Susan Jebb, PhD, SRD; Nilani Sritharan, BSc (Hons), ANutr.
Susan-Head of Nutrition and Health; Nilani- Nutritionist, Medical Research Council Human Nutrition Research, Cambridge.
Rates of obesity have trebled in the past two decades. Currently in the UK almost a quarter of adults are clinically obese (with a body mass index (BMI) of >30). A further 33% women and 43% men are overweight (with a BMI of 25-30) (Sprostan and Primatesta, 2003).
The situation in children is no less serious: about one in five are considered to be overweight (a 50% rise since the 1980s) and one in 20 are obese (Sprostan and Primatesta, 2002).
Conservative estimates put obesity-related costs to the Exchequer at over £2 billion a year - a figure that doubles when the health- related costs of an overweight population are included in the equation. Most people recognise that obesity can shorten life expectancy - by nine years on average, but few recognise its profound impact on almost every part of the body. It increases the risk of Type 2 diabetes, heart disease, high blood pressure, some cancers (especially breast, colon and kidney cancers), osteoarthritis and back problems, respiratory and sleep disorders, and even infertility.
Given the strong links between obesity and chronic disease, it is not surprising that the Government White Paper Choosing Health: Making healthy choices easier has a strong focus on obesity (DH, 2004).
There is a Government Public Service Agreement target to halt, by 2010, the year-on-year rise in obesity among children under 11, in the context of a broader strategy to address the issue in the population as a whole. The exact details of measures to support the attainment of this target are yet to be released. However, the Government has asked the National Institute for Clinical Excellence to consider comprehensive guidelines for the prevention and treatment of obesity, and the White Paper sets out a number of other initiatives to help people achieve a healthy weight (see Latest policy box, below).
Although the exact details of Government plans are yet to be confirmed, it is clear that weight management is set to become an increasingly important part of patient care. Most nurses recognise the importance of a healthy weight, but many also feel inadequately trained to take on this complex task.
Body mass index
Obesity is most commonly assessed using the BMI to classify an individual, based on internationally recognised cut-offs (see Table 1, page 27). However, clinical judgement is also important, especially in elderly patients where height may be distorted by kyphosis, in athletes who have a greatly increased muscle mass or in others with an unusual body composition.
The calculation is made as follows:
BMI (kg/m2)= weight (kg)/height x height (m)
Recognising obesity in children is more difficult because BMI varies with age and gender. The Child Growth Foundation produces useful growth charts to allow BMI to be plotted for an individual child. Children should be referred for specialist support if they have a BMI >98th centile. However, rather than relying on single measurements it is also important to look out for children who are on an upward trajectory, persistently crossing centiles, as an index of individuals at risk.
Waist circumference is an alternative method for assessing the risk of disease associated with excess weight in adults. Abdominal fatness is much more strongly associated with health risks than overall fatness (see Table 2).
Setting realistic goals
Few patients who present with clinical obesity will be able to reduce their weight to attain a BMI <25kg/m2. However, it is clear that even modest weight loss is associated with significant metabolic benefits. Many patients hope to achieve losses of 30% or more but they are ultimately disappointed with their achievements. This makes it difficult to sustain weight loss. Setting realistic goals is a critical component of successful weight management. For most patients, losing 5% in three months and 10% in six months is a real success. This brings clear metabolic benefits (Table 3) and most patients will achieve significant improvements in quality of life, experiencing less breathlessness and better mobility.
Building motivation and confidence
To be successful a patient needs to be both motivated and confident. Health professionals often slip into providing advice before a patient is actually ready to hear this information. Time spent building motivation and confidence will reap rewards.
Patients need to understand that losing weight means eating less, exercising more or, ideally, a little of both. While you can provide the necessary information and practical support, patients ultimately need to take responsibility for managing their weight. It is, however, worth pointing out that choosing a healthier diet and becoming more active will bring health benefits independent of weight loss.
For long-term success, lifestyle changes must be sustainable. Before advising on these, however, it is important to assess a patient’s current behaviours:
- Record their current diet and activity history (either using a food frequency questionnaire or a food and activity diary)
- Discuss who cooks and shops for food in the household, how much time is spent preparing foods, typical foods eaten and how the food is cooked (for example fried, baked and so on). The patient’s occupation may influence the time available to prepare foods, foods eaten or activity levels, for example a single parent with very young children, a shift-worker or a long-distance lorry driver will have different daily routines
- Consider the patient’s motivation and expectations that they will succeed. Have they attempted to lose weight before? If so, why were they unsuccessful? Patients need to feel confident that, with your support, they can lose weight this time around
- Dispel any myths that they may have concerning weight loss or dieting since this can be an obstacle to weight loss.
