• Modest weight loss of 5–10% of starting weight can lead to significant health benefits.
• Substantial weight loss offers even greater improvements in obesity-related comorbidities.

Health risks associated with overweight and obesity in adults

Body system	Health risk
Cardiovascular	Stroke Coronary heart disease Cardiac failure Hypertension
Endocrine	Type 2 diabetes Polycystic ovary syndrome
Gastrointestinal	Non-alcoholic fatty liver disease Gallbladder disease Pancreatic disease Gastro-oesophageal reflux disease Cancers of the bowel, oesophagus, gall bladder and pancreas
Genitourinary	Chronic kidney disease – glomerulopathy End-stage renal disease Kidney cancer Kidney stones Prostate cancer Stress urinary incontinence (women) Sexual dysfunction (men)
Pulmonary	Obstructive sleep apnoea Obesity hypoventilation syndrome Asthma
Musculoskeletal	Osteoarthritis – especially the knees Spinal disc disorders Lower back pain Disorders of soft tissue structures such as tendons, fascia and cartilage Foot pain Mobility disability (particularly in older adults)
Reproductive health	Menstrual disorders Miscarriage and poor pregnancy outcome Infertility/sub-fertility Breast cancer (postmenopausal women) Endometrial cancer Ovarian cancer
Mental health	Depression Eating disorders – binge eating disorder Reduced health – related quality of life
Adapted with permission from National Health and Medical Research Council. Clinical practice guidelines for the management of overweight and obesity in adults, adolescents and children in Australia. Canberra: NHMRC, 2013

Weight management in general practice

General practitioners are often the first healthcare providers to identify overweight or obesity. Treatment should be individualised with careful consideration given to the severity of the problem and associated complications using the 5As approach for weight management: Ask and Assess, Advise, Assist and Arrange

Establish a therapeutic relationship, communicate and provide care in a way that is person centred, culturally sensitive, non-directive and non-judgemental
Ask and Assess	Standard care		Active management
	BMI <25	BMI 25–29.9	BMI 30–34.9	BMI 35–39.9	BMI >40
	Routinely assess and monitor BMI and waist circumference (WC)	Routinely assess and monitor BMI and WC Discuss if BMI and/or WC increasing Screen for and manage comorbidities	Routinely assess and monitor BMI and WC Discuss health issues Screen for and manage comorbidities Assess other factors related to health risk – Blood pressure – lipid profile – fasting glucose – liver function tests Ask about symptoms of sleep apnoea and depression
Advise	Promote benefits of healthy lifestyle Explain benefits of prevention of weight gain and maintenance of healthy weight		Promote benefits of healthy lifestyle Explain benefits of weight management
Assist			Assist in setting up weight loss program: Advise lifestyle interventions Based on comorbidities, risk factors and weight history, consider adding intensive weight loss interventions (eg. VLEDs, pharmacotherapy, bariatric surgery) Tailor the approach to the individual Refer to multidisciplinary team for specialist treatment recommendations. Suitable patients include : – BMI >40 – BMI >35 with any serious comorbidity – BMI 30–35 with serious comorbidity and a positive weight trajectory
Arrange			Review and monitoring Long term weight management Referral to specialist weight management clinic if indicated

BMI (kg/m2)	Classification	Men WC 94–102 cm Women WC 80–88 cm	Men WC >102 cm Women WC >88 cm
18.5–24.9	Normal weight†	–	–
25–29.9	Overweight	Increased	High
30–34.9	Obese class I	High	Very high
35–39.9	Obese class II	Very high	Very high
≥40.0	Obese class III	Extremely high	Extremely high
* Disease risk for type 2 diabetes, hypertension and cardiovascular disease † Increased WC can also be a marker for increased risk even in persons of normal weight Reproduced from the Scottish Intercollegiate Guidelines Network (SIGN). Management of obesity. A national clinical guideline. Edinburgh: SIGN; Year. (SIGN publication no. 115). [cited 10 July 2013]. Available from URL: www.sign.ac.uk

Lifestyle Interventions as First-Line Treatment

• Lifestyle modification remains first-line therapy for overweight and obesity.
• Best outcomes are achieved when dietary changes, physical activity, and behavioural strategies are combined.
• Follow the Australian Dietary Guidelines (2013).

