Weighted Mean Differences For Changes Research Articles

Results from a randomised, open-label trial of a multimodal intervention (exercise, nutrition and anti-inflammatory medication) plus standard care versus standard care alone to attenuate cachexia in patients with advanced cancer undergoing chemotherapy.

LBA12007 Background: Cancer cachexia arises from the interaction between the host and the tumour, triggering an inflammatory response that leads to weight and appetite loss, diminished physical activity, reduced treatment efficacy and survival. Combining interventions to address inflammation, weight loss, and physical activity is proposed as an effective strategy. Building on a promising pilot study, we conducted the MENAC (Multimodal Exercise Nutrition Anti-inflammatory Cachexia) trial to comprehensively evaluate this approach in patients with lung and pancreatic cancer undergoing systemic anti-cancer treatment (SACT). Methods: MENAC was an investigator-initiated, multicentre, open label, randomised phase 3 trial conducted at 17 sites in 4 countries. Patients with stage III or IV lung or pancreatic cancer receiving SACT with non-curative intent were randomly assigned (1:1) to a multimodal intervention consisting of nutritional counselling plus fish oil containing oral nutritional supplements, physical exercise [endurance and strength] and non-steroidal anti-inflammatory drugs [NSAIDs]) versus standard care. Randomisation was stratified by country, cancer type and stage. Primary Objective: To assess differences between arms in change in body weight. Secondary Objectives: To assess differences in muscle mass (measured by CT L3 technique) and physical activity (assessed through step counts using ActivPAL activity meter) between arms. Assessments were conducted at basline (pre-randomisation) and at endpoint (after 6 weeks). Results: From May 2015 to February 2022, 212 patients were enrolled (105 to multimodal treatment, 107 standard care). Over 6 weeks, weight stabilised in patients assigned to multimodal treatment compared with those assigned to standard care (mean weight change [SD] 0.05 kg [3.8] vs – 0.99 kg [3.2], respectively) with a mean difference in weight change of -1.04, 95 % CI -2.02 to -0.06, p=0.04. There was no conclusive difference in muscle mass (mean change [SD] -6.5cm2 [ 10.1] vs -6.3cm2 [11.9], p=0.93) or in mean step counts [SD] (-377.7 [2075] vs -458 [1858], p=0.89). There were 28 and 24 reported SAEs in the intervention and control arm respectively, no SUSARs were reported. Conclusions: A multimodal cachexia intervention stabilised weight compared to standard care at six weeks. There was no difference in physical activity or muscle mass between trial arms. Clinical trial information: NCT02330926 .

Weight Loss in Short-Term Interventions for Physical Activity and Nutrition Among Adults With Overweight or Obesity: A Systematic Review and Meta-Analysis.

Reaching, enrolling, and retaining participants in lengthy lifestyle change interventions for weight loss is a major challenge. The objective of our meta-analysis was to investigate whether lifestyle interventions addressing nutrition and physical activity lasting 6 months or less are effective for weight loss. We searched for peer-reviewed studies on lifestyle change interventions of 6 months or less published from 2012 through 2023. Studies were screened based on inclusion criteria, including randomized controlled trials (RCTs) for adults with overweight or obesity. We used a random-effects model to pool the mean difference in weight loss between intervention and control groups. We also performed subgroup analyses by intervention length and control type. Fourteen RCTs were identified and included in our review. Half had interventions lasting less than 13 weeks, and half lasted from 13 to 26 weeks. Seven were delivered remotely, 4 were delivered in person, and 3 used combined methods. The pooled mean difference in weight change was -2.59 kg (95% CI, -3.47 to -1.72). The pooled mean difference measured at the end of the intervention was -2.70 kg (95% CI, -3.69 to -1.71) among interventions lasting less than 13 weeks and -2.40 kg (95% CI, -4.44 to -0.37) among interventions of 13 to 26 weeks. Short-term multicomponent interventions involving physical activity and nutrition can achieve weight loss for adults with overweight or obesity. Offering short-term interventions as alternatives to long-term ones may reach people who otherwise would be unwilling or unable to enroll in or complete longer programs.