Points to consider when assessing a patient’s diet are listed in Box 1, page 29.
Dietary changes should not be seen as a ‘diet’ to which a patient adheres during a short-term period of treatment only, but rather as a change for life.
Fad diets are largely unsuccessful because they are too prescriptive, can be unbalanced and cannot be maintained in the long term. In a recent review of the efficacy of four popular commercial diets, the degree of weight lost depended on patient adherence to the diet and not on specific regimens (Dansinger et al, 2005). A gradual programme of increasing physical activity will bring health benefits without the risk of injury.
Few people can lose weight without cutting the calories they consume. A 500kcal/day deficit is associated with a weight loss of about 0.5kg a week. Reducing the proportion of fat and increasing the proportion of complex carbohydrate can lead to a spontaneous reduction in energy intake. Choosing unrefined carbohydrates with a low glycaemic index may help to curb appetite. Sugar-rich soft drinks tend to supplement the energy consumed as food. Switching to drinks containing artificial sweeteners, or preferably water, will support weight loss.
Alcohol can be a significant source of calories for some patients. Restricting intake to no more than one unit a day is a useful guide.
These changes to the quality of the diet will usually lead to modest weight loss. However, sustained weight loss will usually require a reduction in the quantity of food consumed. Portion sizes can have a huge impact on calorie intakes so it is important to review this when providing patient advice. The average portion size is almost double that of 20 years ago (Nielsen and Popkin, 2003), yet there is no evidence that eating a bigger meal leaves you feeling fuller for longer. Work conducted by Rolls and colleagues indicates that subjects fail to compensate for the greater calorie intake of a large snack portion by eating less either during that or on subsequent meal occasions that day (Rolls et al, 2004).
For patients trying to lose weight, strict portion control of energy-dense foods is essential. Learning to avoid so-called supersize options, and choosing mini- or snack-size varieties is a useful strategy.
Research shows that a structured meal pattern is associated with increased weight loss. Most eating plans are based on a three-meal-a-day pattern, but this can be extended to include planned snacks, such as fruit, a small pot of yogurt, toast or rice cakes (see Plan for Weight Loss, right).
More rapid weight loss can be achieved using meal-replacement products instead of one or two meals a day. These products are nutritionally well balanced and, for some patients, provide a convenient option and a break from the temptation of everyday foods. However, they are rarely a long-term option and patients need support to gradually return to more standard eating habits.
More is better! However, there is little point in recommending five 30-minute sessions of exercise a week for a patient who rarely gets out of their chair. Start by assessing habitual activity levels and suggest ways to gradually increase these. A pedometer can be a useful tool for self-assessment of general activities of daily life. Box 2 offers tips for increasing activity levels.
Patients who find it difficult to lose weight using these lifestyle strategies alone may derive additional benefit from taking the weight-loss agents Xenical or Reductil. These treatments provide an adjunct, not an alternative, to dietary change. Guidelines for their use are available from NICE (www.nice.org.uk).
Weight management in children
For children, the broad principles of weight control remain the same. With the exception of young people who are clinically obese beyond puberty, it is rarely necessary to consider weight loss. Instead, the focus is on preventing further weight gain, allowing children to ‘grow into their weight’. The SIGN guidelines for childhood obesity (2003) outline three key ways in which this can be achieved:
- Increasing physical activity to a minimum of 30 minutes a day
- Changing sedentary habits such as time spent in front of the TV or playing computer games
- Adopting healthy eating behaviours.
These initiatives should involve the whole family as far as possible. Interventions are more likely to be successful if the child has the support of everyone around them and sees other family members embracing these changes.
The Royal College of Paediatrics and Child Health and the National Obesity Forum have developed guidelines for managing obesity in children (RCPCH, 2004).
Maintaining weight loss
Many people have succeeded in losing weight over short periods of time. However, many regain weight later. In general, too little effort is put into weight-maintenance programmes. To be successful in the long term patients need to sustain the changes they have made, to be able to identify high-risk situations when they may be likely to overeat and to develop practical coping strategies. This may include how to shop or new cooking methods. Discussing the best choices when eating out or cooking on a budget are vital life skills for long-term weight-loss maintenance. Most patients will require extra support at times of other stressful life events in order to prevent weight regain.
While there is no magic solution to the problem of obesity and no single model will fit all, successful slimmers frequently identify specific pointers that have been key to their weight loss:
- Increasing regular activity. Those that have joined a club/classes are more likely to keep active in the longer term. Many also enjoy the social aspects of keeping active too
- Thinking about/controlling portion sizes. Thinking about portion size can help patients focus on how much as well as what they are eating. The British Heart Foundation booklet So You Want to Lose Weight … for Good provides useful information on portion sizes and can help patients understand how much is too much
- Regular mealtimes. Sticking to regular eating times (which can include healthy snacks) can help reduce the tendency to overeat later.
