The steady increase in obesity rates and obesity-related comorbidities has become a worldwide epidemic. In individuals with obesity and overweight, weight loss of just 5-10% of initial weight can significantly improve health and reduce the risk of other serious health conditions. While self-directed attempts at weight loss are often initially successful, in many cases individuals regain some, if not all, of their weight loss. However, when an individual seeking weight loss engages with a qualified practitioner, they are less likely to regain their weight. Although dietitians are arguably the most suitable practitioner to provide this support, oftentimes they are not the practitioner sought out by those seeking to lose weight. Non-dietitian practitioners such as personal trainers, nutrition coaches, sports coaches, and strength and conditioning coaches are frequently approached for nutrition guidance. Even though weight loss maintenance appears to be a common problem worldwide, there is very little research available regarding non-dietitian practitioners, especially from the perspective of the practitioner, with a focus on weight loss maintenance. Therefore, the aim of this dissertation was to conduct quantitative and qualitative research to explore the beliefs and approaches used by successful online weight loss coaches. Firstly, a literature review was conducted to understand the literature regarding weight loss maintenance, the repercussions of weight regain, and the client-practitioner relationship. A survey and semi-structured interviews were undertaken to explore the associations, traits, and qualities associated with online nutrition coaches’ perceived success with their weight loss maintenance clients. The participants in both studies were current or former Diet Doc LLC coaches or National Academy of Metabolic Science (NAMS) graduates. The Diet Doc was specifically chosen because it provides professional support and an evidence-based system for their coaches to operate within, which is also taught in their NAMS nutrition coaching course, thus providing a unique cohort of online nutrition coaches operating in a supported, evidence-based framework. The quantitative survey, n = 16, gathered information on the demographic and professional characteristics of coaches, and the relationships between coaches’ levels of qualification, nutrition qualifications, types of qualification, and years of experience and their self- perceived success rates of client weight loss maintenance. Descriptive statistics were analysed, Spearman’s correlations and Mann-Whitney U tests used to analyse the data, with significance was set at 0.05. 85.8% of the coaches indicated >50% of their clients maintained their weight loss for over one year, 57.1% always discussed mindfulness with their clients, 50% always discussed psychology and sleep and stress management with clients, and 85.8% performed client check-ins weekly. While the relationships with self-perceived success in the survey were not significant, the direction of the relationships were supported by the literature and the perceived client weight loss maintenance success rates were very high, which should prompt further research. The semi-structured interviews, n = 4, provided four key themes strongly supported by the literature: rapport, support methods, a holistic approach, and goal setting. Both the survey and the interviews indicated that this cohort apply evidenced-based practice in their work with weight loss clients. While the statistical analyses were not significant, possibly due to a limited sample size, the demographic information found in the survey was novel and noteworthy. In addition, the findings of both studies are reinforced by the literature. Establishing rapport, frequent interactions with clients, and using holistic and acceptance-based approaches are all recommended practices for coaches seeking to help their clients lose and maintain weight loss. However, further research in this area would be beneficial.