Information intended for UK healthcare professionals only. 

This management algorithm was developed by a multidisciplinary expert panel: Tahrani et al with the support of an educational grant from Novo Nordisk Limited. See end of algorithm for full disclaimer.


  • Two out of three adults in England have overweight, with around 28% living with obesity.10,11 Similar levels of obesity are reported in Wales, Scotland, and Northern Ireland (23%, 29%, and 27% of adults, respectively)12
  • Obesity is a risk factor for long-term conditions e.g. (CV disease, type 2 diabetes, and cancer), it impacts mental health, and reduces life expectancy9
  • Rates of obesity are highest in socially deprived areas10
  • Conditions related to overweight and obesity cost the NHS around £6.1 billion a year10
  • During the coronavirus pandemic, patients who are living with overweight or obesity (BMI >25mg/m2) have had much worse outcomes from COVID-1910
  • In response, the Government has introduced new policies to reduce obesity, which include plans to:10
    • expand NHS weight management services and the NHS Diabetes Prevention Programme 
    • train primary care staff to become healthy weight coaches
    • increase interventions for obesity in primary care, including new Quality and Outcomes Framework (QOF) indicators.

Classification of obesity

  • Obesity is a complex relapsing chronic disease characterised by excess body fat that impairs health1,3
  • Obesity is defined by NICE as BMI ≥30kg/m2; while NICE does not have specific definitions for different population groups, NICE does recommend the use of a lower threshold (BMI ≥27.5) to trigger action to prevent type 2 diabetes among people of black African, African-Caribbean, and South Asian descent4,13
  • BMI should be treated with caution in muscular people, for whom waist circumference might be more useful4
  • Waist circumference is a measure of central adiposity:4,13
    • for men ≥94cm (≥90cm for South Asian men) is high, and >102 is very high
    • for women ≥80cm is high, and >88cm is very high
  • The level of intervention a patient requires is assessed according to BMI, waist circumference, the presence of comorbidities and patient choice.4

Role of the GP

  • The GP is often the first point of contact for patients with obesity and can provide continuity of care and support4
  • GPs should diagnose obesity, identify, and manage causative factors, for example, medication or underlying comorbidity (Box 1), provide non-judgemental support, explain obesity, and the role of weight management in improving health. This can be done over more than one consultation
  • An important part of the GP’s role is to consider and manage the sequelae of obesity, such as non-alcoholic fatty liver disease, type 2 diabetes, or CV disease4
  • Mental health needs must be addressed, with patients referred when needed or appropriate to a psychologist or Improving Access to Psychological Therapies (IAPT) service for assessment and treatment.4 Binge eating disorder can be detected using the Binge Eating Disorder Screener-7 (BEDS-7) screening tool (see Resources) and patients referred to an eating disorders service. Any other eating disorders should be screened for by the GP
  • Local referral criteria and resources will determine where patients should be referred for weight management. This might be to designated weight management staff in the practice, or to Tier 2, 3, or 4 services.4 Patients can attend commercial weight management or exercise programmes, self-refer to the NHS Diabetes Prevention Programme, or access an online 12-week NHS weight management service (see Resources section for NHS Inform and NHS OneYou)10
  • Regular follow-up is important to support patients with weight management.4
Box 1. Examples of medications and comorbidities that might cause or contribute to weight gain2,14


  • Endocrine problems, e.g. PCOS
  • Sleep problems, e.g. sleep apnoea
  • Respiratory conditions, e.g. asthma and COPD
  • Chronic pain, e.g. osteoarthritis
  • Depression


  • Psychotropic drugs
  • Insulin and sulphonylureas
  • Corticosteroids
  • Beta blockers


  • Be aware of the significant stigma associated with obesity, which has negative effects on people’s mental and physical health, potentially leads to further weight gain, and can impact on engagement with healthcare3
  • Using words and language that avoid stigma and prejudice can help people with obesity engage in conversations about obesity and encourage weight loss:3
    • use the term ‘living with obesity’ rather than ‘obese’ or ‘morbidly obese’ 
    • speak in a caring manner and avoid blaming the individual for the condition, for example ‘Some people with your symptoms find that losing a bit of weight can be helpful
    • focus on the positive benefits of weight management, for example ‘Exercising regularly can help improve your energy levels and might help with sleep
    • support patients to achieve specific goals that they have mentioned, for example ‘You said you’d like to lose weight so you can play with your children without feeling breathless
    • acknowledge positive actions even if they do not result in weight loss, for example ‘It’s great that you’ve started swimming. This will benefit your health even though you haven’t lost weight.

