Levels of evidence
| LEVEL OF EVIDENCE | FEATURES | OUTCOME CONSIDERED | COMMENTS |
|---|---|---|---|
| Level I | At least 1 properly conducted RCT, systematic review, or meta-analysis | Mortality | 2 good meta-analyses, 2 systematic reviews, 2 reviews of prospective cohort studies |
| Morbidity (HRQOL) | Numerous RCTs and prospective clinical trials | ||
| Interventions in weight trajectory | One meta-analysis, several RCTs, numerous traditional reviews | ||
| Level II | Other comparison trials; non-randomized, cohort, case-control, or epidemiologic studies; and preferably more than 1 study | Population weight metrics | Primarily population-based longitudinal, prospective cohort, and cross-sectional studies |
| Level III | Expert opinion or consensus statements | NA | NA |
HRQOL—health-related quality of life, NA—not applicable, RCT—randomized controlled trial.