🥗 Healthy Eating

• Follow Australian Dietary Guidelines (2013) for a balanced, sustainable diet.
• Focus on:
  • Portion control and meal regularity.
  • High intake of vegetables, fruits, legumes, whole grains, and lean proteins.
  • Prefer low glycaemic index carbohydrates.
• Limit:
  • Discretionary foods (e.g., cakes, biscuits, fried foods).
  • Sugary drinks and high-calorie snacks.

🏃‍♀️ Physical Activity Guidelines

• Duration: ≥150 minutes of moderate-intensity aerobic activity per week (e.g., brisk walking, cycling).
• Frequency: Spread over ≥5 days/week.
• Intensity: Moderate (noticeable increase in heart rate/breathing but still able to talk).
• Types:
  • Aerobic + resistance training (2–3 sessions/week).
  • Flexibility and balance exercises for older adults or deconditioned individuals.
• Progression: Begin at comfortable level; increase intensity/duration gradually.

✨ | Fat Intake Recommendations

• Limit saturated fats: Avoid fatty meats, butter, full-fat dairy.
• Avoid trans fats: Found in fried/processed foods, pastries.
• Encourage healthy fats:
  • Nuts, seeds, avocados.
  • Oily fish (e.g., salmon, sardines).

✨ | Behavioural Strategies

• Goal setting: Specific, realistic, measurable short- and long-term goals.
• Self-monitoring:
  • Food diaries, physical activity logs, weight tracking.
• Problem-solving:
  • Identify barriers and develop coping strategies.
• Stimulus control:
  • Modify environment to reduce exposure to cues that trigger overeating.
• Social support:
  • Family/friend involvement, group programs, online communities.

✨ | Psychological Support

• Offer cognitive behavioural therapy (CBT) or other structured psychological interventions if needed.
• Focus on motivation, emotional regulation, and relapse prevention.

✨ | Long-Term Maintenance

• Focus on sustainable lifestyle changes over short-term diets.
• Regular follow-up:
  • Monitor weight, waist circumference, diet, and activity.
• Adaptation:
  • Help patients adjust goals and strategies based on life changes or setbacks.

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Intensive interventions

1. very low energy diets (VLEDs)
2. pharmacotherapy
3. bariatric surgery

Average weight loss of subjects completing a minimum 1 year weight management intervention; based on review of 80 studies (N=26 455; 18 199 completers [69%])

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Very Low Energy Diets (VLEDs)

✨ | Indications

• Recommended for:
  • BMI ≥30 kg/m² (obese).
  • BMI ≥27 kg/m² with obesity-related comorbidities (e.g., type 2 diabetes, hypertension, dyslipidaemia).
• Best used in structured clinical programs with dietitian or GP supervision.

✨ | Effectiveness

• Average weight loss: 18–20% of baseline body weight during intensive phase.
• Health benefits:
  • Improved glycaemic control.
  • Reduction in blood pressure and total cholesterol.
  • May induce remission of type 2 diabetes in selected cases (e.g., DiRECT trial).

✨ | Mechanism of Action

• Meal replacement-based approach:
  • Replace all meals with formulated VLED products (e.g., shakes, bars, soups).
• High-protein, low-carbohydrate content promotes:
  • Fat oxidation and mild ketosis.
  • Hunger suppression and increased satiety.

✨ | Duration and Safety

• Typical duration: 8–12 weeks intensive phase.
• Extended use:
  • Can be cycled intermittently or maintained up to 12 months under close medical supervision.
• Refeeding phase:
  • Gradual reintroduction of food over several weeks to stabilise weight and prevent regain.

✨ | Contraindications

• Not suitable for:
  • Pregnant or breastfeeding women.
  • Children/adolescents.
  • Elderly or frail individuals.
  • Patients with:
    • Psychological disorders (e.g. eating disorders).
    • Alcohol or substance misuse.
    • Porphyria.
    • Recent myocardial infarction or unstable angina.
• Medical clearance recommended prior to initiation.

