attitudes were investigated, and the average daily intakes of energy, the macronutrients, and selected micronutrients were calculated. The main results of this study shows that the majority of the study population are adolescent, moderately active individuals, and have lower than the standard range of the Body Mass Index; anaemia is the most stated health problem; meal-skipping and eating between meals are common habits amongst the students. Regarding nutrient intake, there was an energy, polyunsaturated fat, and vitamin C deficiency; adequate intake of saturated fat, dietary fibre, retinol, and zinc; more than adequate intake of protein, total fat, cholesterol, thiamin, riboflavin, calcium, and iron. Recommendations are given which aim to improve the nutrition of technical and vocational students.

A wealth of support has shown higher levels of state and trait impulsivity can be found among those individuals prone to developing problematic eating behaviors and obesity. Thus, upon commencing the investigations in this thesis, it was hypothesized that impulsivity is an individual difference implicated in overeating behaviour. Increasing information indicates that there are divisions within impulsivity subtypes. Prior to this thesis, studies in the field of eating behaviour had not distinguished between subtypes of impulsivity. This was problematic because it limited researchers ability to describe how impulsivity is specifically involved in the perpetuation of overeating behaviour. The purpose of this Thesis was to provide a methodical inquiry into the relationship between impulsivity, and its relation with overeating behaviour. This objective was achieved by separating three prioritites, first to determine if impulsivity was higher in women who self report overeating, second to define differences between impulsivity classifications and determine if there was a consistnent pattern between self reported overeating and a relation to a subtype of overeating behaviour, and third to designate a specific impulsivity subtype to individuals who self report overeating behaviour. Six Experimental Chapters explored these three priorities. Two exploratory correlational/regression analysis were used to refine our ability to operationalize measures of self reported overeating and impulsivity (Chapters 2 and 5). Chapter 3 and Chapter 5 were devoted to assess the impact that ingestion of palatable food, and the violation of cognitive boundaries of restraint, have on subsequent impulsivity. The two remaining investigations were structured to assess the impact that environmental factors have on impulsive behaviour. In Chapter 4, a Controlled versus Unrestricted eating environment were manipulated to determine whether overeaters benefit from a structured breakfast meal prior to completing a battery of impulsivity tasks. In Chapter 7, anticipation for a rewarding food item was manipulated in two conditions. In this final Chapter, the impact that anticipation for rewarding food in self reported overeaters was assessed. The battery of impulsivity tasks in this thesis include the Balloon Analogue Risk Task (BART), The Go No Go task, the Matching Familiar Figures task (MFFT), and two versions of the Delay Discounting Task (DDT). Impulsivity was classified along a spectrum of Reward Reactivity versus Inhibition subtypes, based on Evenden´s (1999) classification of impulsive behaviour. Participants tendency to overeat was based on a dual classification of tendency to restrain eating (Three Factor Eating Questionnaire- Restraint) with tendency to overeat (Three Factor Eating Questionnaire-Disinhibition subscale). The outcomes of the five experimental investigations in this thesis demonstrated a reliable pattern by which participants with high Disinhibition scores had significantly more impulsive responses on the MFFT task. These results indicated that inhibition impulsivity is the clearest individual difference to be found between healthy volunteers who self-report overeating. The role that Inhibition Impulsivity plays in the perpetuation of overeating behaviour is illustrated and discussed in each Experimental Chapter.

This thesis challenges accounts of individual choice and responsibility where food consumption is concerned, beginning with a critique of government policies to address the health effects of over-consumption of food. Whilst research from psychology and economics has acknowledged the role of habit and automaticity in some behaviours, including eating, the resulting theory of behavioural economics and its operationalisation as ‘nudge' theory does not directly address class differences. I argue that sociological analysis can do so, and discuss the trajectory of social class in social theory in recent decades, bringing together the insights of several theorists to challenge both Giddens's concept of reflexivity and postmodern notions of consumerism as an equalising force. I demonstrate that social theory can provide a solid underpinning to behavioural economics, and at the same time show the weakness of its policy applications to healthy eating. Given the relative inattention to the structures that shape dietary ‘choices', in comparison to the study of behaviour, this thesis examines the nature of the food supply and traces how the food industry develops, markets and sites food, and the ways in which it engages, often interactively, with a highly segmented society. The production and targeted supply of processed foods of varying quality contributes to problematic food consumption, particularly among those of lower social status. This phenomenon is further evidenced by an epidemiological review outlining the food-health-class link. Subsequently, I conduct the first sociological analysis of food industry texts (representing food science, product development and marketing), revealing how actors within these disciplines articulate their role, function and concerns regarding current practice. A critique of marketing emerges from both practitioners and marketing academics, and I apply this and an expanded sociological critique to the role of the food supply in diet-related ill health, in which a social gradient is strongly apparent.