A controlled weight loss intervention study among women of Somali background in Norway

BackgroundWomen of Somali background in Norway have a high prevalence of overweight and obesity, compared with women in the general Norwegian population. For lifestyle interventions to be applicable for immigrants to Norway, it is important to culturally tailor interventions in collaboration with relevant communities. The primary outcome was a difference in weight change between the intervention and control groups. MethodsIn this interventional study, Somali women living in one borough of Oslo Municipality in Norway with body mass index (BMI) ≥27.0 kg.m-2 received a co-created, culturally tailored 12-month weight loss intervention consisting of 24 interactive sessions during the first three months, and monthly sessions for the next nine months, compared to a control group. Both groups were measured at baseline and 12 months. ResultsA total of 169 participants were recruited, and 101 participants completed the follow-up. After multiple imputation, the mean difference in weight change adjusted for baseline weight, age, education, employment, marital status, number of children in the household and length of Norwegian residency was -1.6 kg (95 % CI -3.57, 0.43, p = 0.12) in the intervention compared to the control group. ConclusionThis culturally tailored intervention study demonstrated a modest non-significant effect on weight change after 12 months, possibly due to the short intervention duration and COVID-19. Further studies of a longer duration and considering the provision of childcare are needed to understand whether this approach can be transferred to other immigrant groups and genders.Trial registration: The study was registered at clinicaltrials.gov NCT04578067, 2020-09-29.

Changes in weight, body composition and metabolic parameters after switch to dolutegravir/lamivudine compared with continued treatment with dolutegravir/abacavir/lamivudine for virologically suppressed HIV infection (The AVERTAS trial): a randomised, open-label, superiority trial in Copenhagen, Denmark

IntroductionWith longer life expectancy in people living with HIV (PLWH) on antiretroviral therapy, cardiovascular disease (CVD) has become a common cause of mortality among them. Abacavir has been associated with...

Glucagon-like peptide-1 receptor agonists as a disease-modifying therapy for knee osteoarthritis mediated by weight loss: findings from the Shanghai Osteoarthritis Cohort

ObjectiveObesity is a risk factor for knee osteoarthritis (KOA) development and progression. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are indicated for type 2 diabetes mellitus (T2DM) and obesity. However, whether KOA...

Effectiveness of weight management interventions for adults delivered in primary care: systematic review and meta-analysis of randomised controlled trials

ObjectiveTo examine the effectiveness of behavioural weight management interventions for adults with obesity delivered in primary care.DesignSystematic review and meta-analysis of randomised controlled trials.Eligibility criteria for selection of studiesRandomised controlled...

Is a small change approach for weight management effective? A systematic review and meta‐analysis of randomized controlled trials

Traditional weight management interventions typically involve people making large changes to their energy intake and/or expenditure and can be effective in the short term, but weight regain is common. An alternative strategy is a small change approach, which asks people to make small(er) changes to their diet and/or physical activity behaviors (e.g., 100-kcal reduction or increases of 1000 steps/day). This approach may lead to sustained weight management because such energy-deficit goals are easier for people to integrate into their lives and then maintain. This systematic review and meta-analysis of randomized and quasi-randomized controlled trials assessed the effectiveness of a small change approach for weight management; 21 trials were included. In weight gain prevention trials with adults, the mean difference in weight change between groups was -0.7 kg (95% CI -1.0 to -0.4, 95% PI -1.1 to -0.3) at program-end and -0.9 kg (95% CI -1.5 to -0.3, 95% PI -3.1 to 1.3) at last follow-up, favoring small change interventions. A small change approach was not effective for weight loss. Only 2/21 trials had a low risk of bias. Initial evidence supports the effectiveness of a small change approach for weight gain prevention but not weight loss. Further high-quality trials with longer follow-up are required.