✨ | Practical Considerations

• Cost:
  • Commercial meal replacements can be expensive and not PBS-subsidised.
• Suitability:
  • Assess motivation, readiness, and ability to comply with a structured program.

✨ | Monitoring and Support

• Ongoing clinical support is essential:
  • Regular weight monitoring.
  • Check for electrolyte imbalances or nutritional deficiencies.
• Practice training:
  • Health professionals should receive education on safe and effective implementation of VLEDs.
  • Use guidelines from reputable sources (e.g. CSIRO Total Wellbeing Diet, NHMRC frameworks).

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Pharmacotherapy

✨ | Quick snapshot – who qualifies?

Population	Initial BMI threshold for pharmacotherapy	Add therapy if comorbidities present
General adult population	≥ 30 kg m⁻²	≥ 27 kg m⁻²
Aboriginal & Torres Strait Islander or most Asian ancestry	≥ 27 kg m⁻²	≥ 25 kg m⁻² racgp.org.au

• Lower trigger (BMI ≥ 25 kg m⁻² with comorbidity) for Aboriginal & Torres Strait Islander or many Asian populations racgp.org.au

Always pair medicines with a structured program of diet, physical activity, sleep optimisation and psychological support.

Stop rule: discontinue or switch if < 5 % total weight loss after 12 weeks on the maximal tolerated dose, or if adverse effects emerge (TGA Product Information).

✨ | June 2025

Drug (brand)	Class / key mechanism	Standard titration*	Mean placebo-adjusted weight loss at ≥ 52 wk	Typical Australian cost†	Common issues / major cautions
Semaglutide 2.4 mg SC weekly (Wegovy®)	Long-acting GLP-1 RA	0.25 mg weekly → increase q4 wk to 2.4 mg	-12 % to -15 % (STEP trials)	≈ A$460 / month (2.4 mg pen)	– GI upset – gall-stones – rare pancreatitis CI – MTC/MEN-2
Tirzepatide 2.5–15 mg SC weekly (Mounjaro®)	Dual GIP/GLP-1 RA	2.5 mg → +2.5 mg q4 wk; max 15 mg	-15 % to -21 % (SURMOUNT-1)	≈ A$285–695 / month (dose-dependent)	Similar GI profile watch gastroparesis CI – pregnancy
Liraglutide 3 mg SC daily (Saxenda®)	Short-acting GLP-1 RA	0.6 mg daily ↑ 0.6 mg weekly to 3 mg	-8 % (SCALE)	≈ A$380 / month	-GI effects – gall-stones daily injections
Naltrexone 8 mg / Bupropion 90 mg (Contrave®)	Opioid-α-MSH & dopaminergic appetite-control	1 tab mane → titrate to 2 tabs bd over 4 wk	-5 % to -8 %	≈ A$250 / month	Nausea, insomnia; CI – uncontrolled HTN – seizure d/o – opioid use
Phentermine 15–40 mg PO mane (Duromine®, Metermine®)	Sympathomimetic appetite suppressant	Start 15 mg; up-titrate; TGA licence ≤ 12 wk	-3 % to -8 % (12 wk)	≈ A$90–170 / month	↑HR/BP insomnia anxiety CI – CVD – arrhythmia – hyper-thyroid, MAOI use – NOT approved in fixed combo with topiramate
Orlistat 120 mg PO tds (Xenical®)	Gastric & pancreatic lipase inhibitor	No titration	-3 % to -8 %	≈ A$136 / month	Steatorrhoea – ADEK deficiency – take ≤ 30 % kcal fat diet CI – chronic malabsorption – cholestasis

*Titrate more slowly if GI intolerance.
†Private prescription; none are PBS-subsidised for obesity.

