Is obesity a medical condition or a lifestyle choice?

Obesity is recognised as a chronic relapsing disease by the World Health Organization and Australian medical bodies. Set-point biology is the key driver — after weight loss, the body compensates by increasing the hunger hormone ghrelin and reducing leptin (the fullness signal), pushing weight back toward the original set-point. This is why most people who lose weight through diet alone regain it over two to five years. Effective treatment requires medical intervention alongside lifestyle change, just as it does for hypertension or type 2 diabetes. Reducing weight stigma in clinical care is an explicit priority in the National Obesity Strategy 2022–2032.

What is metabolic syndrome and why does it matter?

Metabolic syndrome is a cluster of features that together significantly raise cardiovascular and type 2 diabetes risk. The NCEP-ATPIII criteria require central obesity (waist ≥94 cm men / ≥80 cm women for Caucasian; ≥90 cm / ≥80 cm for South Asian and East Asian) plus at least two of: triglycerides ≥1.7 mmol/L, HDL <1.0 (men) or <1.3 (women) mmol/L, blood pressure ≥130/85 mmHg, and fasting glucose ≥5.6 mmol/L. Each component multiplies cardiovascular risk; having all five roughly doubles the lifetime risk of heart disease and quintuples the risk of developing type 2 diabetes. Treating metabolic syndrome means treating all five components, not just weight.

Are medications like Ozempic or Mounjaro available on the PBS for weight loss?

No, as of mid-2026 no GLP-1 receptor agonist is PBS-subsidised specifically for weight management or obesity in Australia. Semaglutide 2.4 mg (Wegovy) and tirzepatide (Mounjaro) are TGA-approved for obesity but both carry private costs — typically AU$300–450 per month. Semaglutide 1 mg (Ozempic) and oral semaglutide (Rybelsus) remain PBS Authority-required for type 2 diabetes only. Tirzepatide had a PBAC recommendation for T2DM in early 2026 but Lilly declined the listing terms in April 2026, so it is currently private prescription only for any indication. Weight regain is common on cessation — these are chronic-disease medications, not short-course treatments.

When is bariatric surgery considered?

Australian guidelines support bariatric surgery when BMI is ≥40 kg/m², or ≥35 with significant comorbidity such as type 2 diabetes, obstructive sleep apnoea, or severe joint disease. Some specialist centres consider surgery from BMI ≥30 when type 2 diabetes is present and poorly controlled. The two most common procedures in Australia are sleeve gastrectomy (~25–30% total weight loss) and Roux-en-Y gastric bypass (~30–35% total weight loss, with high rates of type 2 diabetes remission). Both require multidisciplinary assessment pre-operatively and lifetime nutritional monitoring post-operatively. Private costs are typically AU$15,000–25,000; public access is limited and varies by state.

What diet is best for weight loss in obesity?

No single dietary pattern has been shown to be superior for long-term weight management in high-quality Australian trials; adherence and sustainability matter more than the specific pattern. The Mediterranean diet has the strongest cardiovascular outcome evidence, including in people with obesity. Low-carbohydrate and ketogenic diets produce comparable short-term weight loss to low-fat diets but show variable long-term adherence. Intermittent fasting (including 16:8 time-restricted eating) is another reasonable option with emerging evidence. A very low-calorie diet (VLCD, ~800 kcal/day for ≤12 weeks) under medical supervision can achieve type 2 diabetes remission in early disease — the DiRECT trial showed 46% remission at 12 months. Discuss options with a dietitian who can tailor the approach to preferences, culture, and comorbidities.

What are the risks of GLP-1 medications I should know about?

