Quick Facts on Obesity

• The incidence of obesity is rising.  
• In 2004, approximately 23% of adult Canadians were
obese & 36% were overweight.
• Reducing weight by only 5-10% can reduce the risk of
cardiovascular (CV) disease, diabetes & comorbidites.
• There is debate as to whether Body Mass Index (BMI) is
the best risk predictor for obesity as it does not take into
account fat-free mass, or the abdominal fat shown to
contribute to CV risk.  A measurement of waist
circumference or the waist:hip ratio is a better predictor
of metabolically active visceral fat and disease risk.
• “1lb (0.45kg) = 3500 calories”.  Reducing energy intake
or increasing energy expenditure by 500 calories/day will
result in losing about 1lb (½ kg) in one week. 
• 1kg weight loss Ö ~1cm decrease in waist circumference
• Removal of adipose fat tissue via liposuction does not
achieve metabolic benefits of weight loss.

Weight Loss: Other Options.

• For patients with impaired glucose tolerance (IGT),
lifestyle changes decrease the risk of developing
diabetes; however lifestyle may be hard to
maintain. Drugs such as metformin and
acarbose may also be useful for IGT/weight loss.
{Rosiglitazone ↓ progression to diabetes, but ↑HF, edema & wt.}
• Metformin is useful for obese patients with Type
2 diabetes (providing no contraindication) for its
beneficial outcomes and weight loss potential.
• Drugs known to decrease morbidity & mortality in
patients with CV risk should be considered. (e.g.
ASA, antihypertensives and statins).
• Drugs that should not be used for weight loss:
o thyroid hormone: may cause bone loss & arrhythmias
o amphetamines (eg. Adderal)
• New Drug: Rimonibant (Not yet in Canada)
o A cannabinoid (CB1) receptor blocker with favourable
changes in weight (-6kg/1yr 20mg daily) and cardiometabolic
risk factors (↓waist circumference ↓TG; ↑HDL).  Side effects
(e.g. nausea, anxiety, depression), a high drop-out rate >45%
 and lack of clinical outcome trials warrant caution.

Weight Regain With Continued Therapy

• There generally appears to be a trend towards
partial weight regain despite continued therapy.
(e.g. orlistat, XENDOS trial - Figure 1).  This may
be due in part to the natural history of aging.