Differential associations of the built environment on weight gain by sex and race/ethnicity but not age.

Objective:To explore the built environment (BE) and weight change relationship by age, sex, and racial/ethnic subgroups in adults.Methods:Weight trajectories were estimated using electronic health records for 115,260 insured Kaiser Permanente Washington members age 18–64 years. Member home addresses were geocoded using ArcGIS. Population, residential, and road intersection densities and counts of area supermarkets and fast food restaurants were measured with SmartMaps (800 and 5,000-meter buffers) and categorized into tertiles. Linear mixed-effect models tested whether associations between BE features and weight gain at 1, 3, and 5 years differed by age, sex, and race/ethnicity, adjusting for demographics, baseline weight and residential property values.Results:Denser urban form and greater availability of supermarkets and fast food restaurants were associated with differential weight change across sex and race/ethnicity. At 5 years, the mean difference in weight change comparing the 3rd versus 1st tertile of residential density was significantly different between males (−0.49 kg, 95% CI: −0.68, −0.30) and females (−0.17 kg, 95% CI: −0.33, −0.01) (P-value for interaction = 0.011). Across race/ethnicity, the mean difference in weight change at 5 years for residential density was significantly different among non-Hispanic (NH) Whites (−0.47 kg, 95% CI: −0.61, −0.32), NH Blacks (−0.86 kg, 95% CI: −1.37, −0.36), Hispanics (0.10 kg, 95% CI: −0.46, 0.65), and NH Asians (0.44 kg, 95% CI: 0.10, 0.78) (P-value for interaction < 0.001). These findings were consistent for other BE measures.Conclusion:The relationship between the built environment and weight change differs across demographic groups. Careful consideration of demographic differences in associations of BE and weight trajectories is warranted for investigating etiological mechanisms and guiding intervention development.

Incorporating automated digital interventions into coach-delivered weight loss treatment: A meta-analysis.

Automated digital interventions (ADIs) represent a potentially promising approach to enhance the outcomes of human coach-delivered weight loss interventions. However, the extent to which ADIs provide additive benefit is unclear. This study represents the first systematic review and meta-analysis of the effectiveness of ADIs for improving the outcomes of human coach-delivered weight loss treatment. Electronic database searches were used to identify trials that compared differences in weight change between (a) weight loss interventions that were delivered exclusively by coaches and (b) interventions supplementing this same human coaching with an ADI. Subgroup and moderator analyses examined the influence of intervention duration, duration of human coach contact, presence of tailored coaching, modality of the ADI and demographic variables on ADI effectiveness outcomes. Thirteen studies met inclusion criteria (1,471 participants). Random-effects meta-analysis revealed a mean difference in weight change between conditions of 2.18 kg at postintervention, representing a medium effect size of .54 (95% CI [.13, .95]). Subgroup analyses suggested that lower duration of coach contact was associated with improved additive effectiveness of ADIs. No other subgroup differences were found. Publication bias appeared to be a potential concern, though high levels of heterogeneity and a small number of included studies likely limited the ability to infer its presence. Results support the use of ADIs to augment coach-delivered behavioral weight loss treatment, and also suggest that ADIs have the greatest impact when coaching is relatively low in frequency or duration. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Effect of Behavioral Therapy With In-Clinic or Telephone Group Visits vs In-Clinic Individual Visits on Weight Loss Among Patients With Obesity in Rural Clinical Practice

