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The WHO definition of obesity is an abnormal or excessive accumulation of body fat that may impair health. The outstanding cause of weight gain in exogenous obesity is excessive calorie intake coupled with lack of exercise. Useful measuring instruments include:


  • body mass index (BMI): ‘healthy’ range is between 20 and 25 (BMI = weight (kg) ÷ height (m2))

  • abdominal fatness—defined as a waist:hip circumference ratio (W/H ratio) of >0.85 in women and >0.95 in men—which is a better predictor of cardiovascular risk and other complications of obesity than BMI

  • waist circumference: risk of comorbidity ♂ >94 cm; ♀ >80 cm

  • single skin-fold thickness (>25 mm suggests increased body fat)

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Classification of obesity

++ Management principles

  1. Reduction in energy intake

  2. Change in diet composition

  3. Increased physical activity, (e.g. walking 30 min/d or 10 000 steps/d (use pedometer))

  4. Behavioural therapy

++ Rules

  • Need a close supportive relationship.

  • Promote realistic goals—lose weight slowly.

  • Follow a low-fat, high-fibre, reduced calorie intake diet.

  • Allow normal foods with reduced quantity and frequency (e.g. eat ⅓ less than usual).

  • Supportive counselling (never judgmental).

  • Provide a list of ‘tips’ for coping.

  • Advise keep a food, exercise and behaviour diary.

  • Strict follow-up (e.g. fortnightly, then monthly) until goal weight achieved, then 3 mthly reviews.

++ Pharmacotherapy (adjunct therapy)

Adverse effects can be problematic. Consider for those with BMI >30 and failed well-supervised lifestyle measures.


The agents are:


  • local, acting on GIT:

    • bulking agents (e.g. methylcellulose)

    • lipase inhibitors—orlistat (Xenical) 120 mg (o) tds ac (used with a low-fat eating program)

  • centrally acting agents:

    • amphetamine derivatives (reduce hunger)

    • phentermine 15–40 mg (o)/d (limited use)

  • serotonin analogues (enhances satiety)

    • fluoxetine 20–40 mg (o)/d

    • sibutramine 10–15 mg (o)/d (monitor BP)

    • sertraline 50–100 mg (o)/d

++ Bariatric surgery

Consider surgical intervention (e.g. Lap Band, sleeve gastrectomy and Roux-en-Y bypass)—perhaps the most effective treatment for obesity. It is recommended in those with a BMI >40 or >35 with severe comorbidities, especially diabetes.


Obsessive–compulsive disorder


  • Psychological intervention, esp. cognitive behaviour therapy

  • Refer for group therapy

  • Any SSRI antidepressant (e.g. fluoxetine 20 mg (o)/d) is first-line pharmacological treatment

  • Second line: clomipramine 50–75 mg (o) nocte, increasing every 2–3 d to 100–250 mg orally (o) nocte


Obstetric care


Basic antenatal care


Antenatal care presents ...

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