Non-surgical Interventions for Weight Loss in Obese Adults
Objective To systematically review and describe currently available approaches to supporting maintenance of weight loss in obese adults and to assess the evidence for the effectiveness of these interventions.
Design Systematic review with meta-analysis.
Data sources Medline, PsycINFO, Embase, and the Cochrane Central Register of Controlled Trials.
Study selection Studies were identified through to January 2014. Randomised trials of interventions to maintain weight loss provided to initially obese adults (aged ≥18) after weight loss of ≥5% body weight with long term (≥12 months) follow-up of weight change (main outcome) were included.
Study appraisal and synthesis Potential studies were screened independently and in duplicate; study characteristics and outcomes were extracted. Meta-analyses were conducted to estimate the effects of interventions on weight loss maintenance with the inverse variance method and a random effects model. Results are presented as mean differences in weight change, with 95% confidence intervals.
Results 45 trials involving 7788 individuals were included. Behavioural interventions focusing on both food intake and physical activity resulted in an average difference of -1.56 kg (95% confidence interval -2.27 to -0.86 kg; 25 comparisons, 2949 participants) in weight regain compared with controls at 12 months. Orlistat combined with behavioural interventions resulted in a -1.80 kg (-2.54 to -1.06; eight comparisons, 1738 participants) difference compared with placebo at 12 months. All orlistat studies reported higher frequencies of adverse gastrointestinal events in the experimental compared with placebo control groups. A dose-response relation for orlistat treatment was found, with 120 mg doses three times a day leading to greater weight loss maintenance (-2.34 kg, -3.03 to -1.65) compared with 60 mg and 30 mg three times a day (-0.70 kg, 95% confidence interval -1.92 to 0.52), P=0.02.
Conclusions Behavioural interventions that deal with both diet and physical activity show small but significant benefits on weight loss maintenance.
Obesity is one of the greatest causes of preventable morbidity and mortality worldwide, with weight loss associated with reductions in risk of morbidity and mortality. Evidence from systematic reviews suggests that long term weight loss through changes in eating and physical activity is possible, even in adults who have already acquired obesity related illness, and effective weight loss programmes are now available. Wardle and colleagues reported that 28% of adults in the United Kingdom claimed to be actively trying to lose weight. In a population survey based in the United States, Nicklas and colleagues found that that 63% of obese participants had attempted to lose weight over the past 12 months, of whom 40% had succeeded in losing ≥5% of their initial weight and 20% had succeeded in losing ≥10%. Though formal behaviour change interventions and self guided efforts at individual behaviour change are successful in inducing weight loss, however, few people manage to maintain these changes in weight over the long term. Weight loss from behavioural interventions typically peaks at around six months into the weight loss attempt, followed by gradual regain of weight in most individuals. As maintenance of the weight loss is crucial to uphold health benefits, understanding how best to support people in sustaining weight loss is paramount to controlling the obesity epidemic and its consequences.
Compared with initiation of weight loss, the evidence base for maintenance of weight loss is in its infancy. A recent systematic review of 13 randomised controlled trials examining effects of “extended care” for weight loss maintenance reported an average 3.2 kg difference in weight regain between extended care and no or minimal additional contact. Other reviews that have examined weight loss maintenance studies confirm the potential of successful maintenance treatment, although there is considerable heterogeneity between studies. Currently available reviews are limited by not using meta-analyses, no separation of studies focused on weight loss or maintenance, the use of restrictive inclusion criteria focusing on specific subsets of non-surgical studies, inclusion of non-randomised trials, or a lack of systematic identification of studies. To date, no comprehensive systematic review of long term effects of non-surgical treatments for maintenance of weight loss tested in randomised controlled trials is available to examine the effects of different treatments in the prevention of weight regain. We describe currently available non-surgical interventions for weight loss maintenance and have synthesised the randomised controlled evidence for the effectiveness of interventions and intervention delivery features.
