These recommendations apply to apparently healthy adults ≥ 18 years of age who present to primary care. These recommendations do not apply to people with eating disorders, or who are pregnant. The management guidelines do not apply to those with body mass index measurements greater than 40, who may benefit from specialized bariatric programs.
BURDEN OF ILLNESS
Over two thirds of Canadian men (67%) and more than half of Canadian women (54%) are overweight or obese. Excess weight is a well-recognized risk factor for many chronic conditions.
Formal structured behavioural and lifestyle interventions and pharmacological interventions
- We recommend measuring height, weight and calculating BMI at appropriate primary care visits. (Strong recommendation; very low quality evidence)
- We recommend that practitioners not offer formal, structured interventions aimed at preventing weight gain in normal weight adults. (Weak recommendation; very low quality evidence)
- For adults who are obese (30 ≤ BMI < 40) and are at high risk of diabetes, we recommend that practitioners offer or refer to structured behavioural interventions aimed at weight loss. (Strong recommendation; moderate quality evidence)
- For adults who are overweight or obese, we recommend that practitioners offer or refer to structured behavioural interventions aimed at weight loss. (Weak recommendation; moderate quality evidence)
- For adults who are overweight or obese, we recommend that practitioners not routinely offer pharmacologic interventions (orlistat or metformin) aimed at weight loss. (Weak recommendation; moderate quality evidence)
BASIS OF RECOMMENDATIONS
- BMI is easy and inexpensive to measure, and can be used to monitor weight changes over time.
- Interventions for prevention of weight gain in adults of normal weight have a minimal effect and the effect is not sustained over time.
- Weight loss interventions (behavioural and/or pharmacological) are effective in modestly reducing weight and waist circumference.
- While most participants in weight loss studies regain some weight after intervention, the average amount regained is lower among intervention participants than control participants.
- For adults who are at risk of developing type 2 diabetes, weight loss interventions delay the onset of type 2 diabetes.
- Behavioural interventions are the preferred option, as the benefit to harm ratio appears more favourable than for pharmacological interventions.
DETAILS OF RECOMMENDED SERVICES
Formal structured behavioural and lifestyle interventions
Behavioural modification programs that involve several sessions or interactions that take place over weeks to months. Behaviourally-based interventions may focus on diet, increasing exercise, making lifestyle changes, or any combination of these. Lifestyle interventions generally included counselling, education or support, and/or environmental changes in addition to changes in exercise and/or diet.
The use of metformin and orlistat for weight loss.
CONSIDERATIONS FOR IMPLEMENTATION
Interventions could be offered in primary care settings or settings where primary care practitioners may refer patients, such as credible commercial or community programs. The most effective interventions were highly heterogeneous with respect to provider discipline, length and format. Therefore, a specific program cannot be recommended, however interventions are likely appropriate for patients ready and able to make substantive lifestyle changes. Practitioners should be aware of barriers to participation in weight loss interventions.