Obesity prevention interventions in young adults

Nikolaou, Charoula Konstantia (2014) Obesity prevention interventions in young adults. PhD thesis, University of Glasgow.

Abstract

Background:
Obesity has emerged as a major public health problem across the globe. Unfortunately, all the efforts, to date, to treat obesity have limited success. Despite the increased publicity on health and economic consequences, its prevalence continues to rise, even in countries that were previously battling under-nutrition. The annual weight gain which may lead to obesity if it remains uncontrolled, is small, averaging 0.7-1.0kg/year. Aiming to halt this small weight gain could be a solution towards combating the obesity epidemic and thus reduce its prevalence. One of the critical life stages where weight gain occurs is the transition between adolescence and young adulthood and especially evident in those attending higher education in the US. There is very limited data from the UK on the magnitude of weight gain in this population. This thesis aimed to explore the weight changes occurring during that life-stage, identify factors affecting those weight changes, explore weight gain prevention data and design and test interventions aiming to prevent any weight gain.
Methods:
Several studies were carried out during this PhD programme in order to answer all the research questions. Three systematic reviews were employed to examine 1) weight changes in young adulthood, 2) weight gain prevention studies in young adulthood and 3) the effect of calorie-labelling on calories purchased as an anti-obesity measure. A pilot study was carried out to test and explore methodologies for collecting data from young adults on lifestyle and lifestyle changes. A qualitative study was carried out to supplement the data from the pilot study on the importance of any weight changes for young adults. A prospective cross-sectional study was carried out to examine the weight changes and lifestyle changes occurring during the first year of studies in young adults. An interrupted time-series study was carried out to test the hypothesis that calorie-labelling might have an effect on preventing weight gain in young adults. A cross-sectional study was carried out to test the effect of calorie-labelling on sales and choices in independent catering facilities where young adults represent a significant proportion of the customers. Lastly, a randomised trial was carried out to test the hypothesis than on-line programmes based on two different behavioural theories could help young adults to avoid any unwanted weight gain.
Results:
The systematic literature review of weight changes in young adults identified 27 studies reporting a mean weight increase of 0.7-3.75kg in those attending higher education. The pilot study examining methodologies and weight changes in young adults attending higher education in the UK found a weight increase between 0.5-5.5kg by 56% of the participants and the best recruitment method to be the on-line method compared to mail or in-person recruitment. The prospective study that looked at weight changes among first-year students attending a large university in the UK found a weight change of 1.8kg in a 9-month period. Baseline weight explained 48% of the variation observed in weight changes. Despite the belief that physical activity or consumption of fruit and vegetables is linked to weight management, neither of these protected against weight gain. The literature review on weight gain prevention studies among young adults, identified twelve studies (five of those conducted in higher education settings). Six of the studies found an effect on preventing weight gain or maintaining weight. No specific techniques were identified to be more effective as the studies that found an effect followed similar techniques with those that did not. The systematic review and meta-analysis on the effect of calorie-labelling on calories chosen/purchased identified seven studies. Overall, there was no effect of calorie-labelling on calories chosen/purchased, however customers noticing the calorie-labels, reduced the calories chosen/purchased by 124.5kcal. Students are generally supportive of the presence of calorie information in a range of products and settings including alcohol products. In the time-interrupted study which was conducted over two years, young adults that were exposed to calorie information did not gain the expected weight observed in young adults in the same setting in the year prior to the implementation of calorie-labelling. The cross-sectional study conducted in an independent catering outlet examined the effect of calorie-labelling on sales of products. Prominent calorie-labelling led to substantial reduction in sales of all labelled products but mostly among those that were high calorie products. The randomised controlled trial led to weight loss among those who were randomised to the intervention groups while those in the control group gained the anticipated weight over a 9-month period.
Conclusion:
Young adults in the UK gain weight when starting higher education. The weight-gain is similar to that observed in young adults in higher education in other countries but higher than the weight gain observed in the general population. Interventions based on different behavioural models were all successful at abolishing this weight–gain. Applying these interventions in a larger scale or making them part of future public health policies could be a significant step towards halting the obesity epidemic.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: Obesity, prevention, young adults, calorie-labelling, interventions, on-line, weight-gain.
• Subjects: R Medicine > R Medicine (General); R Medicine > RA Public aspects of medicine > RA0421 Public health. Hygiene. Preventive Medicine
• Colleges/Schools: College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing > Centre for Population and Health Sciences
• Supervisor's Name: Lean, Professor Mike and Hankey, Dr. Catherine
• Date of Award: 2014
• Depositing User: Miss Charoula-Konstantia Nikolaou
• Unique ID: glathesis:2014-5795
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 05 Dec 2014 10:44
• Last Modified: 11 Dec 2014 15:25
• URI: https://theses.gla.ac.uk/id/eprint/5795