Effect of diet versus diet and exercise on weight loss and body composition in class II and III obesity: A systematic review

Class II and III obesity (BMI >35 kg·m2) have increased dramatically in recent years. Current clinical guidelines suggest diet and exercise as first line treatment for adults throughout the spectrum of overweight and obesity. However, to date there is no systematic review that examines the effects of diet and exercise on this high risk population. This systematic review will examine the combined effects of diet versus diet and exercise on body composition in severe obesity. Medline and Cinahl were searched for randomised controlled trials comparing diet and exercise to diet alone. Studies published until July 2013 were included if they used reliable methods for analysing body composition in adults with BMI ≥ 35 kg·m2. Five of 459 studies met the inclusion criteria. Two studies, both in older adults, reported that exercise reduced lean mass loss during weight loss. Two studies showed that exercise facilitated (greater) fat mass loss. The remaining study reported no differences in body composition when exercise is added to energy restriction. Exercise training during energy restriction for individuals with BMI ≥35 kg.m2 may influence body composition outcomes but the evidence is limited. Further studies should focus on the efficacy of different exercise protocols during energy restriction for this population in order to better inform decision making for the treatment of severe obesity in respect to favourable body composition outcomes.

Factors influencing women’s choice of weight-loss diet

Women's motives for weight-loss dieting and choice of method were investigated in 151 current and 182 prospective dieters. Problematically, appearance-motivated dieters preferred ‘fad’ diets with the promise of quick results, and prospective dieters preferred marketing information supporting such diets over health advice cautioning against their use.

The clinical effectiveness and cost-effectiveness of bariatric (weight loss) surgery for obesity: a systematic review and economic evaluation

To assess the clinical effectiveness and cost-effectiveness of bariatric surgery for obesity. Seventeen electronic databases were searched [MEDLINE; EMBASE; PreMedline In-Process & Other Non-Indexed Citations; The Cochrane Library including the Cochrane Systematic Reviews Database, Cochrane Controlled Trials Register, DARE, NHS EED and HTA databases; Web of Knowledge Science Citation Index (SCI); Web of Knowledge ISI Proceedings; PsycInfo; CRD databases; BIOSIS; and databases listing ongoing clinical trials] from inception to August 2008. Bibliographies of related papers were assessed and experts were contacted to identify additional published and unpublished references. Two reviewers independently screened titles and abstracts for eligibility. Inclusion criteria were applied to the full text using a standard form. Interventions investigated were open and laparoscopic bariatric surgical procedures in widespread current use compared with one another and with non-surgical interventions. Population comprised adult patients with body mass index (BMI) > or = 30 and young obese people. Main outcomes were at least one of the following after at least 12 months follow-up: measures of weight change; quality of life (QoL); perioperative and postoperative mortality and morbidity; change in obesity-related comorbidities; cost-effectiveness. Studies eligible for inclusion in the systematic review for comparisons of Surgery versus Surgery were RCTs. For comparisons of Surgery versus Non-surgical procedures eligible studies were RCTs, controlled clinical trials and prospective cohort studies (with a control cohort). Studies eligible for inclusion in the systematic review of cost-effectiveness were full cost-effectiveness analyses, cost-utility analyses, cost-benefit analyses and cost-consequence analyses. One reviewer performed data extraction, which was checked by two reviewers independently. Two reviewers independently applied quality assessment criteria and differences in opinion were resolved at each stage. Studies were synthesised through a narrative review with full tabulation of the results of all included studies. In the economic model the analysis was developed for three patient populations, those with BMI > or = 40; BMI > or = 30 and < 40 with Type 2 diabetes at baseline; and BMI > or = 30 and < 35. Models were applied with assumptions on costs and comorbidity.