Rural populations have a higher prevalence of obesity and poor access to weight loss programs. Effective models for treating obesity in rural clinical practice are needed. To compare the Medicare Intensive Behavioral Therapy for Obesity fee-for-service model with 2 alternatives: in-clinic group visits based on a patient-centered medical home model and telephone-based group visits based on a disease management model. Cluster randomized trial conducted in 36 primary care practices in the rural Midwestern US. Inclusion criteria included age 20 to 75 years and body mass index of 30 to 45. Participants were enrolled from February 2016 to October 2017. Final follow-up occurred in December 2019. All participants received a lifestyle intervention focused on diet, physical activity, and behavior change strategies. In the fee-for-service intervention (n = 473), practice-employed clinicians provided 15-minute in-clinic individual visits at a frequency similar to that reimbursed by Medicare (weekly for 1 month, biweekly for 5 months, and monthly thereafter). In the in-clinic group intervention (n = 468), practice-employed clinicians delivered group visits that were weekly for 3 months, biweekly for 3 months, and monthly thereafter. In the telephone group intervention (n = 466), patients received the same intervention as the in-clinic group intervention, but sessions were delivered remotely via conference calls by centralized staff. The primary outcome was weight change at 24 months. A minimum clinically important difference was defined as 2.75 kg. Among 1407 participants (mean age, 54.7 [SD, 11.8] years; baseline body mass index, 36.7 [SD, 4.0]; 1081 [77%] women), 1220 (87%) completed the trial. Mean weight loss at 24 months was -4.4 kg (95% CI, -5.5 to -3.4 kg) in the in-clinic group intervention, -3.9 kg (95% CI, -5.0 to -2.9 kg) in the telephone group intervention, and -2.6 kg (95% CI, -3.6 to -1.5 kg) in the in-clinic individual intervention. Compared with the in-clinic individual intervention, the mean difference in weight change was -1.9 kg (97.5% CI, -3.5 to -0.2 kg; P = .01) for the in-clinic group intervention and -1.4 kg (97.5% CI, -3.0 to 0.3 kg; P = .06) for the telephone group intervention. Among patients with obesity in rural primary care clinics, in-clinic group visits but not telephone-based group visits, compared with in-clinic individual visits, resulted in statistically significantly greater weight loss at 24 months. However, the differences were small in magnitude and of uncertain clinical importance. ClinicalTrials.gov Identifier: NCT02456636.

Abstract 16363: An 18-month Smoking Cessation Intervention Incorporating Pharmacotherapy and Behavioral Counseling Improves Tobacco Abstinence Rates in Adult Smokers With Serious Mental Illness (smi) in Community Mental Health Settings: Results of a Randomized Clinical Trial

Introduction: Tobacco smoking is the largest contributor to markedly elevated CVD and preventable death in persons with SMI. Trials of combined pharmacologic and behavioral treatments improve abstinence rates, but have targeted those ready to quit right away, and evidence-based treatments are rarely used in the community. Weight gain often accompanies abstinence. Our objective was to determine the effectiveness of an 18m smoking cessation pharmacotherapy and behavioral counseling intervention incorporating weight management and physical activity in persons with SMI. Hypothesis: The active intervention is more effective than control in achieving biochemically validated, 7-day point prevalence smoking abstinence at 18m. Methods: We conducted an RCT in 4 community mental health settings in 192 smokers with SMI, stratified by readiness to quit within 30d or in 1 to 6m. The active intervention group was offered 18m of 1 st -line cessation pharmacotherapy, smoking cessation and weight management counseling tailored to readiness to quit, and support for physical activity. Controls received a quit line referral. Results: Mean(SD) age was 49.6(11.7); cigarettes/day 12.1(9.5); BMI 32.0(7.6) kg/m 2 ; 49% were male, 48% African-American, 62% willing to quit in 30d, 95% completed 18m follow-up. At 18m, 27.8% of active group and 6.3% of controls achieved 7d smoking abstinence (p&lt;0.0001); adjusted odds ratio 6.0 (95% CI: 2.3 –15.6; p=0.0002). There was no significant modification of intervention effect on abstinence by readiness to quit. Mean difference in weight change over 18m between active and control was not significant (3.5 lbs, 95% CI: -3.3 –10.3; p=0.32). Conclusions: Offering 18m of evidence-based cessation treatment in the community substantially increased smoking abstinence without significant weight gain in SMI. Implementing best practice guidelines to treat all smokers regardless of readiness to quit should improve CVD health in this high-risk population.