Weight management options

Supportive behaviours

  • Supportive behaviours are the backbone of weight management for all patients with obesity. These involve support for patients to make changes in behaviour, such as increasing physical activity, improving diet, and managing sleep2,4
  • Different treatments can be tried according to patient preference and previous experiences4


  • Orlistat is currently available in primary care and recommended by NICE for the management of patients with BMI ≥30kg/m2 or BMI ≥27kg/m2 with associated risk factors
    • orlistat must be combined with a low-fat diet, which may require support from a dietitian, to avoid side-effects15
    • orlistat therapy should be discontinued after 3 months if the patient has not lost at least 5% of their initial body weight; the decision to use drug treatment for longer than 12 months should be made after discussing the potential benefits and limitations with the patient4
  • Liraglutide 3 mg is recommended by NICE for use in hospital Tier 3 weight management services for the management of patients with BMI of at least 35 kg/m2 (or at least 32.5 kg/m2 for members of minority ethnic groups known to be at equivalent risk of the consequences of obesity at a lower BMI than the white population), pre-diabetes, and a high risk of cardiovascular disease8
    • liraglutide 3 mg must be combined with a reduced-calorie diet and increased physical activity8
    • treatment duration is restricted to 2 years and should be discontinued after 12 weeks at the 3 mg dose, if the patient has not lost 5% of their initial body weight8

Bariatric surgery

  • NICE recommends bariatric surgery as an option for patients with a BMI ≥40kg/m2, or if they have comorbidities with a BMI of 35–40kg/m2, if non-surgical measures have been unsuccessful, or first line if BMI >50kg/m2; and if intensive management in a Tier 3 service is provided4
  • Bariatric surgery can improve type 2 diabetes, with 60% going into remission; therefore NICE recommendations are different for patients with diabetes (lower BMI criteria)4
  • Patients need realistic expectations about the potential weight loss they can achieve
  • Patients may not be sure if they want surgery but should still be given the opportunity to have a discussion with the surgical team or Tier 3 service to assess the pros and cons.4

Post-bariatric support

  • Regular follow-up and supportive behaviours are needed after surgery. Follow-up care within the bariatric service is recommended for 2 years in the NHS, but some patients may be lost to follow-up during this period and all patients require regular life-long annual follow-up in primary care beyond this time4,17–19
  • Patients should be monitored annually to ensure they are taking nutritional supplements as advised by the bariatric team as nutritional supplements may need adjustment4,17–19
  • While surgery provides benefits to many patients, some of those with severe and complex obesity may experience mental health challenges after surgery. Regular mental health reviews in primary care are therefore essential.7 GPs should be particularly mindful of the following:20
    • problems with body image or disappointment with life after surgery, which can lead to depression
    • depression, particularly after the first 2 or 3 years post-surgery
    • addiction problems, including the use of opiates, alcohol, or drugs
    • self-harm and an increased risk of suicide.

