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Weight management: what works in practice?

Carrie Ruxton
Dietitian and Registered Public Health Nutritionist
Nutrition Communications Fife

Obesity occurs when body fat stores become so large that they impair health. The term "morbid obesity" is used to describe a condition that represents an immediate threat to health.
Commonly, body mass index (BMI) is used to determine whether people are obese. BMI is calculated by dividing weight in kilograms by the square of height in metres. For example, Mrs B weighs 66kg and is 1.65m tall; she would have a BMI of:
            66        =24
    (1.65 x 1.65)
As Table 1 shows, Mrs B is of normal weight.
Waist circumference is also useful for assessing risk. Health risks increase when waist circumference exceeds 94cm in men, or 80cm in women.(1) The cutoff point is lower for people of South Asian origin as their risk of type 2 diabetes and coronary heart disease are greater.


The causes of obesity are complex and are increasingly recognised as being social, behavioural and environmental, rather than solely medical or nutritional. High-fat foods, regular alcohol consumption, large portions and low levels of physical activity increase the risk of obesity. The key is to maintain a lifelong balance between "energy in" - the calories from food and drink - and "energy out" - physical activity and sport. Sadly, most people in the UK do not achieve this balance, resulting in two-thirds of adults being overweight and more than 20% being obese.(2)

Impact on health
While it is possible to be overweight and healthy, it is accepted that obesity significantly influences physical and mental health, social wellbeing, and can lead to poor confidence, low self-esteem and depression.(3) Obesity increases the risk of hypertension, heart disease, stroke, osteoarthritis, infertility, gall bladder disease, sleep apnoea and certain cancers, such as breast cancer.(4) Women with a BMI over 30 are 27 times more likely to develop type 2 diabetes than women with a normal BMI. For obese men, the risk is seven times higher.(5)
When treating patients, health professionals should always avoid a negative, blaming attitude. Successful weight loss, regular support and even short-term anti-depressant treatment can help address the psychological problems associated with obesity.
The NAO has estimated that obesity costs the UK £500m per year.(4) Most is spent on medical care, treatments and drugs for comorbidities. In addition, obesity accounts for 18 million days of sick leave, suggesting that the wider community costs could be much higher.

Is it treatable?
If the weight loss goals are realistic and sustainable the answer is "yes". A weight loss of 0.5-1.0kg (1-2lb) per week, supported by regular long-term follow-up, is more likely to work than rapid weight loss in the short-term. A reliance on the latter approach usually results in weight regain within 2-5 years.
The concept of a healthy weight has been encouraged by organisations such as Scottish Intercollegiate Guideline Network (SIGN).(1) Patients are advised to reach and maintain a weight that is 5-10% below baseline. Even a modest weight loss can significantly reduce the risk of type 2 diabetes and hypertension.

What works?
Weight management interventions can be divided into those that can be implemented in primary care settings; those that require referral or a prescription; and those that require specialist input. Regardless of the setting, it is important for treatments to be evidence-based.

Level 1 treatments

In-house sessions
These may be one-to-one or group sessions led by nurses or health visitors. Nurses can recommend reductions in dietary fat and alcohol (1,500 calories for women and 1,800 for men per day), increased physical activity (30 minutes a day) and behavioural support.(6) They can refer to "Exercise on Prescription" initiatives(7) and suggest strategies to avoid problem-eating such as late night bingeing.
While short-term studies on high-fat, low-carbohydrate and low-glycaemic-index (GI) diets look good, it is still not known whether they are safe in the long term. Low-GI diets attempt to reduce carbohydrates such as white rice, processed cereals and soft drinks that have a large impact on serum insulin. There is evidence that low-GI diets are beneficial and safe.

Slimming on Referral
The downside of in-house weight management services is that they require set-up, training and resourcing. Nonattendance rates are often high, and it is not ­usually possible to offer the more popular evening sessions. Some primary care organisations are now using "Slimming on Referral" as a way of offering choice to patients. This includes providing vouchers for free or reduced-cost attendance at local commercial slimming groups.(8) A study found that the service integrated well into the work of practices and patients lost weight.(8) The NAO has cited "Slimming on Referral" as a means of expanding weight management services in the NHS.(4)

Over-the-counter remedies
Alternative herbal remedies are increasingly popular. These may include guarana, bitter orange, conjugated linoleic acid, chitosan, caffeine and extract of green tea. Research on many of these ingredients suggests evidence for a modest weight loss;(9) however, little work has been carried out on the formulations for sale in chemists and health food shops. One exception is the Zotrim formulation (Natures Remedies). Both a randomised controlled trial(10) and a consumer study(11) found significant weight losses, respectively 5kg after six weeks and 2kg after one month. The mechanism is likely to be prolonged satiety after meals due to slower gastric ­emptying, as highlighted by a trial using ultrasound.(10)

