Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Food Science." Includes bibliographical references.

Thesis (Ph. D.)--UCLA, 2009. / Vita. Description based on print version record. Includes bibliographical references (leaves 72-100).

Thesis--Ph. D., University of Hong Kong. / Mimeographed.

Thesis (M. Phil.)--University of Hong Kong, 2002. / Includes bibliographical references.

Background: Unhealthy lifestyle are important contributors to chronic illness in Hong Kong and worldwide. Lifestyle modification, particularly improving healthy diet and physical activity, can prevent the development of various chronic illnesses, improve disease conditions, reduce the risk of complications and enhance the quality of life. Many behavioural models have been applied to achieve lifestyle modification, but the major limitation was that they mainly treated human behaviours as individual behaviours that were subsequent to rational thinking. Nudge theory, an advanced behavioral concept, proposed to change individual’s motivation, incentives and decision making through non-direct suggestion and non-forced reinforcement. However, the application of Nudge theory has been challenged on the lack of evidence to prove its effectiveness, and its controversial framework for ethical analysis. Objectives: This review was to synthesize the empirical findings about the effectiveness of using nudge theory for lifestyle modification including healthy diet and physical activity. Methodology: Interventional and experimental studies that were conducted based on Nudge theory to change diet or physical activity was identified from the published literature. The studies were divided into two large groups according to outcome measured: healthy diet and physical activity, and they were systematically synthesized. The “nudges” used in these studies were categorized as six types of “nudges” summarized by “nudge unit” as “MINDSPACE” for further discussion. The type of “nudges” that were used in the studies and their effectiveness on changing diet and physical activity was abstracted. Results: Totally, nine articles that met the inclusion criteria were included. Five nudges were identified from the included studies, including Priming (P), Default (D), Salience & Affect (SA), Incentives (I) and Messenger & Norms (MN). It is found that the strategies and methods applied on the same nudge may have different effectiveness. Seven studies applied Priming (P) as nudge to motivate change in diet, which used two major strategies: “availability” and “accessibility”. The evidence was strong that altering the availability of food presence could be effective to change food selection. The results of studies using accessibility were heterogeneous and contradictive with each other. Another three studies used different nudges including Default, Salience & Affect and Incentive. The effectiveness of Default (D) as nudge seemed to be blurry, and the sustainability remained questionable. The ethical consideration is always the primary pillar for applying nudging theory. As long as the applications are stick to necessary ethical concerns, the nudging model can be beneficial through mild “manipulation” rather than harmful. Conclusion: It has potential opportunity to carry out “libertarian paternalism” in Hong Kong. However, it is still a long way to take application of nudging model into regulation, legislation and daily practice. The evidences for each type of nudge were not consistent and enough. Besides, the monitoring and evaluation are not available yet. Future research can be focused on transferring these applications into real practice with an effective monitoring and evaluation system. / published_or_final_version / Public Health / Master / Master of Public Health

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Bakgrund Antalet bloggar som skrivs av hälsoprofiler med förslag på dieter och olika kostråd blir allt fler. Dessa sprids sedan i olika sociala medier. I sökandet efter alternativ till Livsmedelsverkets kostråd kan gruppträningsinstruktörer vara personer som ses som en hälsoförebild inom såväl träning som kost. De kan också vara en möjlig kanal utåt sett för olika kostbudskap. Syfte Att skapa en översiktsbild kring området kost och kvinnliga gruppträningsinstruktörer. Metod En webbaserad enkät utformades och instruktörer vid två olika träningsanläggningar i Sverige tillfrågades att delta. Totalt deltog 101 personer och svaren sammanfattades och analyserades med statistiska test. Resultat Av instruktörerna följer 11 % någon typ av diet medan ungefär 20 % utesluter laktos eller livsmedel med gluten. Många har någon typ av kostutbildning men en hel del vill ha mer kunskap, framför allt de yngre instruktörerna (< 30 år) (p=<0,05). Instruktörerna får frågor om kost som främst handlar om vad man bör äta i samband med träning och/eller viktnedgång. De instruktörer som instruerar fler än fyra pass per vecka får oftare frågor än de instruktörer som instruerar fyra pass eller färre (p=<0,05). Slutsats Gruppträningsinstruktörer utesluter möjligtvis en viss typ av livsmedel i större utsträckning än övriga befolkningen. För att kunna säga att det finns en skillnad mellan grupperna behöver dock fler studier göras. Större och mer omfattande studier är önskvärt för en större förståelse kring varför livsmedlen utesluts men också för hur instruktörer ser på sig själva i rollen som hälsoförebild och hur det påverkar dem. / Background There are numerous blogs written by people who see themselves as health authorities. They provide suggestions on how you, as a person, should eat. Within social media, this number is increasing exponentially in regards to advice. Many fitness instructors, who are easily perceived as superior in knowledge within the subject, can be a group asked for information when someone looks beyond the Swedish Food Administration for recommendations on diets and health. Hence, instructors can be a possible “channel” out for dietary advice. Objective To create an overall upper perspective on diets and female fitness instructors. Method(s) A web-based questionnaire was used and instructors from two fitness centers in Sweden were asked to participate in the study. The 101 replies were summarized and analyzed with statistical tests. Results By the instructors, 11% follow some type of diet and about 20 % exclude lactose and/or gluten. Many of the instructors have some type of nutrition education but more knowledge is desirable by the younger instructors (< 30 years)(p=<0,05). The instructors were asked questions about food and more specifically what you should eat in connection to training and/or weight loss. The instructors who have more than four classes per week were given more questions than the ones who carry out less than four classes per week (p=<0,05). Conclusion This study indicates that female group fitness instructors, to a greater extent than the population as a whole, exclude specific kinds of food. Although, to say there is a difference between fitness instructors and the population, more studies are needed. A larger study would be needed to better understand why some foods are excluded but also to explore how the instructors see themselves as a health role model and how it affects them.