A systematic review with meta-analyses of text message-delivered behaviour change interventions for weight loss and weight loss maintenance.

Short Message Service (SMS)-delivered behaviour change interventions are frequently used to support weight management. This systematic review examines the effectiveness of SMS-delivered behaviour change interventions for weight management. Electronic databases were searched for randomised controlled trials (RCTs) comparing SMS-delivered adult weight management interventions to control groups, published between 1990 and 2018. Weight change was examined using random effects meta-analyses at intervention cessation and postintervention follow-up. Subgroup analyses examined intervention duration, SMS frequency, theory use, SMS interactivity, and SMS tailoring. Fifteen studies met inclusion criteria (2705 participants). For weight loss interventions (n = 12, 1977 participants), the mean difference in weight change was -2.28 kg (95% confidence interval [CI] -3.17 to -1.36 kg). No studies reported postintervention follow-up. For weight loss maintenance interventions (n = 3, 728 participants), the mean difference in weight change was -0.68 kg (95% CI, -1.31 to -0.05 kg), and postintervention follow-up (n = 2, 498 participants) effects were -0.57 kg (95% CI, -1.67 to 0.53 kg). No subgroup differences were found. SMS-delivered behaviour change interventions for weight loss led to significant small to moderate weight loss and weight loss maintenance compared with control groups. Evidence on long-term effects is limited. SMS-delivered behaviour change interventions are a potentially effective and scalable intervention option for obesity treatment.

A self-help diet and physical activity intervention with dietetic support for weight management in men treated for prostate cancer: pilot study of the Prostate Cancer Weight Management (PRO-MAN) randomised controlled trial.

Overweight and obesity may increase risk of disease progression in men with prostate cancer, but there have been few studies of weight loss interventions in this patient group. In this study overweight or obese men treated for prostate cancer were randomised to a self-help diet and activity intervention with telephone-based dietitian support or a wait-list mini-intervention group. The intervention group had an initial group meeting, a supporting letter from their urological consultant, three telephone dietitian consultations at 4-week intervals, a pedometer and access to web-based diet and physical activity resources. At 12 weeks, men in both groups were given digital scales for providing follow-up weight measurements, and the wait-list group received a mini-intervention of the supporting letter, a pedometer and access to the web-based resources. Sixty-two men were randomised; fifty-four completed baseline and 12-week measurements, and fifty-one and twenty-seven provided measurements at 6 and 12 months, respectively. In a repeated-measures model, mean difference in weight change between groups (wait-list mini-intervention minus intervention) at 12 weeks was -2·13 (95 % CI -3·44, -0·82) kg (P = 0·002). At 12 months the corresponding value was -2·43 (95 % CI -4·50, -0·37) kg (P = 0·022). Mean difference in global quality of life score change between groups at 12 weeks was 12·3 (95 % CI 4·93, 19·7) (P = 0·002); at 12 months there were no significant differences between groups. Results suggest the potential of self-help diet and physical activity intervention with trained support for modest but sustained weight loss in this patient group.

The Relationship Between Whole Grain Intake and Body Weight: Results of Meta-analyses of Observational Studies and Randomized Controlled Trials (FS18-07-19)