The most common side effect of GLP-1 receptor agonists and tirzepatide is nausea, which is managed by slow dose titration over four to eight weeks. More serious but rare effects include gallstone formation and acute pancreatitis. Gastroparesis (slowing of gastric emptying) is relevant to anaesthesia — current guidance recommends ceasing GLP-1 RA at least one week before elective surgery to reduce aspiration risk. Tirzepatide has a specific TGA December 2024 safety update: it may reduce the effectiveness of oral contraceptive pills, so non-oral or barrier contraception is recommended at initiation and for four weeks after each dose increase. These medications are contraindicated in personal or family history of medullary thyroid cancer or MEN-2 syndrome.

Obesity and metabolic syndrome

Obesity and metabolic syndrome: the AU general practice approach

Q: Are medications like Ozempic or Mounjaro available on the PBS for weight loss?

No, as of mid-2026 no GLP-1 receptor agonist is PBS-subsidised specifically for weight management or obesity in Australia. Semaglutide 2.4 mg (Wegovy) and tirzepatide (Mounjaro) are TGA-approved for obesity but both carry private costs — typically AU$300–450 per month. Semaglutide 1 mg (Ozempic) and oral semaglutide (Rybelsus) remain PBS Authority-required for type 2 diabetes only. Tirzepatide had a PBAC recommendation for T2DM in early 2026 but Lilly declined the listing terms in April 2026, so it is currently private prescription only for any indication. Weight regain is common on cessation — these are chronic-disease medications, not short-course treatments.

Q: When is bariatric surgery considered?

Australian guidelines support bariatric surgery when BMI is ≥40 kg/m², or ≥35 with significant comorbidity such as type 2 diabetes, obstructive sleep apnoea, or severe joint disease. Some specialist centres consider surgery from BMI ≥30 when type 2 diabetes is present and poorly controlled. The two most common procedures in Australia are sleeve gastrectomy (~25–30% total weight loss) and Roux-en-Y gastric bypass (~30–35% total weight loss, with high rates of type 2 diabetes remission). Both require multidisciplinary assessment pre-operatively and lifetime nutritional monitoring post-operatively. Private costs are typically AU$15,000–25,000; public access is limited and varies by state.

Q: What diet is best for weight loss in obesity?

No single dietary pattern has been shown to be superior for long-term weight management in high-quality Australian trials; adherence and sustainability matter more than the specific pattern. The Mediterranean diet has the strongest cardiovascular outcome evidence, including in people with obesity. Low-carbohydrate and ketogenic diets produce comparable short-term weight loss to low-fat diets but show variable long-term adherence. Intermittent fasting (including 16:8 time-restricted eating) is another reasonable option with emerging evidence. A very low-calorie diet (VLCD, ~800 kcal/day for ≤12 weeks) under medical supervision can achieve type 2 diabetes remission in early disease — the DiRECT trial showed 46% remission at 12 months. Discuss options with a dietitian who can tailor the approach to preferences, culture, and comorbidities.

Q: What are the risks of GLP-1 medications I should know about?

The most common side effect of GLP-1 receptor agonists and tirzepatide is nausea, which is managed by slow dose titration over four to eight weeks. More serious but rare effects include gallstone formation and acute pancreatitis. Gastroparesis (slowing of gastric emptying) is relevant to anaesthesia — current guidance recommends ceasing GLP-1 RA at least one week before elective surgery to reduce aspiration risk. Tirzepatide has a specific TGA December 2024 safety update: it may reduce the effectiveness of oral contraceptive pills, so non-oral or barrier contraception is recommended at initiation and for four weeks after each dose increase. These medications are contraindicated in personal or family history of medullary thyroid cancer or MEN-2 syndrome.

By Dr HB Lo, FACRRM Reviewed 28 May 2026 10 min read

Obesity (~31% of AU adults) is a chronic relapsing disease driven by set-point biology, not willpower. Metabolic syndrome = central obesity plus ≥2 of: raised triglycerides, low HDL, elevated BP, raised fasting glucose.

Comprehensive lifestyle intervention is first-line: Mediterranean diet, ≥150 min/week aerobic exercise, resistance training, and behavioural support. GLP-1 receptor agonists (semaglutide, tirzepatide) achieve 10–25% weight loss but are not PBS-subsidised for obesity in Australia.