Useful resources


  1. Wharton S, Lau DCW, Vallis M et al. Obesity in adults: a clinical practice guideline. CMAJ. 2020; 192: E875–E891.
  2. Appendix 2 (as supplied by the authors): 2020 Clinical practice guidelines: 5As framework for obesity management in adults. Appendix to: Wharton S, Lau DCW, Vallis M et al. Obesity in adults: a clinical practice guideline. CMAJ. 2020; 192: E875–E891. 
  3. Albury C, Strain WD, Le Brocq S et al. The importance of language in engagement between health-care professionals and people living with obesity: a joint consensus statement. Lancet Diabetes Endocrinol. 2020; 8 (5): 447–455.
  4. NICE. Obesity: identification, assessment and management. Clinical Guideline 189. NICE, 2014. Available at:
  5. van der Valk E, van den Akker E, Savas M et al. A comprehensive diagnostic approach to detect underlying causes of obesity in adults. Obes Rev. 2019; 20 (6): 795–804.
  6. Obesity Canada. 4Ms for interdisciplinary team weight management care: mechanical, mental, metabolic, social milieu. 2014. Available at:
  7. NHS. Types. Weight loss surgery. (Accessed 30 October 2020).
  8. NICE. Liraglutide for managing overweight and obesity. Technology appraisal guidance TA664. NICE, 2020. Available at:
  9. RCGP. Ten top tips for the management of patients post bariatric surgery in primary care. 2014. Available at:
  10. Department of Health and Social Care. Tackling obesity: empowering adults and children to live healthier lives. 2020. (Accessed 30 October 2020).
  11. NHS Digital. Statistics on obesity, physical activity and diet, England. Part 3: Adult overweight and obesity. 2020. (Accessed 30 October 2020).
  12. Baker C. Briefing paper 3336: Obesity statistics. 2019. Available at:
  13. NICE. BMI. Preventing ill health and premature death in black, Asian and other minority ethnic groups. Public health guideline 46. NICE, 2013. Available at:
  14. Wharton S, Raiber L, Serodio KJ et al. Medications that cause weight gain and alternatives in Canada: a narrative review. Diabetes Metab Syndr Obes. 2018; 11: 427–438.
  15. Amneal Pharma Europe Ltd. Orlistat 120mg hard capsules—summary of product characteristics. June 2016.
  16. Novo Nordisk Limited. Saxenda 6 mg/mL solution for injection in pre-filled pen—summary of product characteristics. September 2020.
  17. O’Kane M, Parretti H, Hughes C et al. Guidelines for the follow-up of patients undergoing bariatric surgery. Clin Obes. 2016; 6 (32): 210–224.
  18. NICE. Obesity: clinical assessment and management. Quality standard 127. NICE, 2016. Available at:
  19. O’Kane M, Parretti H, Pinkney J et al. British Obesity and Metabolic Surgery Society Guidelines on perioperative and postoperative biochemical monitoring and micronutrient replacement for patients undergoing bariatric surgery—2020 update. Obesity Reviews. 2020; 21: e13087.
  20. Bagley D. Unforeseen consequences: bariatric surgery side effects. Endocrine News. 2018. (Accessed 30 October 2020).

About this management algorithm

Disclaimer: Guidelines identified a need for clinical guidance in a specific area and approached Novo Nordisk Limited for an educational grant to support this work. This algorithm was developed by Guidelines, and the Chair and members of the working group were chosen and convened by Guidelines. The content is independent of and not influenced by Novo Nordisk Limited, who checked the final document for technical accuracy and to ensure compliance with regulations. The views and opinions of the contributors are not necessarily those of Novo Nordisk Limited, or of Guidelines, its publisher, advisers, or advertisers. No part of this publication may be reproduced in any form without the permission of the publisher.

Group members: Dr Abd Tahrani —Institute of Metabolism and Systems Research, Senior Lecturer in Metabolic Endocrinology and Obesity Medicine, Dr Helen Parretti,  General Practitioner at Beccles Medical Centre, Suffolk, Council member for the British Obesity and Metabolic Surgery Society, Mary O’Kane —Honorary Consultant Dietitian (Adult Obesity) at Leeds Teaching Hospitals NHS Trust, Fellow of the British Dietetic Association, Dr Hasan Chowhan —General Practitioner, Clinical chair of North East Essex Clinical Commissioning Group (CCG), Dr Denise Ratcliffe — Consultant Clinical Psychologist,Ms Sarah Le Brocq — Obesity UK Director.

Date of preparation: December 2020