Two prominent Canadian knowledge brokers aim to influence how primary care clinicians address obesity, through the dissemination of texts: the Canadian Task Force on Preventive Health Care (guideline) and the Canadian Obesity Network (5As). While written for the same clinician and adult patient population, the recommendations differ. This analysis highlights active decisions that produced the difference.Frame analysis of the guideline and 5As texts.The brokers both frame obesity as a chronic and pathological threat to health, at least to a point. The guideline texts frame obesity primarily as a sign of a behavioural problem, discrediting or ignoring many complicating sources of knowledge. In contrast, the 5As frames obesity as complex through diversifying the knowledge foundation embedded in the texts (e.g., including fat-related stigmatisation; health status differences among those classified as obese). Both de-emphasize social and environmental determinants of weight and health.Frames of problems used by brokers are not neutral, nor are decisions about how knowledge is excluded and included. Knowledge brokering, no matter how scientific and systematic, is limited by its frame. Recognizing the limits of each frame supports reflexivity in knowledge brokering and interventions taken to enhance health.