Bariatric surgery (BMI ≥40 or ≥35 with comorbidity) offers durable weight loss and T2DM remission. Active management of comorbidities — type 2 diabetes, hypertension, dyslipidaemia — is essential.

Obesity is the most common chronic disease in Australia. Roughly two-thirds of Australian adults are overweight or obese, with about 31% classified as obese, according to AIHW surveillance data. Its consequences are not limited to excess body weight: obesity drives type 2 diabetes, cardiovascular disease, obstructive sleep apnoea, non-alcoholic fatty liver disease, several cancers, and a substantial burden on quality of life and functional capacity.

The key conceptual shift in modern obesity medicine — and the one that matters most in clinical conversations — is reframing obesity as a chronic relapsing disease, not a personal failure. Set-point biology explains why: after weight loss, ghrelin rises and leptin falls, creating a persistent drive to regain weight that most patients cannot overcome through willpower alone. This has implications for both the choice of treatment and how long treatment needs to continue.

A. Core clinical — the AU general-practice framework

Definitions and classification

BMI classification per NHMRC guidelines:

Overweight: BMI 25–29.9 kg/m²
Obesity class I: BMI 30–34.9
Obesity class II: BMI 35–39.9
Obesity class III (severe): BMI ≥40

Asian-specific cutoffs are lower: overweight ≥23, obesity ≥25–27.5 kg/m² for South Asian, Chinese, and other East Asian populations. BMI alone misclassifies central adiposity in these groups — always measure waist.

Waist circumference is often a more clinically relevant predictor of cardiometabolic risk than BMI. Risk thresholds: Caucasian ≥94 cm men / ≥80 cm women; South Asian and Chinese ≥90 cm / ≥80 cm.

Metabolic syndrome (NCEP-ATPIII / IDF criteria) = central obesity plus ≥2 of:

Triglycerides ≥1.7 mmol/L
HDL under 1.0 mmol/L (men) / under 1.3 mmol/L (women)
Blood pressure ≥130/85 mmHg
Fasting glucose ≥5.6 mmol/L

Clinical assessment

History — weight trajectory (peak, prior interventions, what worked and why it stopped); dietary pattern and timing; eating behaviours including emotional eating, binge eating, night eating; physical activity and sedentary time; sleep duration, snoring, witnessed apnoeas; mood, anxiety, body image; medications that drive weight gain (antipsychotics — olanzapine and clozapine highest risk; corticosteroids, antiepileptics, some antidepressants, insulin); family history of obesity, type 2 diabetes, and cardiovascular disease.

Screening for secondary causes deserves a routine check: hypothyroidism (TSH), Cushing’s syndrome (especially with central fat distribution, thin skin, striae — 1 mg dexamethasone suppression test), PCOS in women, and hypothalamic causes in those with relevant neurological history.

Screen for binge eating disorder (BED) — it is present in approximately 15–25% of patients presenting for obesity treatment, frequently undiagnosed, and predicts poor response to standard weight management without concurrent psychological support.

Investigations per eTG Endocrinology and NHMRC guidelines:

HbA1c and/or fasting glucose
Fasting lipid profile
UEC, eGFR, and urine albumin-creatinine ratio (UACR) — kidney function and early diabetic nephropathy
LFTs — assess for non-alcoholic fatty liver disease (NAFLD); if elevated, calculate FIB-4 score; refer for ultrasound or FibroScan if FIB-4 >2.67
TSH
Vitamin D, B12, ferritin, FBC
ECG pre-pharmacotherapy where indicated
OSA screening: Epworth Sleepiness Scale, STOP-BANG questionnaire; proceed to sleep study if positive

Heart Foundation 2023 cardiovascular risk calculation should be performed — it guides lipid and antihypertensive treatment thresholds alongside weight management.