ObjectivesTo analyze data from observational studies and randomized controlled trials (RCTs) reporting on the relationship between whole grain (WG) intake and weight status. MethodsA systematic literature search was conducted, using Ovid/Medline, to identify observational studies and RCTs assessing WG food intake and weight status in adults. Meta-regression analysis was used to derive pooled estimates from cross-sectional studies, and a meta-analysis with random effects modeling was used to derive pooled estimates from RCTs. Prospective cohort results were assessed qualitatively since differences in methods and outcomes prevented completion of a pooled analysis. ResultsEleven publications (12 studies; 136,834 subjects) were included in the meta-regression analysis of cross-sectional data, 8 publications (9 studies; 973 subjects) were included in the meta-analysis of RCTs, and 6 publications were reviewed for qualitative assessment of prospective cohort data. RCT intervention lengths ranged from 12–16 weeks, and WG intake from foods ranged from 32–215 g/d in the WG intervention groups. Meta-regression of cross-sectional studies indicated a significant, inverse correlation between body mass index (BMI) and intake of WG from food: weighted slope −0.0141 kg/m2 per g/d [95% confidence interval (CI): −0.0207, −0.0077; r = −0.526, P = 0.0001]. Meta-analysis of data from RCTs showed a non-significant pooled standardized effect size of −0.049 kg (95% CI −0.297, 0.199, P = 0.698) for the mean difference in weight change for the WG intervention groups compared with controls. No significant differences were observed for secondary variables, including waist circumference and % body fat. Prospective cohort results generally showed inverse associations between weight change and baseline WG intake and change in WG intake over follow-up periods of 5 to 20 years. ConclusionsHigher WG intake is significantly inversely associated with BMI in observational studies, but results from RCTs do not show an effect of WG intake on change in weight over periods of up to 16 weeks. RCTs with longer intervention periods are needed to further investigate the potential for WG intake to influence body weight and related anthropometrics. Funding SourcesGeneral Mills, Inc., Minneapolis, MN.

The Relationship between Whole Grain Intake and Body Weight: Results of Meta-Analyses of Observational Studies and Randomized Controlled Trials

Results from some observational studies suggest that higher whole grain (WG) intake is associated with lower risk of weight gain. Ovid Medline was used to conduct a literature search for observational studies and randomized controlled trials (RCTs) assessing WG food intake and weight status in adults. A meta-regression analysis of cross-sectional data from 12 observational studies (136,834 subjects) and a meta-analysis of nine RCTs (973 subjects) was conducted; six prospective cohort publications were qualitatively reviewed. Cross-sectional data meta-regression results indicate a significant, inverse correlation between WG intake and body mass index (BMI): weighted slope, −0.0141 kg/m2 per g/day of WG intake (95% confidence interval (CI): −0.0207, −0.0077; r = −0.526, p = 0.0001). Prospective cohort results generally showed inverse associations between WG intake and weight change with typical follow-up periods of five to 20 years. RCT meta-analysis results show a nonsignificant pooled standardized effect size of −0.049 kg (95% CI −0.297, 0.199, p = 0.698) for mean difference in weight change (WG versus control interventions). Higher WG intake is significantly inversely associated with BMI in observational studies but not RCTs up to 16 weeks in length; RCTs with longer intervention periods are warranted.

Effect of low-fat diet interventions versus other diet interventions on long-term weight change in adults: a systematic review and meta-analysis

BackgroundThe effectiveness of low-fat diets for long-term weight loss has been debated for decades, with dozens of randomized trials (RCTs) and recent reviews giving mixed results.MethodsWe conducted a random effects meta-analysis of RCTs to estimate the long-term effect of low-fat vs. higher fat dietary interventions on weight loss. Our search included RCTs conducted in adult populations reporting weight change outcomes at ≥1 year, comparing low-fat with higher fat interventions, published through July 2014. The primary outcome measure was mean difference in weight change between interventions.FindingsFifty-three studies met inclusion criteria representing 68,128 participants. In the setting of weight loss trials, low-carbohydrate interventions led to significantly greater weight loss than low-fat interventions (n comparisons=18; weighted mean difference [WMD]=1.15 kg, 95% CI=0.52 to 1.79; I2=10%). Low-fat did not lead to differences in weight change compared with other moderate fat weight loss interventions (n=19; WMD=0.36, 95% CI=-0.66 to 1.37; I2=82%), and were superior only when compared with “usual diet” (n=8; WMD=-5.41, 95% CI=-7.29 to −3.54; I2=68%). Similarly, non-weight loss trials and weight maintenance trials, for which there were no low-carbohydrate comparisons, had similar effects for low-fat vs moderate fat interventions, and were superior compared with “usual diet”. Weight loss trials achieving a greater difference in fat intake at follow-up significantly favored the higher fat dietary interventions, as indicated by difference of ≥5% of calories from fat (n=18; WMD=1.04, 95% CI=0.06 to 2.03; I2=78%) or by difference in change serum triglycerides of ≥5 mg/dL (n=17; WMD=1.38, 95% CI=0.50 to 2.25; I2=62%).InterpretationThese findings suggest that the long-term effect of low-fat diets on body weight depends on the intensity of intervention in the comparison group. When compared to dietary interventions of similar intensity, evidence from RCTs does not support low-fat diets over other dietary interventions.

