Obesity is a chronic medical condition requiring comprehensive, evidence-based treatment tailored to individual circumstances. In the UK, clinical intervention is recommended when BMI reaches 30 kg/m² or above (or 27.5 kg/m² for certain ethnic groups), particularly when obesity-related health complications are present. Treatment options range from structured lifestyle programmes and prescription medications to specialist weight management services and bariatric surgery. The NHS provides integrated care pathways aligned with NICE guidance, emphasising early intervention and multidisciplinary support. This article explores medical, pharmacological, and surgical obesity treatments available through UK healthcare services, helping you understand when to seek professional help and what interventions may be appropriate for your situation.

Understanding Obesity and When to Seek Treatment

Obesity is a chronic medical condition characterised by excessive body fat accumulation that presents health risks. In the UK, obesity is clinically defined using body mass index (BMI), with a BMI of 30 kg/m² or above indicating obesity, and 40 kg/m² or above indicating severe obesity. For individuals of South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean family origin, lower BMI thresholds apply: a BMI of 27.5 kg/m² or above carries equivalent health risks to a BMI of 30 kg/m² in the general population, and clinical intervention may be considered at these lower levels. Waist circumference also helps assess central adiposity risk: measurements of 94 cm or more in men (90 cm or more for South Asian men) and 80 cm or more in women indicate increased risk.

Obesity significantly increases the risk of developing serious health conditions including type 2 diabetes, cardiovascular disease, certain cancers, osteoarthritis, and sleep apnoea. It can also affect mental health, contributing to depression, anxiety, and reduced quality of life. The condition results from a complex interplay of genetic, environmental, psychological, and physiological factors, rather than simply a lack of willpower.

When to seek treatment:

• Your BMI is 30 kg/m² or above (or 27.5 kg/m² or above for certain ethnic groups)

• You have obesity-related health complications such as hypertension, prediabetes, or joint problems

• Previous weight loss attempts through diet and exercise alone have been unsuccessful

• Your weight is significantly impacting your daily activities or mental wellbeing

The NHS recommends consulting your GP if you are concerned about your weight. Your doctor will conduct a comprehensive assessment including BMI calculation, waist circumference measurement, evaluation of comorbidities, and discussion of previous weight management attempts. Early intervention is crucial, as modest weight loss of 5–10% of body weight can produce significant health benefits, including improved blood glucose control, reduced blood pressure, and decreased cardiovascular risk. NICE guidance (CG189) emphasises that obesity treatment should be individualised, combining multiple approaches tailored to each person's circumstances. Referral pathways typically include Tier 2 community lifestyle programmes, Tier 3 specialist weight management services, and Tier 4 bariatric surgery, with local integrated care board (ICB) criteria determining access.

Medical Treatment Options for Obesity

Medical treatment for obesity encompasses a range of evidence-based interventions delivered through primary and secondary care services. The NHS provides structured weight management programmes that combine dietary advice, physical activity guidance, and behavioural support. According to NICE guidelines (CG189, PH53), treatment intensity should be proportionate to the degree of obesity and presence of comorbidities.

Multicomponent weight management programmes form the foundation of medical obesity treatment. These typically run for 12 weeks or longer and include:

• Dietary interventions with registered dietitians

• Structured physical activity plans tailored to individual capability

• Behavioural change strategies addressing eating patterns and triggers

• Psychological support for emotional eating and motivation

• Regular monitoring and accountability measures

These programmes have demonstrated effectiveness in achieving clinically meaningful weight loss when participants engage consistently. The NHS Diabetes Prevention Programme and specialist weight management services offer such interventions, with referral criteria varying by local commissioning arrangements.

Tier 3 specialist weight management services provide more intensive support for individuals with complex obesity, typically those with BMI ≥40 kg/m² or ≥35 kg/m² with significant comorbidities (lower thresholds apply for some ethnic groups). These multidisciplinary services include physicians, specialist nurses, registered dietitians, psychologists, and physiotherapists who address medical, nutritional, psychological, and physical aspects simultaneously.