Level 2 treatments
Referral to a dietitian can help those who need additional calorie restriction - for example, a very low-calorie diet to act as a kickstart. Another option is treatment with antiobesity drugs, such as sibutramine (Reductil; Abbott) or orlistat (Xenical; Roche). There is good evidence that they assist in weight loss,(12) although National Institute for Clinical Excellence (NICE) guidelines state that they should be used only in conjunction with dietary change, increased physical activity and behavioural strategies, and only after ­people have tried nondrug therapies.
Nurses can have major input into therapies that combine drug treatment and other therapies. The Counterweight project introduced an evidence-based weight management service into 62 GP practices.(13) The project had four stages of implementation: practice audit, support and training, nurse-led patient intervention, and evaluation. Both individual and group therapies were used. Dietary advice was based on goal setting or modest calorie restriction. Techniques to increase physical activity were included, as was behavioural therapy. Results showed that more than a third of patients achieved a weight loss of at least 5% ­baseline by 12 months.

Level 3 treatments
Only a few areas have access to morbid obesity specialists and the intensive programmes they offer. This is a pity as many therapies, such as physical activity or slimming groups, are not suitable for morbid patients, who may have multiple comorbidities and associated psychological problems.
Surgery is effective in treating morbid obesity(12) but is rarely performed in the UK. The NICE guidelines recommend it only for adults for whom all nonsurgical treatment strategies have failed. It is generally only offered to patients with a BMI over 40 unless major comorbidities are evident. The safest type of operation is vertical banded gastroplasty, which reduces the capacity of the stomach.

Policy issues
A survey of 340 primary care organisations showed that less than 50% had an obesity service and, where one existed, patients from only 25% of GP clinics had access.(14) Reasons may include low prioritisation of specialist obesity services or uncertainty about effectiveness.
The lack of obesity services has also been highlighted by a committee of MPs.15 The public health white paper, Choosing Health,16 recommended that obesity services be upgraded to include regular monitoring and personalised advice on diet, physical activity and behavioural strategies. If passed into legislation, there may be targets for obesity treatment that would impact on the work of nurses in primary care. Another important policy is practice-based commissioning,17 as this will enable practices to purchase external assistance to address obesity - for example, dietitians or vouchers for "Slimming on Referral".

Given the number of patients who are overweight or obese, nurses have an important role in assessment and provision of weight management services. The new national public health agenda could require primary care to provide more choice to patients within evidence-based treatments. This could reasonably include modest calorie restriction, physical activity, advice on herbal remedies, "Slimming on Referral" and combination therapies including drug treatment.


  1. Scottish Intercollegiate Guidelines Network. Obesity in Scotland. Integrating prevention with weight management. No 8. Edinburgh: SIGN; 1996.
  2. Rennie KL, Jebb SA. Obes Rev 2004;6:11-2.
  3. Johnston E, et al. Can J Pub Health 2004;95:179-83.
  4. National Audit Office. Tackling obesity in England. Report by the Comptroller and Auditor General. London: NAO; 2001.
  5. Scottish Executive. Scottish Diabetes Framework. Edinburgh: Scottish Executive; 2002.
  6. Avenell A, et al. J Hum Nutr Dietet 2004;17:317-35.
  7. Department of Health. Exercise on prescription. 2001. Available from URL: PublicationsAndStatistics/PressReleases/PressReleasesNotices/fs/en?CONTENT_ID=4010718&chk=LWsNgu
  8. Slimming World. Slimming on ­referral: tackling obesity in primary care. A feasibility study to assess the practicalities of working in partnership with the commercial slimming sector. Alfreton: Slimming World; 2004.
  9. Ruxton CHS, Gardner E. A review of weight loss products. Br Food J In press 2005.
  10. Andersen T, Fogh J.J Hum Nutr Dietet 2001;14:243-50.
  11. Ruxton CHS, et al. Effects of an over-the-counter herbal weight management product (Zotrim™) on weight and waist circumference in a sample of overweight women:a consumer study.Nutr Food Sci In press 2005.
  12. Avenell A, et al. Health Tech Assess 2004;8.
  13. The Counterweight project team.J Hum Nutr Dietet 2004;17:191-208.
  14. Dr Foster. Obesity management in the UK. 2004. Available from URL:
  15. House of Commons Health Committee. Obesity: third report of session 2003-04. London: TSO; 2004.
  16. Department of Health. Choosing health. London: TSO; 2004.
  17. Department of Health. Practice-based commissioning. 2004. Available from URL: PolicyAndGuidance/OrganisationPolicy/Commissioning/PracticeBasedCommissioning/fs/en

Slimming on Referral Report available from Slimming World Clover Nook Road Alfreton
DE55 4RF
National Obesity Forum
National Institute for Clinical Excellence