Treatment hierarchy

Per RACGP, NHMRC, and eTG:

Comprehensive lifestyle intervention — dietary change, physical activity, behavioural support, sleep and OSA management
Pharmacotherapy — adjunct to lifestyle when BMI ≥30, or ≥27 with comorbidity
Bariatric surgery — for BMI ≥40 or ≥35 with significant comorbidity

Parallel management of comorbidities (type 2 diabetes, hypertension, dyslipidaemia, OSA) is integrated throughout — not deferred until weight targets are achieved.

B. Pharmacotherapy for obesity in Australia

GLP-1 receptor agonists and tirzepatide

The GLP-1 receptor agonist class — and the newer dual GIP/GLP-1 receptor agonist tirzepatide — has transformed weight management pharmacotherapy by countering set-point biology through amplifying satiety signals in the hypothalamus and slowing gastric emptying.

Semaglutide 2.4 mg weekly subcutaneous (Wegovy) — TGA-approved in Australia for chronic weight management since 2022. The STEP 1 trial (NEJM 2021) demonstrated ~15% mean weight loss at 68 weeks in adults with obesity without type 2 diabetes. Not PBS-listed for obesity — private cost approximately AU$300–350/month.

Tirzepatide (Mounjaro) — dual GIP/GLP-1 receptor agonist TGA-approved in Australia for type 2 diabetes, chronic weight management, and obstructive sleep apnoea in obesity. The SURMOUNT-1 trial (NEJM 2022) showed 15–25% mean weight loss depending on dose, with 37% of participants at the highest dose (15 mg weekly) achieving ≥25% weight loss. A PBAC recommendation for PBS listing in type 2 diabetes was issued in early 2026, but Lilly declined the listing terms in April 2026 — tirzepatide remains a private prescription for all indications at approximately AU$400+/month.

Semaglutide 1 mg weekly (Ozempic) and oral semaglutide (Rybelsus) — PBS Authority Required for type 2 diabetes with specific criteria; off-label for obesity management.

Patients need to understand that weight regain after stopping these medications is common and often substantial — this is a chronic-disease model requiring ongoing treatment, not a short course.

Counselling for GLP-1 RA and tirzepatide per AMH and TGA guidance:

Nausea is the most common adverse effect — titrate slowly over 4–8 weeks; take with food, avoid high-fat meals
Rare but serious: gallstone formation, acute pancreatitis
Pre-anaesthetic cessation: cease at least one week before elective surgery — gastroparesis increases aspiration risk under anaesthesia (2023 anaesthetic guidance)
Tirzepatide and contraception: oral contraceptive pill efficacy may be reduced; recommend non-oral or barrier contraception at initiation and for four weeks after each dose increase (TGA December 2024 update)
Contraindicated in personal or family history of medullary thyroid carcinoma or MEN-2
Cease at least two months before planned conception; limited safety data in pregnancy

Other approved pharmacotherapy options

Per eTG and AMH:

Agent	Weight loss	Notes
Orlistat 120 mg TDS	~3–5%	Pancreatic lipase inhibitor; available OTC; steatorrhoea common; fat-soluble vitamin deficiency
Phentermine (Duromine) 15–30 mg	~5–7%	Sympathomimetic; Schedule 4; maximum 12 weeks; cardiovascular and psychiatric cautions
Naltrexone-bupropion (Contrave)	~5–7%	Not PBS-listed for obesity; private prescription; lower seizure threshold

Advise patients against compounded or “off-brand” GLP-1 products — TGA has ongoing enforcement action against compounders; quality and dosing consistency are not assured.

C. Bariatric and metabolic surgery

Bariatric surgery is the most durable weight loss intervention available. The STAMPEDE trial (NEJM 2017) demonstrated that surgery significantly outperformed intensive medical therapy for both weight loss and type 2 diabetes control at five years.