✨ | Drug profiles in clinical practice

1 Incretin-based therapies

	Liraglutide 3 mg sc daily	Semaglutide 2.4 mg sc weekly	Tirzepatide 5–15 mg sc weekly
Mechanism	GLP-1 receptor agonist	Potent GLP-1 RA	Dual GIP + GLP-1 RA
Dosing pearls	Daily injection escalate weekly	Weekly escalate q4 wk stop-solids ≥ 24 h pre-op	Weekly same peri-op fasting advice
Key evidence	SCALE: – 8 % WL ↓prediabetes progression	STEP-1: – 15 % WL SELECT: ↓20 % MACE	SURMOUNT-1: – 21 % WL 176-wk extension shows durable loss
Common AEs	N/V (40 %), gall-stones	N/V (44 %), gall-stones rare pancreatitis	Similar GI, plus mild alopecia
Cautions	eGFR < 30, pancreatitis	MEN-2/MTC pregnancy severe depression	Same as semaglutide

2 Central appetite & reward modulators

• Naltrexone/Bupropion acts on hypothalamic POMC neurons and mesolimbic reward pathways. Check baseline BP and psychiatric history; avoid with opioids or uncontrolled hypertension.
• Phentermine (schedule 4) provides short-term catecholamine release. Restrict to ≤ 12 weeks, monitor BP/HR each visit and screen for anxiety or substance-use history.
• Combination with topiramate ER is not registered in Australia

3 Gastro-intestinal fat‐absorption blocker

• Orlistat produces malabsorption of ~30 % ingested fat. Advise < 30 % total energy from fat, supplement ADEK vitamins and measure ACR if renal colic.
• Long-term data show durable if modest weight loss and a 37 % reduction in incident T2DM

✨ | Off-label and emerging options

Agent / status	Typical dose	Evidence & caveats
Topiramate (not on ARTG for obesity)	25–100 mg nocte	– 3–5 kg; paraesthesia, cognitive fog, teratogenic; CI glaucoma, stones
SGLT-2 inhibitors / Metformin	Per diabetes PI	2–3 kg loss; use when T2DM present
Setmelanotide (MC4R agonist)	compassionate access	For rare monogenic obesity; awaiting TGA evaluation

✨ | How to choose an agent

1. Map comorbidities – CVD/high CV-risk → prefer semaglutide or tirzepatide; uncontrolled HTN → avoid phentermine; chronic steatorrhoea → avoid orlistat.
2. Balance efficacy vs cost & route – injectable GLP-1/GIP drugs outperform orlistat/contrave but cost more and may be supply-limited.
3. Contraindication screen – pregnancy intent, thyroid C-cell disease, seizure risk, active gall-stone disease, pancreatitis history, opioid use.
4. Shared decision-making – discuss realistic goals (≥ 5–10 % WL yields tangible metabolic benefit), adherence burdens, and the likelihood of indefinite therapy.

✨ | Monitoring & safety

• Baseline: weight, BMI, waist, BP, FBP, lipids, LFTs, eGFR, mental-health screen.
• Review at 4 & 12 weeks then 3-monthly (weight, vitals, AEs).
• GLP-1/GIP agents: educate on peri-operative fasting (clear fluids only; withhold drug on day –2 for daily liraglutide, day –7 for weekly injections)
• Orlistat: 6-monthly fat-soluble vitamins, spot uACR if renal risk.
• Document and proactively manage common AEs (GI, gall-stones, mood change, tachycardia).

✨| Special considerations

• Aboriginal & Torres Strait Islander peoples: discuss lower BMI thresholds, cultural safety and community programs; subsidise dietitian review via CTG PBS scripts.
• Pregnancy & lactation: all agents contraindicated; cease ≥ 8 weeks before conception.
• Adolescents (12–17 y): Wegovy approved; specialist paediatric review mandatory, monitor growth plates.
• Older adults: prioritise sarcopenia risk—pair pharmacotherapy with resistance training and adequate protein.