Box 3 lists some other characteristics of successful slimmers.
Obesity may be common but it is not inevitable. With sound advice regarding diet and activity, together with ongoing support, patients can lose weight and keep it off successfully. This will lead to significant metabolic benefits and will reduce the burden of ill health, especially insulin resistance. Successful prevention and treatment of obesity is a key step to achieving targets for reductions in the incidence of cardiovascular disease and some cancers.
Government initiatives to reduce obesity are based on raising awareness through a new strategy to actively promote health and encompass:
- A new cross-government campaign on obesity
- Improving access to healthier foods, including improving food labelling
- Improving access to physical activity, for example through sports and active travel
- Restricting the promotion of unhealthy foods to children
- Improving nutrition in schools
- Providing procurement guidance on food for public bodies
- Developing a comprehensive care pathway for obesity, to provide a model for prevention and treatment for the NHS
- Training and support for NHS staff and the introduction of accredited health trainers.
Source: Choosing Health: Making healthy choices easier (DH, 2004)
Plan for weight loss
1. 500 kcal/day deficit in intakes
2. Three main meals each day, with planned snacks
3. Decrease portions of energy-dense foods
4. Reduce fat (>30% energy) and saturated fat (<10% energy)
5. Increase carbohydrates (>50% energy) and limit simple sugars (<10% energy)
6. Increase physical activity
7. Change behaviour to optimise compliance
Gill, P. (1997) Key issues in the prevention of obesity. British Medical Bulletin 53: 2, 359-388.
Koplan, J.P., Liverman, C.T., Kraak. V.A. (eds).Committee on Prevention of Obesity in Children and Youth. (2004) Preventing Childhood Obesity: Health in the balance. The National Academies Press. Available at: www.nap.edu/
Summerbell, C. (1998) Dietary treatment of obesity In: Kopelman, P.G., Stock, M.J. Clinical Obesity. London: Blackwell Science.
Association for the Study of Obesity(www.aso.org.uk): useful fact sheets on obesity for health professionals, news updates and more.
British Heart Foundation(www.bhf.org.uk): low-cost patient-focused publications on healthy eating, food labelling and losing weight.
International Obesity Task Force(www.iotf.org): an international perspective on obesity prevalence and a useful section on the latest obesity research.
North American Association for the Study of Obesity(www.obesityonline.org): lots of visual aids including a slide library of essential obesity concepts.
National Obesity Forum(www.nationalobesityforum.org.uk): guidelines for the clinical management of obesity in adults and children, low-cost educational materials and useful links.
Weight-wise(www.bdaweightwise.com/bda): website compiled by the British Dietetic Association for individuals wishing to lose weight.
Author’s contact details
Dr Susan Jebb, Head of Nutrition and Health, MRC Human Nutrition Research, Elsie Widdowson Laboratory, Fulbourn Road, Cambridge CB1 9NL.
Dansinger, M.L., Gleason, J.A., Griffith, J.L. et al. (2005) Comparison of the Atkins, Ornish, Weight Watchers, and Zone diets for weight loss and heart disease risk reduction: a randomised trial. Journal of the American Medical Association 293: 1, 43-53.
Department of Health. (2004)Choosing Health: Making healthy choices easier. London: The Stationery Office.
Nielsen, S.J., Popkin, B.M. (2003)Patterns and trends in food portion sizes, 1977-1998 Journal of the American Medical Association 289: 450-453.
Rolls, B.J., Roe, L.S., Kral, T.V. et al. (2004)Increasing the portion size of a packaged snack increases energy intake in men and women. Appetite 42: 1, 63-69.
Royal College of Paediatrics and Child Health and the National Obesity Forum. (2004)An Approach to Weight Management in Children and Adolescents (2-18 years) in Primary Care. London: RCPCH. Available at: www.nationalobesityforum.org.uk/Approach 2PAGES TOGETHER.pdf (accessed 4 February 2005).
Scottish Intercollegiate Guidelines Network. (2003)Management of Obesity in Children and Young People (Report 69). Edinburgh: SIGN.
Steer, T., Jebb, S. (2004)Obesity: dietary treatment. Women’s Health Medicine 1: 1, 42-48.
Sprostan, K., Primatesta, P. (2002)Health Survey for England. The Health of children and young people. London: The Stationery Office.
Sprostan, K., Primatesta, P. (2003)Health Survey for England. Volume 2: Risk factors for cardiovascular disease. London: The Stationery Office.