Indications per NHMRC guidelines:

BMI ≥40 kg/m²
BMI ≥35 with significant comorbidity (type 2 diabetes, obstructive sleep apnoea, severe NAFLD, severe osteoarthritis, refractory hypertension)
BMI ≥30 with poorly controlled type 2 diabetes — considered in some specialist metabolic surgery programmes

Procedures commonly performed in Australia:

Sleeve gastrectomy — most common (~60–65% of AU bariatric procedures); ~25–30% total weight loss; restrictive mechanism; higher rates of de novo gastro-oesophageal reflux post-procedure.

Roux-en-Y gastric bypass (RYGB) — ~30–35% total weight loss; combined restrictive and malabsorptive mechanism; highest rates of type 2 diabetes remission; risk of dumping syndrome and reactive hypoglycaemia.

Adjustable gastric banding — declining in AU; less effective and more complications with long-term follow-up.

Pre-operative requirements: multidisciplinary assessment (surgeon, dietitian, psychologist, anaesthetist); OSA identification and treatment; baseline vitamin and mineral status; psychological readiness screen; abstinence from smoking.

Post-operative monitoring — lifetime requirement: B12 (deficiency common post-RYGB), iron (especially women), calcium and vitamin D (metabolic bone disease), thiamine, folate. Annual weight, metabolic parameters, and psychological review. Pregnancy should be deferred 12–18 months post-surgery.

Access and cost: private cost AU$15,000–25,000 typically; private health insurance may cover with appropriate waiting periods. Public bariatric surgery is available in major centres but access is limited and wait times are long; eligibility and criteria vary by state.

For motivated patients with early type 2 diabetes (diagnosis under 6 years) and BMI 27–45, a supervised very low-calorie diet (VLCD) of ~800 kcal/day for up to 12 weeks can achieve T2DM remission — the DiRECT trial (Lancet 2018) demonstrated 46% remission at 12 months. This is a structured medical intervention, not a DIY approach.

D. Australian operations

Lifestyle and dietary evidence

The PREDIMED trial (NEJM 2018) demonstrated that a Mediterranean dietary pattern supplemented with olive oil or nuts reduced major cardiovascular events by ~30% in people at high cardiovascular risk — it is the dietary pattern with the strongest cardiovascular outcome evidence and is recommended by the Heart Foundation.

The National Obesity Strategy 2022–2032 sets the overarching AU government framework, with emphasis on addressing environmental and social determinants of obesity — not just individual behaviour.

MBS billing pathways

General practitioner consultations — standard items (23/36/44) for assessment and management.

GP Chronic Condition Management Plans (GPCCMP) — items 965 (preparation) and 967 (review); applicable when obesity coexists with a chronic condition (type 2 diabetes, hypertension, OSA, NAFLD, osteoarthritis); provides up to 5 allied health sessions per year (10 for ATSI patients) for dietitian, exercise physiologist, and psychologist.

Heart Health Check — item 699 or 177 for patients aged 45 and over or Aboriginal and Torres Strait Islander adults aged 30 and over.

Health assessments — 45–49 year health assessment (701), 75+ annual health assessment (705), Aboriginal and Torres Strait Islander Health Assessment (715) — all include obesity and metabolic risk assessment.

Mental Health Care Plan (MHCP) — items 2715/2717 — for comorbid depression, anxiety, or BED; 10 subsidised psychology sessions per year.

Eating Disorder Plans (items 90250–90263) — for confirmed BED with severe impairment; provides additional subsidised psychology sessions.

Bariatric surgery MBS — sleeve gastrectomy (31575), Roux-en-Y gastric bypass (31581); typically requires private health insurance for affordable access.

PBS medications

As of May 2026, no weight-management pharmacotherapy other than orlistat (OTC) is PBS-subsidised specifically for obesity. For type 2 diabetes concurrent with obesity, PBS-listed SGLT2 inhibitors and GLP-1 RA (semaglutide 1 mg, dulaglutide) provide the dual benefit of glycaemic control and weight reduction. For current PBS status of tirzepatide, see pbs.gov.au.