Very low-calorie diets (VLCDs) of 800 kcal per day or less may be recommended under medical supervision for rapid initial weight loss, particularly for individuals with type 2 diabetes. These meal replacement programmes require careful monitoring for nutritional adequacy and potential side effects including fatigue, constipation, and gallstone formation. NICE supports VLCD use as part of comprehensive programmes with appropriate clinical oversight, typically for 8–12 weeks followed by gradual food reintroduction and long-term weight maintenance strategies. VLCDs should be time-limited and include structured refeeding protocols.

Prescription Medications for Weight Management

Prescription medications for obesity work through various mechanisms to support weight loss alongside lifestyle modifications. NICE recommends pharmacological treatment only after dietary, exercise, and behavioural approaches have been attempted.

Orlistat is currently the primary weight-loss medication available through the NHS for adults with BMI ≥30 kg/m² or ≥28 kg/m² with obesity-related comorbidities (such as type 2 diabetes or hypertension). This lipase inhibitor works by blocking approximately 30% of dietary fat absorption in the gastrointestinal tract. The unabsorbed fat is excreted, reducing overall calorie intake. Orlistat is taken as a 120 mg capsule three times daily with meals containing fat. Common adverse effects include:

• Oily spotting and faecal urgency

• Flatulence with discharge

• Increased bowel movements

• Abdominal cramping

These gastrointestinal effects can be minimised by adhering to a low-fat diet (approximately 30% of calories from fat). Orlistat may also reduce absorption of fat-soluble vitamins, so multivitamin supplementation taken at bedtime is recommended. Treatment should be discontinued if less than 5% weight loss is achieved after 12 weeks. Important interactions include ciclosporin (separate by at least 3 hours), warfarin and other anticoagulants (monitor INR closely), levothyroxine (separate by at least 4 hours), and amiodarone. Orlistat is contraindicated in chronic malabsorption syndromes and cholestasis. It should not be used during pregnancy or breastfeeding.

GLP-1 receptor agonists such as liraglutide 3.0 mg (Saxenda) and semaglutide 2.4 mg (Wegovy) represent newer pharmacological options. These medications, originally developed for type 2 diabetes, work by mimicking the incretin hormone GLP-1, which increases insulin secretion, slows gastric emptying, and reduces appetite. In the STEP clinical trials, semaglutide produced a mean weight loss of approximately 15% of body weight over 68 weeks. However, NHS availability is restricted. NICE Technology Appraisal TA875 recommends semaglutide only for adults with at least one weight-related comorbidity and initial BMI ≥35 kg/m² (or ≥32.5 kg/m² for certain ethnic groups), within specialist weight management services, and only if specific stopping rules are met (discontinue if less than 5% weight loss at 6 months). NICE TA664 sets similar criteria for liraglutide 3.0 mg. These medicines are administered by subcutaneous injection.

Common adverse effects of GLP-1 receptor agonists include nausea, vomiting, diarrhoea, and constipation, which often improve over time. Risks include cholelithiasis and gallbladder disease, and rare cases of pancreatitis. In people with type 2 diabetes, there is a risk of worsening diabetic retinopathy. GLP-1 receptor agonists are contraindicated in pregnancy and breastfeeding and should be stopped at least 2 months before a planned pregnancy. Your GP or specialist will assess suitability based on your medical history, current medications, and contraindications. Regular monitoring of weight loss progress, side effects, and comorbidity improvement is essential.

If you experience a suspected side effect to any medicine, report it via the MHRA Yellow Card scheme at yellowcard.mhra.gov.uk or through the Yellow Card app.

Surgical Interventions for Severe Obesity

Bariatric surgery represents the most effective treatment for severe obesity, producing substantial and sustained weight loss alongside improvement or resolution of obesity-related comorbidities. NICE (CG189) recommends considering bariatric surgery for adults with BMI ≥40 kg/m² or ≥35 kg/m² with significant obesity-related conditions such as type 2 diabetes or severe sleep apnoea, provided non-surgical measures have been attempted. For individuals of South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean family origin, these thresholds are reduced by 2.5 kg/m². Surgery may also be considered for people with recent-onset type 2 diabetes and BMI 30–34.9 kg/m² (or 27.5–32.4 kg/m² for the ethnic groups listed) as a metabolic intervention.

Types of bariatric procedures available through the NHS include:

Gastric bypass (Roux-en-Y) creates a small stomach pouch connected directly to the small intestine, bypassing most of the stomach and duodenum. This restrictive and malabsorptive procedure typically produces 60–70% excess weight loss. It works through reduced stomach capacity, altered gut hormone secretion, and decreased nutrient absorption.