Sensory-specific satiety (SSS) is a significantly greater pleasantness decline for a consumed (Eaten) food, than foods that are tasted but not consumed (Uneaten). SSS occurs during consumption, reaches optimal magnitude immediately afterwards, and returns to baseline within two to three hours. The phenomenon is dependent on the sensory properties, rather than the energy or macronutrient content of the food. To the extent that an Uneaten food shares similar sensory properties with the Eaten food, the Uneaten food may be subject to pleasantness decline: a transfer effect. Repeated exposure to a food stimulus may alter liking in the long-term, through mere exposure, monotony, and dietary learning paradigms resulting in an association between the novel target food and either a known food stimulus, or a consequence of consumption. Novel foods are more susceptible to these effects than familiar foods, for which learned associations may have already formed. Repeated consumption alone does not modulate SSS, but to date such studies have not tested novel foods. Through six experiments this research explores the influences of long-term pleasantness changes of novel foods and the number and type of Uneaten foods present during SSS testing, on the magnitude of SSS for snack foods. While no evidence of mere exposure or dietary learning was found, and in some instances experiments failed to induce SSS, these negative results are likely due to methodological, and sometimes procedural issues in the design and conduct of experimental testing. Findings revealed SSS to be vulnerable to a number of procedural and methodological factors, such as: portion size; baseline novelty and pleasantness ratings; hunger; perceived ambiguity of measurement scales; and expectations raised by the type and number of Uneaten foods present during testing.

Dietary restriction (DR) is the only known nutritional manipulation that can increase both lifespan and healthspan in a variety of species. Underlying these increases are improvements in metabolic health and reductions in cancer incidence. Despite these physiological improvements, the regulation of skeletal muscle mass is extremely sensitive to alterations in nutrients [reviewed in (Sharples et al., 2015)] and as such has been reported to reduce regenerative potential and increase atrophy in skeletal muscle cells and myotubes. Interestingly, the activation of Sirtuin1 (SIRT1) has been reported during DR and its reduction abrogates lifespan extension. Importantly, SIRT1 activation via resveratrol treatment has been indicated to be important in the presence of inflammatory stress (TNF-α) (Saini et al., 2012). Resveratrol supplementation has also improved survival and regeneration of skeletal muscle cells as well in muscle cell remodelling following oxidative stress (Bosutti and Degens, 2015). We therefore sought to create an in-vitro physiological model of DR by mimicking levels of glucose in the circulation and interstitium in-vivo in response to DR (Chapter 3) as well as optimising the activation and inhibition of SIRT1 using resveratrol and SIRT1 inhibitor, EX-527 respectively (Chapter 4). With our ultimate aim to investigate the potential role and mechanisms of the activation/inhibition of SIRT1 in ameliorating the degenerative/atrophic effect of DR in both differentiating myoblasts (Chapter 5) and mature myotubes (Chapter 6). Indeed, in Chapter 3 we present two models of reduced glucose; one reduced (medium/ MED) and the other blocked (LOW) differentiation and myotube hypertrophy. The former represented circulatory glucose blood levels (MED 1.13 g/L or 6.25 mM) and the latter interstitial represented glucose levels (LOW 0.56 g/L or 3.12 mM) of rodents under DR. In Chapter 4 we also suggest that within the in vitro muscle cell model, activation/inhibition of SIRT1 phosphorylation (western blot analysis) was thought to be most effective at 10 μM of resveratrol and 100 nM of EX-527 respectively. In chapter 5, we observed that resveratrol treatment did not improve fusion when administered to differentiating myoblasts. Resveratrol did however evoke increases in myotube hypertrophy under normal glucose conditions. Importantly resveratrol enabled improved myotube hypertrophy over an acute 24 h period when administered to existing