There is accumulating evidence that several diet and lifestyle factors affect breast cancer risk. One of the proposed mechanisms behind this is DNA methylation which has been observed in breast cancer, even in the very early stages, and may be altered in response to these risk factors. There is also growing interest in the detection of aberrant DNA methylation in non-tumour cells which could be utilised for breast cancer screening. The main questions addressed were: whether B vitamin intake and lifestyle factors were associated with breast cancer risk and DNA methylation and whether DNA methylation within whole blood or buccal cell DNA was associated with breast cancer risk. Samples were obtained from controls and women newly diagnosed with breast cancer and Pyrosequencing™ technology was used to analyse the percentage methylation of LINE-1, BRCA1, ER , p16, MGMT, RAR 2, RASSF1A, and ALDH2 in both sample types. Information on B vitamin intake, alcohol, smoking, physical activity, and reproductive factors was obtained via questionnaire Hypermethylation of ER was associated with a decreased risk of breast cancer and a positive correlation was observed between methylation of ER and BRCA1. After adjustment for ER methylation, results suggested that BRCA1 hypermethylation was associated with an increased breast cancer risk. This provides support for extension of 'field effect' concept and the utility of non-tumour cells in breast cancer screening. Associations were observed between B vitamin intake, lifestyle and both breast cancer risk and DNA methylation. Smoking was associated with an increased risk of premenopausal breast cancer, hypermethylation of BRCA1, and hypomethylation of LINE-1 but in postmenopausal women, results suggest a decreased risk and hypomethylation of p16. Alcohol was associated with an increased risk of breast cancer, hypomethylation of BRCA1, and hypermethylation of p16 in women with the lowest folate intakes but not in those consuming higher amounts.

No description available.

Background Obesity is increasing worldwide and is a major contributor to morbidity and mortality. Notably, abdominal (central) obesity carries a high risk of obesity-related diseases, while peripheral fat accumulation can act in a protective manner. A redistribution of fat from peripheral to central depots is seen after the menopause and is associated with an increasing prevalence of diabetes and cardiovascular disease. A key mediator may be ectopic fat accumulation in the liver. Our hypothesis was that a Palaeolithic-type diet (PD) consumed ad libitum improves body composition and metabolic risk markers, including liver fat and insulin sensitivity, in obese postmenopausal women. Methods In study I the study subjects (n=10) used a PD during 5 weeks. In study II and III (n=70) the effect of a Palaeolithic-type diet (PD) was compared to a diet according to the Nordic Nutrition Recommendations diet (NNR) during a 2-year randomized clinical trial (RCT). Food records and nitrogen excretion in urine validated food intake. Anthropometric measurements were performed in a standardized manner. Body composition was calculated using Dual Energy X-ray Absorptiometry (DXA). Total energy expenditure was calculated by accelerometry (Actiheart®) in combination with indirect calorimetry. Liver and muscle fat content was estimated by magnet resonance spectroscopy (1H-MRS). Insulin sensitivity was measured either with hyperinsulinemic euglycemic clamps (paper I) or oral glucose tolerance tests (OGTTs) (paper III). Results In study I a significant weight loss, linked to improved lipid and blood pressure levels, was associated with a 49% decrease in liver fat. Concomitantly, hepatic insulin sensitivity improved, while peripheral insulin sensitivity (and muscle fat) was unaltered. In study II/III both groups had a significant and sustained weight loss after 2 years. The PD was more effective than the NNR diet regarding loss of weight and fat mass after 6 months, but not after 24 months. Serum triglyceride levels were significantly lower at 24 months in the PD group. Liver fat decreased throughout the study in both groups. Hepatic insulin sensitivity improved during the first 6 months of the study, while peripheral insulin sensitivity did not change. Hepatic insulin sensitivity was associated with liver fat at baseline, but not during the diet intervention. Energy expenditure did not change in any of the study groups. Conclusion Ad libitum diets can have sustained beneficial effects on weight and body composition in obese postmenopausal women, a PD being more effective on short-term than a diet according to the NNR. This is associated with a reduction in liver fat that may reduce the risk of future diabetes and cardiovascular disease. Further studies are needed in order to explore the association between liver fat and metabolic dysfunction, including insulin sensitivity.