Sleeve gastrectomy involves removing approximately 80% of the stomach, creating a narrow tube or 'sleeve'. This restrictive procedure reduces stomach capacity and removes ghrelin-producing cells, decreasing appetite. Weight loss typically reaches 50–60% of excess weight.

Gastric band placement involves positioning an adjustable silicone band around the upper stomach, creating a small pouch. This purely restrictive procedure is now less commonly performed due to higher complication and revision rates compared to other procedures.

All bariatric procedures require comprehensive preoperative assessment including psychological evaluation, nutritional counselling, and medical optimisation. Patients must demonstrate commitment to lifelong dietary changes and supplementation. Potential complications include:

• Nutritional deficiencies (iron, vitamin B12, calcium, vitamin D, thiamine)

• Dumping syndrome (rapid gastric emptying causing nausea and diarrhoea)

• Gallstone formation

• Surgical complications such as leaks, strictures, or internal hernia (post-bypass)

• Thiamine deficiency, especially with prolonged vomiting

Seek urgent medical review if you experience severe abdominal pain, persistent vomiting, or signs of anastomotic leak after surgery. Lifelong follow-up with specialist services is essential for monitoring nutritional status according to British Obesity and Metabolic Surgery Society (BOMSS) guidance, managing complications, and supporting weight maintenance. Bariatric surgery produces significant improvements in type 2 diabetes, hypertension, sleep apnoea, and cardiovascular risk, with evidence suggesting reduced long-term mortality compared to non-surgical management of severe obesity.

Lifestyle Modifications and Support Programmes

Sustainable lifestyle modification forms the cornerstone of successful long-term weight management, regardless of whether medical or surgical interventions are employed. Evidence consistently demonstrates that combining dietary changes, increased physical activity, and behavioural strategies produces superior outcomes compared to any single approach.

Dietary modifications should focus on creating a sustainable calorie deficit whilst ensuring nutritional adequacy. NICE recommends:

• Reducing total calorie intake by 600 kcal per day for gradual, sustainable weight loss

• Emphasising whole foods including vegetables, fruits, whole grains, and lean proteins

• Limiting processed foods high in sugar, saturated fat, and salt

• Controlling portion sizes and eating mindfully

• Avoiding restrictive diets that cannot be maintained long-term

Referral to NHS dietetic services provides personalised nutritional guidance addressing individual preferences, cultural considerations, and medical conditions. Registered dietitians can help identify problematic eating patterns and develop practical strategies for sustainable change.

Physical activity recommendations follow the UK Chief Medical Officers' Physical Activity Guidelines (2019): gradually build to 150–300 minutes of moderate-intensity activity weekly, or 75–150 minutes of vigorous activity. This might include brisk walking, cycling, swimming, or structured exercise classes. For individuals with limited mobility or significant obesity, starting with short bouts of activity and progressively increasing duration and intensity is appropriate. Resistance training twice weekly helps preserve muscle mass during weight loss. Reducing sedentary time and breaking up prolonged sitting are also important.

Behavioural support programmes address psychological aspects of eating and weight management:

• Identifying emotional eating triggers

• Developing alternative coping strategies for stress

• Setting realistic, achievable goals

• Self-monitoring through food diaries or apps

• Problem-solving barriers to healthy behaviours

• Building social support networks

The NHS provides various support options including group-based programmes, one-to-one counselling, and digital resources. Commercial programmes such as WW (Weight Watchers) may be recommended, with some areas providing vouchers for attendance.

Other modifiable factors that your GP may discuss include sleep hygiene, alcohol intake, and a medicines review, as some medications (such as certain antipsychotics, insulin, sulfonylureas, and some antidepressants) are associated with weight gain.

When to contact your GP:

• You are struggling to lose weight despite consistent efforts

• You experience concerning symptoms during weight loss

• You need referral to specialist services

• Mental health concerns are affecting your weight management

Long-term success requires ongoing support, regular monitoring, and adjustment of strategies as circumstances change. Weight maintenance after loss is challenging, with continued engagement in support programmes significantly improving outcomes.

Frequently Asked Questions