mature myotubes in low glucose environments. If this finding translates to whole organisms and human populations it could provide healthspan improvements via reductions in fragility associated with loss of muscle mass in individuals undergoing dietary restriction. After this 24 h period resveratrol was unable to reduce myotube atrophy and the myotubes continued to atrophy, suggestive of a need for repeated resveratrol treatment to enable continued protection against muscle atrophy under low glucose conditions. SIRT1 activation increased Myogenic regulatory factor 4 (MRF4) gene expression under LOW glucose conditions which was associated with the observed improvements in myotube size at 24 h. Whereas, SIRT1 activation via resveratrol treatment in normal glucose conditions modulated increased gene expression of Myosin heavy chain 7 (MYHC7) coding for the slow isoform while inhibition of SIRT1 (EX-527) lead to reductions in gene expression of MYHC 1, 2 and 4, coding for faster IIx, IIa, IIb isoforms respectively. Perhaps suggesting that elevated SIRT1 was important in the activation of genes coding for slower myosin heavy chain isoforms. Furthermore, while SIRT activation via resveratrol did modulate increases in IGF-I gene expression, it did not appear to modulate energy sensing AMP activated protein kinase (AMPK) vs. growth related Protein 70 S6 Kinase (p70S6K) signalling pathways. However, SIRT1 inhibition increased AMPK activity in both low and normal glucose with corresponding mean reductions in p70S6K in normal glucose conditions. This indicates that perhaps normal SIRT1 activity was required for appropriate AMPK activation, which may therefore prevent the suppression of p70S6K and the corresponding reductions in myotube size observed in SIRT1 inhibitor conditions. Furthermore, during low glucose induced myotube atrophy resveratrol reduced gene expression of the negative regulator of muscle mass, myostatin and protein degradative ubiquitin ligase enzyme, MUSA1. Overall, SIRT1 activation via a single dose of resveratrol appears to have a role in acutely negating the effect of low glucose induced myotube atrophy and promoting myotube hypertrophy when glucose is readily available.

Within youth soccer high training and match loads warrant appropriate nutritional attention, although research assessing the nutritional intake and habits of youth soccer players is scarce. This thesis aimed to investigate habits and explore experiences of dietary intake methods in an English Premier League youth academy. Study one (Chapter 4) quantified the energy, macro and micronutrient intake of players from age groups under (U) 13 to U18 (7-day food diary, n = 59). Results showed players across all ages were in energy deficit, with low carbohydrate intake, and a large individual variability for micronutrient intake in comparison to current recommendations. However, under-reporting may have influenced these results. Study two (Chapter 5), a qualitative approach, explored nutritional habits (n = 15) with study one participants using one-on-one interviews. The U15 – U18s players consciously periodise their carbohydrate intake throughout the week; U18s stated this was to aid body composition. When discussing their participation in the previous food diary study, U18s expressed that a quicker, more user-friendly method would be desirable. The third study (Chapter 6), therefore, assessed the use of smartphone technology to record dietary intake. Fulltime youth soccer players (n = 22) recorded their dietary intake on a single training day, using a smartphone application and a photography method respectively compared to 24-hr recall. The 24-hr recall provided significantly higher energy and macronutrient intake in comparison to the smartphone methods. This data suggests smartphone technology was more effective in tandem with 24-hr recall. To conclude, youth soccer players are in dietary energy and carbohydrate deficit, with variable micronutrient intake when compared to current recommendations and traditional 24-hr recall is recommend if using smartphone technology. Further research for the accurate quantification of dietary intake and energy demands is required. Dietary advice provision for youth soccer to reach current nutritional recommendations is warranted.