Abstract and Introduction
Abstract
Objective To systematically review and describe currently available approaches to supporting maintenance of weight loss in obese adults and to assess the evidence for the effectiveness of these interventions.
Design Systematic review with meta-analysis.
Data sources Medline, PsycINFO, Embase, and the Cochrane Central Register of Controlled Trials.
Study selection Studies were identified through to January 2014. Randomised trials of interventions to maintain weight loss provided to initially obese adults (aged ≥18) after weight loss of ≥5% body weight with long term (≥12 months) follow-up of weight change (main outcome) were included.
Study appraisal and synthesis Potential studies were screened independently and in duplicate; study characteristics and outcomes were extracted. Meta-analyses were conducted to estimate the effects of interventions on weight loss maintenance with the inverse variance method and a random effects model. Results are presented as mean differences in weight change, with 95% confidence intervals.
Results 45 trials involving 7788 individuals were included. Behavioural interventions focusing on both food intake and physical activity resulted in an average difference of -1.56 kg (95% confidence interval -2.27 to -0.86 kg; 25 comparisons, 2949 participants) in weight regain compared with controls at 12 months. Orlistat combined with behavioural interventions resulted in a -1.80 kg (-2.54 to -1.06; eight comparisons, 1738 participants) difference compared with placebo at 12 months. All orlistat studies reported higher frequencies of adverse gastrointestinal events in the experimental compared with placebo control groups. A dose-response relation for orlistat treatment was found, with 120 mg doses three times a day leading to greater weight loss maintenance (-2.34 kg, -3.03 to -1.65) compared with 60 mg and 30 mg three times a day (-0.70 kg, 95% confidence interval -1.92 to 0.52), P=0.02.
Conclusions Behavioural interventions that deal with both diet and physical activity show small but significant benefits on weight loss maintenance.
Introduction
Obesity is one of the greatest causes of preventable morbidity and mortality worldwide, with weight loss associated with reductions in risk of morbidity and mortality. Evidence from systematic reviews suggests that long term weight loss through changes in eating and physical activity is possible, even in adults who have already acquired obesity related illness, and effective weight loss programmes are now available. Wardle and colleagues reported that 28% of adults in the United Kingdom claimed to be actively trying to lose weight. In a population survey based in the United States, Nicklas and colleagues found that that 63% of obese participants had attempted to lose weight over the past 12 months, of whom 40% had succeeded in losing ≥5% of their initial weight and 20% had succeeded in losing ≥10%. Though formal behaviour change interventions and self guided efforts at individual behaviour change are successful in inducing weight loss, however, few people manage to maintain these changes in weight over the long term. Weight loss from behavioural interventions typically peaks at around six months into the weight loss attempt, followed by gradual regain of weight in most individuals. As maintenance of the weight loss is crucial to uphold health benefits, understanding how best to support people in sustaining weight loss is paramount to controlling the obesity epidemic and its consequences.
Compared with initiation of weight loss, the evidence base for maintenance of weight loss is in its infancy. A recent systematic review of 13 randomised controlled trials examining effects of “extended care” for weight loss maintenance reported an average 3.2 kg difference in weight regain between extended care and no or minimal additional contact. Other reviews that have examined weight loss maintenance studies confirm the potential of successful maintenance treatment, although there is considerable heterogeneity between studies. Currently available reviews are limited by not using meta-analyses, no separation of studies focused on weight loss or maintenance, the use of restrictive inclusion criteria focusing on specific subsets of non-surgical studies, inclusion of non-randomised trials, or a lack of systematic identification of studies. To date, no comprehensive systematic review of long term effects of non-surgical treatments for maintenance of weight loss tested in randomised controlled trials is available to examine the effects of different treatments in the prevention of weight regain. We describe currently available non-surgical interventions for weight loss maintenance and have synthesised the randomised controlled evidence for the effectiveness of interventions and intervention delivery features.
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