Relative Merits of Low-Carbohydrate Versus Low-Fat Diet in Managing Obesity.

Although low-fat diets (LFD) have been the cornerstone of dietary guidelines for weight reduction, low-carbohydrate diets (LCD) continue to gain attention and popularity. Which diet can achieve significant and sustainable weight loss in unclear, however. Our objective in this study was to compare LCDs with LFDs and their impact on weight loss. We performed a MEDLINE/PubMed search for English-language articles of randomized controlled studies conducted with adults who were overweight or obese for at least 6 months for the time period of January 2001-October 2014. Two reviewers independently abstracted data, including participants' characteristics, diet composition and duration, and change in weight from baseline at 6 and 12 months. A total of 17 studies were analyzed. At 6 months, the mean weight loss for participants on an LCD was -1.439 kg (95% confidence interval -2.319 to -0.558) compared with participants on an LFD (P < 0.001). At 12 months, the difference was smaller, -0.769 kg (95% confidence interval -1.361 to -0.178) but remained statistically significant (P < 0.010). The mean difference in the weight loss between the two diets was attenuated over time. Reducing carbohydrate intake may help patients achieve weight loss. The mean difference in weight change between an LCD and an LFD was too small to have a meaningful impact on weight loss. More studies are needed to better elucidate the role of LCDs in weight loss efforts.

Diet or Exercise Interventions vs Combined Behavioral Weight Management Programs: A Systematic Review and Meta-Analysis of Direct Comparisons

Weight loss can reduce the health risks associated with being overweight or obese. However, the most effective method of weight loss remains unclear. Some programs emphasize physical activity, others diet, but existing evidence is mixed as to whether these are more effective individually or in combination. We aimed to examine the clinical effectiveness of combined behavioral weight management programs (BWMPs) targeting weight loss in comparison to single component programs, using within study comparisons. We included randomized controlled trials of combined BWMPs compared with diet-only or physical activity-only programs with at least 12 months of follow-up, conducted in overweight and obese adults (body mass index ≥25). Systematic searches of nine databases were run and two reviewers extracted data independently. Random effects meta-analyses were conducted for mean difference in weight change at 3 to 6 months and 12 to 18 months using a baseline observation carried forward approach for combined BWMPs vs diet-only BWMPs and combined BWMPs vs physical activity-only BWMPs. In total, eight studies were included, representing 1,022 participants, the majority of whom were women. Six studies met the inclusion criteria for combined BWMP vs diet-only. Pooled results showed no significant difference in weight loss from baseline or at 3 to 6 months between the BWMPs and diet-only arms (–0.62 kg; 95% CI –1.67 to 0.44). However, at 12 months, a significantly greater weight-loss was detected in the combined BWMPs (–1.72 kg; 95% CI –2.80 to –0.64). Five studies met the inclusion criteria for combined BWMP vs physical activity-only. Pooled results showed significantly greater weight loss in the combined BWMPs at 3 to 6 months (–5.33 kg; 95% CI –7.61 to –3.04) and 12 to 18 months (–6.29 kg; 95% CI –7.33 to –5.25). Weight loss is similar in the short-term for diet-only and combined BWMPs but in the longer-term weight loss is increased when diet and physical activity are combined. Programs based on physical activity alone are less effective than combined BWMPs in both the short and long term.