Cardiovascular disease (CVD) is the leading cause of global mortality, with the incidence of cardiovascular related pathologies remaining a public health burden. CVD encompasses pathologies of the vascular tree and heart, including, for example, peripheral artery disease, coronary heart disease and ischaemic stroke. Atherosclerosis is the primary pathological process leading to CVD and is characterised by a multifactorial pathophysiology that first manifests in the vascular endothelium. Termed endothelial dysfunction, this early marker of atherosclerosis has become a focus of interest for identifying individuals at risk of a profound cardiovascular insult, particularly arising from lifestyle choices such as physical inactivity and calorie-rich diets. Dietary interventions have received increasing attention in recent years as inexpensive strategies to potentially combat the ever-increasing global burden of CVD. A high dietary flavonoid intake is associated with a reduction in CVD risk and several studies have revealed a strong, inverse relation between the regular intake of tea, a major source of dietary flavonoids, and CVD risk. Tea has demonstrated improved conduit artery endothelial function and glucose handling in both healthy individuals and in those with overt CVD. However, the effects of tea on the microvasculature and cerebrovasculature are not yet understood, particularly in relation to lifestyle factors. The primary aim of this thesis was to explore the impact of tea ingestion on peripheral and cerebral micro- and macrovascular function in humans. In an initial methodological study, the day-to-day reproducibility of thermally stimulated cutaneous microvascular function was assessed. Fifteen, healthy males (28 ± 5 yrs, BMI 25 ± 2 kg/m2) attended two experimental trials 2-7 days apart. During each trial, baseline and maximal thermally stimulated forearm skin responses were examined simultaneously at four sites on the dominant forearm using laser Doppler flowmetry (LDF). The following heating protocols were adopted: 1. Rapid 39°C (0.5°C/5-s), 2. Rapid 42°C (0.5°C/5-s) 3. Gradual 42°C (0.5°C/2-min 30-s) and 4. Slow 42°C (0.5°C/5-min). The coefficient of variation (CV) was calculated for absolute flux, cutaneous vascular conductance (CVC; flux/mean arterial pressure, MAP) and CVC expressed as a percentage of maximal CVC at 44°C (%CVCmax) at three different time points; baseline (33°C), plateau (39/42°C) and maximal (44°C). Reproducibility of baseline flux, CVC and %CVCmax was 17-29% across all protocols. During the plateau, Rapid, Gradual and Slow 42°C demonstrated a reproducibility of 13-18% for flux and CVC and 5-11% for %CVCmax. However, Rapid 39°C demonstrated a lower reproducibility for flux, CVC and %CVCmax (21%). Reproducibility at 44°C was 12-15% for flux and CVC across all protocols. The good-to-moderate reproducibility of the Rapid, Gradual and Slow 42°C protocols supported their (simultaneous) use to assess peripheral microvascular function. The aim of Chapter 5 was to examine the acute (2-hour) cutaneous vascular responses to local skin heating following ingestion of black tea in a healthy adult population. Twenty healthy participants (58 ± 5 yrs, BMI 26 ± 4 kg/m2, 9 men) attended two experimental trials (tea, placebo), 7-days apart in a randomised, controlled, double-blind, cross-over design. Participants ingested a single dose of 200 ml black tea or placebo, followed by assessment of forearm cutaneous microvascular function using LDF and three distinct local skin heating protocols to distinguish between axon- and endothelium-dependent vasodilation: 1. Rapid 42°C, 2. Rapid 39°C and 3. Gradual 42°C. On the contralateral arm, full-field laser perfusion imaging (FLPI) was used to assess forearm cutaneous microvascular function during Gradual 42°C. Data were analysed as CVC and %CVCmax. Rapid local heating to 39°C or 42°C demonstrated no effect of tea for flux, CVC or %CVCmax (all P > 0.05). Gradual local heating to 42°C, however, produced a higher skin blood flow following black tea ingestion for absolute CVC (P=0.04) when measured by LDF, and higher absolute flux (P < 0.001) and CVC (P < 0.001) measured with FLPI. No effect of tea was found for %CVCmax when assessed by either LDF or FLPI. The aim of the study outlined in Chapter 6 was to examine the effect of daily green tea consumption (equivalent to 6 cups/day) on changes in peripheral vascular function and glucose handling after a 7-day ‘unhealthy’ lifestyle in healthy males. Twelve healthy males (29 ± 6 yrs, BMI 25 ± 2 kg/m2) underwent two periods of 7-days ‘unhealthy’ lifestyle (UL) comprising of combined physical activity reduction (-50% steps per day) and