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Obesity and Health Practices · Journal article
JAMA Network Open · August 11, 2026
Encouraging direction, but not yet definitive.
This open-label randomized trial of 200 adults with obesity in Brazil found that a 20-week hybrid lifestyle intervention combined with usual care did not significantly increase the proportion achieving ≥5% weight loss compared to usual care alone in intention-to-treat analysis. Per-protocol and secondary analyses suggested cardiometabolic improvements among those who adhered to the program, but the primary outcome was not met, and substantial differential dropout limits confidence in these secondary findings.
Open-label, parallel-group, superiority randomized controlled trial. Adults with body mass index ≥30 recruited from a tertiary public hospital in São Paulo, Brazil. Participants had mean age 47.9 (SD 14.0) years; 86% (172/200) were women.. Intervention: PRAMEV: 20-week hybrid lifestyle intervention including group-based behavioral counseling, nutritional education, physical activity promotion, and continuous instructor support. Compared with: Usual medical care. n = 200. Tertiary public hospital in São Paulo, Brazil.
Primary outcome (≥5% weight loss): 20.6% (20/97) in PRAMEV vs 15.5% (16/103) in control; OR 1.34 (95% CI 0.61–2.92), P=0.46 (not significant) Dropout rate higher in PRAMEV (39.2%, 38/97) than control (21.4%, 22/103), P=0.008 Per-protocol analyses showed greater weight loss and improved anthropometric outcomes in PRAMEV arm
No serious adverse events reported
Clinicians should interpret this as evidence that a 20-week hybrid lifestyle program did not outperform usual care alone for achieving meaningful weight loss at the population level. However, the per-protocol benefits in metabolic markers (lipid profile, liver enzymes, triglycerides) among participants who completed the program merit further investigation in larger, longer-term studies with strategies to improve adherence.
A randomized trial of reasonable design that failed its primary endpoint in intention-to-treat analysis but showed metabolic benefits in per-protocol subgroups; results suggest potential in adherent participants but require confirmation in larger, longer studies.
As stated by the source record.
Quoted from the source exactly as published.
Clinicians should interpret this as evidence that a 20-week hybrid lifestyle program did not outperform usual care alone for achieving meaningful weight loss at the population level. However, the per-protocol benefits in metabolic markers (lipid profile, liver enzymes, triglycerides) among participants who completed the program merit further investigation in larger, longer-term studies with strategies to improve adherence.
Graded across the dimensions that decide whether you should act, each from what the source actually supports. There is no single score, and where a dimension was not assessed it says so.
Importance: Obesity disproportionately affects low- and middle-income countries, where access to structured, scalable treatment remains limited. Objective: To evaluate whether a hybrid-format, intensive lifestyle modification program combined with usual medical care promotes a minimum weight loss of 5% in adults with obesity compared with usual medical care alone. Design, Setting, and Participants: This open-label, parallel-group, superiority randomized clinical trial recruited adults with a body mass index of 30 or greater from a tertiary public hospital in São Paulo, Brazil, between January 1 and March 31, 2022, randomized 1:1 to PRAMEV (Advanced Program for Intensive Lifestyle Modification) or control. Data were analyzed from May to September 2025 using an intention-to-treat approach. Interventions: PRAMEV was a 20-week, hybrid lifestyle intervention that included group-based behavioral counseling, nutritional education, physical activity promotion, and continuous instructor support. The control group received usual medical care. Main Outcomes and Measures: The primary outcome was the proportion of participants achieving a 5% or greater reduction in body weight assessed by bioelectrical impedance analysis at 20 weeks. Secondary outcomes included changes in weight, body mass index, waist circumference, metabolic parameters (lipid profile, glucose, and liver enzyme levels), dietary intake, and psychosocial variables. Results: A total of 200 participants (mean [SD] age, 47.9 [14.0] years; 172 [86.0%] women) were randomized to PRAMEV (n = 97) or control (n = 103). At 20 weeks, 143 participants (71.4%) completed follow-up, with higher dropout in the PRAMEV arm vs the control arm (39.2% [38 of 97] vs 21.4% [22 of 103]; P =.008). In the intention-to-treat analysis, groups did not differ in achieving 5% or greater weight loss (20.6% [20 of 97] vs 15.5% [16 of 103]; odds ratio, 1.34; 95% CI, 0.61-2.92; P =.46). Per-protocol analyses showed greater weight loss and improved anthropometric outcomes in the PRAMEV arm. The intervention improved the lipid profile, with reductions in liver enzyme and triglyceride levels and favorable changes in cholesterol fractions. No serious adverse events were reported. Conclusions and Relevance: In this randomized clinical trial of 200 adults with obesity receiving care in Brazil's public health care system, a hybrid-format lifestyle intervention did not improve the likelihood of achieving 5% or greater weight loss in the intention-to-treat analysis. However, secondary and per-protocol analyses suggested potential cardiometabolic benefits among adherent participants, warranting further investigation. Trial Registration: ReBEC Identifier: U1111-1273-8313.
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