E. Special populations

Aboriginal and Torres Strait Islander Australians — ~71% overweight or obese with earlier-onset and higher-severity type 2 diabetes and cardiovascular disease. The ATSI Health Assessment (715) is an important engagement tool. Cultural safety and community-based approaches are central to effective obesity management in this population. Lower BMI thresholds apply for metabolic risk.

Children and adolescents — approximately 25% of AU children are overweight or obese. Management is primarily lifestyle-focused with multidisciplinary support; pharmacotherapy in adolescents (semaglutide approved by TGA in Australia for ≥12 years) should involve paediatric specialist input. Psychological and family-based interventions are first-line.

Pregnancy — obesity in pregnancy substantially raises risk of gestational diabetes, hypertensive disorders, VTE, emergency caesarean, and neonatal complications. Pre-conception weight loss where achievable is the safest strategy. GLP-1 receptor agonists are contraindicated in pregnancy; cease at least two months prior to planned conception.

Older adults — sarcopenic obesity (excess fat with low muscle mass) is common and associated with falls and functional decline. Weight management strategies must preserve lean mass — resistance training is essential. BMI-based pharmacotherapy thresholds apply cautiously; functional outcomes and quality of life may be more relevant targets than BMI alone.

Eating disorders comorbidity — BED coexists with obesity in up to 25% of those seeking weight management. Aggressive dietary restriction without psychological support can worsen BED. Screen formally (Eating Disorder Examination Questionnaire) and refer for specialist eating disorder input before initiating VLCD or intensive programmes.

Medications-driven weight gain — reassess and consider switching antipsychotics (especially olanzapine or clozapine), corticosteroids, antiepileptics, and hormonal agents where clinically appropriate. Insulin regimens in type 2 diabetes can be optimised to minimise weight gain — SGLT2 inhibitors and GLP-1 RA both assist here.

When to escalate

Refer or escalate when:

BMI ≥40 (or ≥35 with comorbidity) — refer to multidisciplinary bariatric surgery programme
Suspected secondary cause (Cushing’s, PCOS, hypothalamic obesity) — endocrinology
Suspected eating disorder or complex psychiatric comorbidity — psychiatry or specialist eating disorder service
Severe obstructive sleep apnoea — respiratory / sleep medicine
Refractory hypertension or complex dyslipidaemia alongside obesity — cardiology or internal medicine
Obesity hypoventilation syndrome (daytime hypercapnia, cor pulmonale) — emergency respiratory referral
NAFLD with FIB-4 >2.67 — gastroenterology or liver clinic
Paediatric obesity with comorbidities — paediatric specialist
Suspected idiopathic intracranial hypertension (obese woman with headache, visual change, papilloedema) — emergency ophthalmology and neurology

What this article is and is not

This is general health information drawn from current Australian general practice guidelines — NHMRC, National Obesity Strategy, RACGP, eTG Endocrinology, Heart Foundation — and landmark trials. It is not personal medical advice and does not create a doctor–patient relationship. Decisions about pharmacotherapy, surgery, or specific dietary programmes are made with your own GP and treating team.

For Australian consumer-friendly resources: HealthDirect — Obesity, Better Health Channel, LiveLighter, Obesity Collective Australia.

Sources cited

Frequently asked questions

Is obesity a medical condition or a lifestyle choice?

Obesity is recognised as a chronic relapsing disease by the World Health Organization and Australian medical bodies. Set-point biology is the key driver — after weight loss, the body compensates by increasing the hunger hormone ghrelin and reducing leptin (the fullness signal), pushing weight back toward the original set-point. This is why most people who lose weight through diet alone regain it over two to five years. Effective treatment requires medical intervention alongside lifestyle change, just as it does for hypertension or type 2 diabetes. Reducing weight stigma in clinical care is an explicit priority in the National Obesity Strategy 2022–2032.
What is metabolic syndrome and why does it matter?