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Surgery – bariatric

• Criteria for Surgery
  • BMI >40 kg/m2.
  • BMI >35 kg/m2 with one or more obesity-related complications.
• Endorsement by Diabetes Organizations
  • Bariatric-metabolic surgery proposed as a treatment option for T2DM.
  • Recommended for:
    • Individuals with T2DM and BMI ≥40 kg/m2.
    • Individuals with BMI 35–40 kg/m2 with inadequate glycaemic control despite lifestyle and optimal medical therapy.
• Absolute Contraindications
  • Few absolute contraindications include
    • contraindications to general anesthesia
    • serious blood or autoimmune disorders
    • active substance abuse
    • severe untreated psychiatric illness
    • limited life expectancy due to organ failure or malignancy
• Suitable for younger patients at risk of obesity-related complications but caution advised for older patients (>65 years) due to increased postoperative risks.
• Pregnancy Considerations
  • Associated with reduced risks of gestational diabetes but increased risks of pre-term birth and small-for-gestational-age infants.
  • Women of childbearing potential should avoid pregnancy pre-operatively and 12–18 months postoperatively.
  • Close monitoring and nutritional supplementation are essential for pregnant patients post-surgery.
• Patient Commitment
  • Patients must be willing and motivated to adhere to postoperative lifestyle changes, nutritional supplementation, and follow-ups for safety and success

Pre-operative optimisation of obesity-related complications

Obesity-related complication	Pre-operative screening and optimisation	Improvement after weight loss post-surgery
Type 2 diabetes mellitus	Glycated haemoglobin (HbA1c) and fasting glucose to screen for diabetes Aim for good glycaemic control (HbA1c <7%) prior to surgery	Better glycaemic control and a reduced medication burden Diabetes remission in some cases
Cardiovascular disease	Electrocardiogram (ECG) and cardiac risk assessment Referral to cardiology if high cardiovascular risk, presence of cardiac symptoms or abnormal ECG	Reduction of cardiovascular morbidity of >50% (compared to body mass index [BMI] and age matched controls)
Non-alcoholic fatty liver disease	Liver function tests Consider abdominal ultrasound scan if liver function test increased, specifically to detect fibrotic liver disease	Improved liver histological appearance Potential regression of established liver disease
Obstructive sleep apnoea (OSA) and asthma	Screening questionnaire (eg STOP-BANG) to identify those at risk for OSA Refer to sleep specialist if STOP-BANG score ≥3	Significant improvement in apnoea–hypopnoea index Remission of OSA in some cases

Types of Bariatric Surgery

• Gastric Bypass (Roux-en-Y)
  • Involves creating a small pouch from the stomach and connecting it directly to the small intestine.
  • Restricts food intake and reduces absorption of nutrients.
• Sleeve Gastrectomy
  • Involves removing a large portion of the stomach, leaving a smaller sleeve-shaped stomach.
  • Restricts food intake and reduces hunger-inducing hormones.
• Gastric Banding
  • Involves placing an adjustable band around the upper part of the stomach to create a small pouch.
  • Limits food intake by creating a feeling of fullness.
• Biliopancreatic Diversion with Duodenal Switch (BPD/DS)
  • Involves removing a portion of the stomach and rerouting the small intestine to limit absorption.
  • Most complex and effective in terms of weight loss but carries higher risks.

A. Adjustable gastric band = B. Sleeve gastrectomy = C. Roux-en-Y gastric bypass

Complications of Bariatric Surgery

• Immediate Complications
  • Infection
  • Bleeding
  • Blood clots
  • Anesthesia-related complications
• Short-term Complications
  • Dumping syndrome (nausea, vomiting, diarrhea)
  • Nutrient deficiencies (vitamin and mineral deficiencies)
  • Dehydration
  • Gallstones
• Long-term Complications
  • Weight regain
  • Malnutrition
  • Gastrointestinal issues (ulcers, strictures)
  • Hernias
  • Psychological issues (depression, body image concerns)