high fat, high carbohydrate overfeeding (+50% kcal per day, comprising 65% fat) in a randomised, controlled, double-blind, cross-over design. Each intervention period was separated by a 2-week washout. During each 7-day UL-period, participants ingested three doses of an active green tea drink (UL-Tea) or a placebo drink (UL-Placebo) per day at regular intervals. Participants attended the laboratory before and after each 7-day intervention (a total of 4 visits). During each visit the following were examined: mean arterial blood pressure (MAP), dominant forearm cutaneous microvascular function using LDF and local heating protocols 1. Rapid 42°C, 2. Rapid 39°C and 3. Gradual 42°C, macrovascular function using brachial artery and femoral artery endothelium-dependent function via flow-mediated dilation (FMD), carotid artery vasoreactivity to the cold pressor test (CAR%), cerebrovascular function via CO2 reactivity and dynamic cerebral autoregulation, and insulin sensitivity and glucose handling through a mixed-meal (1200kcal, comprising 60% carbohydrates, 33% fat and 7% protein) tolerance test. Linear mixed models (main effects of intervention and time) were used to examine the impact of the lifestyle intervention (pre vs post) and green tea ingestion (UL-Tea vs UL-Placebo). Body mass demonstrated a slight increase following both UL-Tea and UL-Placebo (P > 0.05). MAP was increased after UL-Placebo, whereas it was reduced after UL-Tea (P=0.06). LDF responses to rapid local heating demonstrated non-significant reductions in CVC following UL-Placebo but no difference following UL-Tea (P > 0.05), with a significant interaction of time*condition*temperature observed following Gradual 42°C (P=0.02). Brachial artery FMD was not different pre vs post or between UL-Placebo and UL-Tea (P > 0.05), whereas femoral artery FMD decreased after UL-Placebo, which was prevented during UL-Tea (P < 0.001). CAR% decreased following UL-Placebo, which was prevented during UL-Tea (P=0.04). CO2 reactivity and dynamic cerebral autoregulation demonstrated no differences between UL-Placebo and UL-Tea or over time. Postprandial glucose was increased after UL-Placebo, whereas a reduction in postprandial glucose occurred after UL-Tea (P=0.03). Postprandial insulin levels were higher after UL-Placebo, consistent with insulin resistance, whereas following UL-Tea the insulin response was reduced and demonstrated an interaction of time*condition (P < 0.001). The aim of Chapter 7 was to examine the effect of acute oral (-)-epicatechin ingestion on cerebrovascular function in healthy adults. Seven healthy males (32 ± 13 yrs, BMI 25 ± 1 kg/m2) attended two experimental trials ((-)-epicatechin and placebo) 7-days apart in a randomised, controlled, double-blind, cross-over design. Participants underwent baseline assessment of cerebrovascular function using transcranial Doppler ultrasound (TCD), comprising CO2 reactivity to hypercapnia and dynamic cerebral autoregulation via squat-stand manoeuvres at 0.10 Hz and 0.05 Hz. / Following completion of the baseline measures, participants immediately consumed an oral dose of the test product (2 x 50 mg capsules of (-)-epicatechin or 2 capsules of colour-matched placebo) together with a glass of water, following which participants relaxed in the laboratory. 2-hours post-ingestion repeat measures of cerebrovascular function were performed. Linear mixed models (main effects of condition and time) examined the differences between (-)-epicatechin and placebo interventions (pre vs post) on cerebrovascular function. No differences were observed at pre vs post baseline for middle cerebral artery velocity (MCAv) or MAP (all P > 0.05). There were no differences in the cerebrovascular responses to CO2 or dynamic autoregulation between (-)-epicatechin and placebo. The findings from this thesis suggest that, firstly, use of simultaneous skin local heating protocols provides a valuable means of interrogating the cutaneous microvessels for mechanistic insight in intervention studies. Secondly, current findings evidence improved cutaneous microvascular function following acute black tea consumption. Furthermore, the research work undertaken in this thesis provides important insight into the effects of tea consumption on peripheral (micro- and macro-) vascular function and insulin sensitivity, particularly its abrogative effects on lifestyle-induced vascular impairments. However, the effects of tea consumption on the cerebrovasculature remain uncertain. Overall, based on the current findings, tea consumption presents a simple, inexpensive, non-pharmacological cardioprotective strategy to help combat the ever-increasing global burden of CVD.