Effective strategies for weight loss in post-partum women: a systematic review and meta-analysis

Post-partum weight loss is critical to preventing and managing obesity in women, but the results from lifestyle interventions are variable and the components associated with successful outcomes are not yet clearly identified. This study aimed to identify lifestyle intervention strategies associated with weight loss in post-partum women. MEDLINE, EMBASE, PubMed, CINAHL and four other databases were searched for lifestyle intervention studies (diet or exercise or both) in post-partum women (within 12 months of delivery) published up to July 2014. The primary outcome was weight loss. Subgroup analyses were conducted for self-monitoring, individual or group setting, intervention duration, intervention types, the use of technology as a support, and home- or centre-based interventions. From 12,673 studies, 46 studies were included in systematic review and 32 randomized controlled trials were eligible for meta-analysis (1,892 women, age 24-36 years). Studies with self-monitoring had significantly greater weight lost than those without (-4.61 kg [-7.08, -2.15] vs. -1.34 kg [-1.66, -1.02], P = 0.01 for subgroup differences). Diet and physical activity when combined were significantly more effective on weight loss compared with physical activity alone (-3.24 kg [-4.59, -1.90] vs. -1.63 kg [-2.16, -1.10], P < 0.001 for subgroup differences). Lifestyle interventions that use self-monitoring and take a combined diet-and-exercise approach have significantly greater weight loss in post-partum women.

The role of the fatosphere in fat adults' responses to obesity stigma: a model of empowerment without a focus on weight loss

Obese adults face pervasive and repeated weight-based stigma. Few researchers have explored how obese individuals proactively respond to stigma outside of a dominant weight-loss framework. Using a grounded theory approach, we explored the experiences of 44 bloggers within the Fatosphere--an online fat-acceptance community. We investigated participants' pathways into the Fatosphere, how they responded to and interacted with stigma, and how they described the impact of fat acceptance on their health and well-being. The concepts and support associated with the fat-acceptance movement helped participants shift from reactive strategies in responding to stigma (conforming to dominant discourses through weight loss) to proactive responses to resist stigma (reframing "fat" and self-acceptance). Participants perceived that blogging within the Fatosphere led them to feel more empowered. Participants also described the benefits of belonging to a supportive community, and improvements in their health and well-being. The Fatosphere provides an alternative pathway for obese individuals to counter and cope with weight-based stigma.

Weight loss and attrition in overweight and obese young women during a 36- week internet-based lifestyle intervention

Background: Young women are at high risk of weight gain yet few studies have examined the long-term effectiveness of weight loss programs in this group. This study aimed to investigate the effects of a self-directed internet-based lifestyle program on body weight in young women.

Methods: Overweight or obese young women (BMI 33.4 ± 0.3 kg/m2, age 27.8 ± 0.3 years) were initially randomized to General lifestyle advice (G) or Structured lifestyle advice (S) via in-person and website support for 12 weeks (Phase I). After Phase I, all participants were supported through a self-directed internet-based program for 36 weeks (Phase II). The internet-based program included a structured hypocaloric diet, physical activity program, self-monitoring tools, peer group forum and monthly emails. Body weight, energy intake and physical activity were measured at week 0, week 12, week 24 and week 48. Adherence to self-regulatory behaviors was measured at week 48. Mixed model analyses were conducted to determine changes in body weight, energy intake and physical activity.

Results: A total of 203 overweight or obese young women commenced Phase I and 130 commenced Phase II. In Phase I, S group had significantly greater weight loss than G group (4.2 ± 0.6 kg vs 0.6 ± 0.3 kg, P<0.001). In Phase II, both groups had significant weight loss over time without significant group differences (-0.8 ± 1.1kg vs -0.8 ± 0.6, P>0.05). Forty-one percent (53/130) of the participants who commenced Phase II completed the internet-based intervention. Dropouts had a higher baseline BMI, were more likely to be married or in a de facto relationship, and more likely to have at least one child.

Conclusions: A self-directed internet-based program could be effective in providing support in maintaining weight loss on a structured lifestyle program in young women over 36 weeks. Further research is required to maintain engagement in young women who were married/in a de facto relationship or have children.

Factors influencing women's choice of weight-loss diet

We developed a typology of eight minimally overlapping weight-loss diet methods and used it to survey 151 women dieters on their choice of diet in the previous 12 months, their motivations to diet, and their eating disorder symptomatology. Canonical correlations revealed a potentially problematic "thin, quick, and easy" association of methods and motives, as well as a more healthful "thin, natural, life-style" association. Both featured the pursuit of thinness but not health. In fact, health was rated by dieters as the poorest motivator of dieting. The results highlight the importance to women dieters of short-term aesthetic concerns over long-term health.