Adverse events	Presentation	Management
Acute complications
Surgical complications (eg leaks, perforations, obstruction, infection, haemorrhage)	Abdominal pain, tachycardia, breathlessness, drop in haemoglobin	Usually detected during immediate postoperative period and managed by the surgical team Presence of these symptoms should prompt urgent referral back to the surgical team
Hypoglycaemia (usually in patients with pre-existing diabetes)	Sweating, dizziness, headaches, palpitationsLow capillary blood glucose on testing	Fairly common, especially in patients on insulin or insulin secretagogues Stop sulphonylureas, and stop insulin or decrease doseClose self-monitoring of capillary blood glucose
Dumping syndrome	Abdominal pain, diarrhoea, nausea, flushing, palpitations, sweating, agitation, and syncope after meals rich in simple carbohydrates	Dietary modification, with small regular meals containing protein and complex carbohydrates Acarbose may be helpful in some refractory cases
Long-term complications
Iron-deficiency anaemia	Microcytic, hypochromic anaemia, lethargy, anorexia, pallor, hair loss, muscle fatigue	Oral iron supplements, consider intravenous iron for severe deficiency Vitamin C to increase iron absorptionRule out bleeding ulcers, neoplastic disease or diverticular disease
B12 deficiency	Macrocytic anaemia, leukopenia, glossitis, thrombocytopenia, peripheral neuropathy	Vitamin B12 repletion (oral or intramuscular) Prevention – B12 containing multivitamin supplementation Annual serum B12 level evaluation
Thiamine deficiency	Neurological symptoms, Wernicke’s encephalopathy in severe cases	Appropriate postoperative diet, with regular dietitian follow-up Screen for other nutritional deficiencies Thiamine supplementation
Over-restricted gastric band (for patients with adjustable gastric band)	Maladaptive eating, gastro-oesophageal reflux disorder, vomiting, regurgitation, chronic cough, or recurrent aspiration pneumonia	Reduce amount of fluid in gastric band Consider referral to bariatric surgeon for assessment of band position and function
Weight regain	Maximal weight loss usually achieved at one to two years after surgery, with some weight regain thereafter	For patients with laparoscopic adjustable gastric band – evaluation of band, adjust as required Consider adjuncts (eg very low energy diet, pharmacotherapy) Consider referral back to weight management clinic

Monitoring Complications in General Practice

• Regular Follow-up
  • Schedule regular follow-up appointments post-surgery to monitor progress and identify complications early.
  • Medication review –
    • Avoid nonsteroidal anti-inflammatory drugs (https://doi.org/10.1016/j.soard.2022.03.019)
      • prevalence of peptic ulcers was 1.8% in this cohort of 41,380 patients
      • Continuous NSAID-use (>30 days) is a significant risk factor for peptic ulcers after RYGB
      • No increased risk was observed for temporary NSAID-use (<30 days)
    • Adjust antihypertensives, lipid medications as appropriate. These medications should not be discontinued empirically
    • Adjust diabetes medications. Requirement for anti-diabetes medications often decreases, and in many cases, diabetes remission is achieved. Preference for use of agents with favourable weight profile
    • Medications with a narrow therapeutic index (eg warfarin, digoxin, lithium, antiepileptic medications) also require close monitoring and titration because of altered oral drug bioavailability following bariatric–metabolic surgery.
  • Nutritional supplements:
    • Adult multivitamin and multimineral – containing iron, folic acid, thiamine, vitamin B12. Doses: two daily for sleeve gastrectomy or Roux-en-Y gastric bypass; one daily for adjustable gastric band
    • Citrated calcium – elemental calcium 1200–1500 mg/day
    • Vitamin D – titrate to 25-OH vitamin D levels >30 ng/mL. Typical dose required 3000 IU/day
    • Additional iron and vitamin B12 supplementation as required, based on lab results
  • Laboratory assessment:
    • Full blood count, urea and electrolytes, liver function tests, uric acid, glucose, lipids (every 6–12 months)
    • 25-OH vitamin D, iPTH, calcium, albumin, phosphate, B12, folate, iron studies (annually, more frequently if deficiencies identified)
• Gastrointestinal Symptoms
  • Monitor for symptoms such as abdominal pain, nausea, vomiting, or changes in bowel habits, which could indicate complications like ulcers or strictures.
• Weight Management
  • Monitor weight loss progress and watch for signs of weight regain, which may require additional intervention or support.
• Psychological Support
  • Assess for psychological issues such as depression or body image concerns and provide appropriate support or referral to mental health professionals if needed.
• Screening for Long-term Complications
  • Consider screening for long-term complications such as hernias or gallstones through physical examination or imaging studies if symptoms arise.