Metabolic syndrome is a cluster of features that together significantly raise cardiovascular and type 2 diabetes risk. The NCEP-ATPIII criteria require central obesity (waist ≥94 cm men / ≥80 cm women for Caucasian; ≥90 cm / ≥80 cm for South Asian and East Asian) plus at least two of: triglycerides ≥1.7 mmol/L, HDL <1.0 (men) or <1.3 (women) mmol/L, blood pressure ≥130/85 mmHg, and fasting glucose ≥5.6 mmol/L. Each component multiplies cardiovascular risk; having all five roughly doubles the lifetime risk of heart disease and quintuples the risk of developing type 2 diabetes. Treating metabolic syndrome means treating all five components, not just weight.
Are medications like Ozempic or Mounjaro available on the PBS for weight loss?

No, as of mid-2026 no GLP-1 receptor agonist is PBS-subsidised specifically for weight management or obesity in Australia. Semaglutide 2.4 mg (Wegovy) and tirzepatide (Mounjaro) are TGA-approved for obesity but both carry private costs — typically AU$300–450 per month. Semaglutide 1 mg (Ozempic) and oral semaglutide (Rybelsus) remain PBS Authority-required for type 2 diabetes only. Tirzepatide had a PBAC recommendation for T2DM in early 2026 but Lilly declined the listing terms in April 2026, so it is currently private prescription only for any indication. Weight regain is common on cessation — these are chronic-disease medications, not short-course treatments.
When is bariatric surgery considered?

Australian guidelines support bariatric surgery when BMI is ≥40 kg/m², or ≥35 with significant comorbidity such as type 2 diabetes, obstructive sleep apnoea, or severe joint disease. Some specialist centres consider surgery from BMI ≥30 when type 2 diabetes is present and poorly controlled. The two most common procedures in Australia are sleeve gastrectomy (~25–30% total weight loss) and Roux-en-Y gastric bypass (~30–35% total weight loss, with high rates of type 2 diabetes remission). Both require multidisciplinary assessment pre-operatively and lifetime nutritional monitoring post-operatively. Private costs are typically AU$15,000–25,000; public access is limited and varies by state.
What diet is best for weight loss in obesity?

No single dietary pattern has been shown to be superior for long-term weight management in high-quality Australian trials; adherence and sustainability matter more than the specific pattern. The Mediterranean diet has the strongest cardiovascular outcome evidence, including in people with obesity. Low-carbohydrate and ketogenic diets produce comparable short-term weight loss to low-fat diets but show variable long-term adherence. Intermittent fasting (including 16:8 time-restricted eating) is another reasonable option with emerging evidence. A very low-calorie diet (VLCD, ~800 kcal/day for ≤12 weeks) under medical supervision can achieve type 2 diabetes remission in early disease — the DiRECT trial showed 46% remission at 12 months. Discuss options with a dietitian who can tailor the approach to preferences, culture, and comorbidities.
What are the risks of GLP-1 medications I should know about?

The most common side effect of GLP-1 receptor agonists and tirzepatide is nausea, which is managed by slow dose titration over four to eight weeks. More serious but rare effects include gallstone formation and acute pancreatitis. Gastroparesis (slowing of gastric emptying) is relevant to anaesthesia — current guidance recommends ceasing GLP-1 RA at least one week before elective surgery to reduce aspiration risk. Tirzepatide has a specific TGA December 2024 safety update: it may reduce the effectiveness of oral contraceptive pills, so non-oral or barrier contraception is recommended at initiation and for four weeks after each dose increase. These medications are contraindicated in personal or family history of medullary thyroid cancer or MEN-2 syndrome.

Source quality

Sources grouped by evidence tier. AU primary tier first; international where AU is silent or lagging; named-author reconstruction where guidelines have not yet caught up. How tiers work.