A systematic review of the impact of weight loss on cancer incidence and mortality

Obesity is well recognized as a significant risk factor for certain cancers; however, a corresponding risk reduction with weight loss is not yet clearly defined. This review aims to examine the literature investigating the effect of all types of weight loss on cancer incidence and mortality, and to more clearly describe the relationship between these two factors. A literature search identified 34 publications reporting weight loss data in relation to cancer incidence or mortality. All except one were observational studies and the majority used self-reported weights and did not define intentionality of weight loss. 16/34 studies found a significant inverse association between weight loss and cancer incidence or mortality. The remainder returned null findings. The observed association was more consistently seen in studies that investigated the effect of intentional weight loss (5/6 studies) and the risk reduction was greatest for obesity-related cancers and in women. In conclusion, intentional weight loss does result in a decreased incidence of cancer, particularly female obesity-related cancers. However, there is a need for further evaluation of sustained intentional weight loss in the obese with less reliance on self-reported weight data and more focus on male populations.

Screen-time weight-loss intervention targeting children at home (SWITCH): a randomized controlled trial

BACKGROUND: Screen-based activities, such as watching television (TV), playing video games, and using computers, are common sedentary behaviors among young people and have been linked with increased energy intake and overweight. Previous home-based sedentary behaviour interventions have been limited by focusing primarily on the child, small sample sizes, and short follow-up periods. The SWITCH (Screen-Time Weight-loss Intervention Targeting Children at Home) study aimed to determine the effect of a home-based, family-delivered intervention to reduce screen-based sedentary behaviour on body composition, sedentary behaviour, physical activity, and diet over 24 weeks in overweight and obese children.

METHODS: A two-arm, parallel, randomized controlled trial was conducted. Children and their primary caregiver living in Auckland, New Zealand were recruited via schools, community centres, and word of mouth. The intervention, delivered over 20 weeks, consisted of a face-to-face meeting with the parent/caregiver and the child to deliver intervention content, which focused on training and educating them to use a wide range of strategies designed to reduce their child's screen time. Families were given Time Machine TV monitoring devices to assist with allocating screen time, activity packages to promote alternative activities, online support via a website, and monthly newsletters. Control participants were given the intervention material on completion of follow-up. The primary outcome was change in children's BMI z-score from baseline to 24 weeks.

RESULTS: Children (n = 251) aged 9-12 years and their primary caregiver were randomized to receive the SWITCH intervention (n = 127) or no intervention (controls; n = 124). There was no significant difference in change of zBMI between the intervention and control groups, although a favorable trend was observed (-0.016; 95% CI: -0.084, 0.051; p = 0.64). There were also no significant differences on secondary outcomes, except for a trend towards increased children's moderate intensity physical activity in the intervention group (24.3 min/d; 95% CI: -0.94, 49.51; p = 0.06).

CONCLUSIONS: A home-based, family-delivered intervention to reduce all leisure-time screen use had no significant effect on screen-time or on BMI at 24 weeks in overweight and obese children aged 9-12 years.

Consumer views on the potential use of mobile phones for the delivery of weight-loss interventions

BACKGROUND: The surge in the incidence of obesity and being overweight demands new options to extend the reach of weight-loss interventions. Mobile phones provide a medium for reaching large numbers of people in a cost-effective manner. The present study aimed to explore the potential for weight-loss interventions to be delivered via mobile phone. METHODS: A mixed methods approach was employed. A telephone survey was conducted with 306 randomly selected participants, and 10 focus groups were undertaken with 54 purposively selected participants. The telephone survey comprised questions exploring the nature and acceptability of any potential weight-loss programme that might be delivered via mobile phones. The focus groups were conducted to explore issues of acceptability in more depth than was possible in the survey. RESULTS: Two-thirds of participants reported support for a mobile phone weight-loss intervention, with greater levels of support amongst younger age groups and rural Māori (the indigenous population in New Zealand). Participants liked the idea of ready access to weight-loss information, and associated feedback and encouragement. The results suggest that interventions would need to include aspects of social support, use tailored and personalised content, and be practical and relevant so that they appeal to consumers. Appropriate methods of providing social support using a mobile phone require further exploration. CONCLUSIONS: Mobile phones may provide a novel but acceptable way to deliver a weight-loss intervention. They have the potential to be automatically personalised and tailored to the needs of the individual, at the same time as being delivered at a population level.