On the scale of it

Obesity has been defined by the Royal College of Physicians as “a disorder in which excess fat has accumulated to an extent that health may be adversely affected”.1 The chief medical officer has identified overweight and obesity as priorities for action as they are major causes of preventable ill health problems in the UK.2

The figures are startling. More than half of the UK’s population is overweight and more than 22 per cent of men and 23 per cent of women are obese, that is they have a body mass index (BMI) of more than 30 kg/m2.3 BMI is a person’s weight (in kgs) divided by the height squared (in metres). BMI is used as a surrogate for body fat, values more than 25 indicate a person is overweight, more than 30 they are considered obese and above 40, they have morbid obesity.

But it is not just the number of overweight and obese people that is causing concern, it is the rate at which the population is putting on so much weight that they are becoming classed as overweight and obese. Studies report that the number of obese adult women in the UK has nearly trebled in 20 years 2002, from about 8 per cent to 23 per cent. In men, the rates have nearly quadrupled, from 6 per cent to 22 per cent.

Rates are predicted to continue to soar unless radical action is taken. To date, there has been little concerted and co-ordinated effort on obesity by the Government. This is likely to change given the increasing prevalence of the condition, the cost to the NHS and society and the recent report from a Commons Select Committee. A start has been made with the five-a-day campaign to encourage increased consumption of fruit and vegetables and initiatives such as putting fruit in schools.

For individuals, obesity maybe important for reasons of cosmetic appearance and self esteem. But for healthcare professions it is the co-morbidities and the benefits of weight loss in reducing the risks of ill health.

The Framingham Heart study reports an increase in risk of early death by 1 per cent for each extra pound increase in weight between the ages of 30 and 42 years and 2 per cent for each extra pound between 50 and 62 years.4 Raised BMIs above 30 are associated with twice the risk of heart failure when compared to someone of normal weight; the risk of hypertension and the relative risk of cardiovascular disease also increases as the BMI rises.5

The biggest effect of excess fat is the increased risk of developing diabetes as studies show that BMI is the most important predictor of diabetes. In women, a BMI of more than 25 increases the risk by fivefold, but a BMI of more than 35 increases the risk by 93fold. In men the risk of developing diabetes increases when the BMI exceeds 24 and is increased 42 times if the BMI is greater than 35.6

Diabetes is often, but not exclusively, found as part of a condition called Metabolic Syndrome where there are associated disorders of lipids and hypertension and a strong association with central (abdominal) obesity, hence the importance of waist measurement to identify this particularly at-risk group.

But the effects of obesity are not restricted to cardiovascular complications. Obesity is also associated with increased risk of gallstones, cancers (of the breast, uterus and pancreas), impaired reproductive function and exacerbation of the disability associated with osteoarthritis. The deposition of fat in the neck is associated with sleep apnoea, which leads to daytime sleepiness and increased risk of accidents, both occupational and on the roads.7,8 Obesity also affects mobility, increases the risk of venous thrombosis, it may affect aerobic fitness and impact on jobs where there are specific fitness standards.

Why are we so obese?

There has been a long debate about the role of genetics versus the environment in determining weight gain, weight loss and the epidemic of obesity. Studies of adopted children have shown that the weight of the biological mother and to a lesser extent the biological father, are greater predictors of weight in the child than their adoptive parents, suggesting a stronger genetic component in weight gain. However, the gene pool cannot have changed significantly in the past 20 years to explain the rise in obesity.

Our lifestyle has changed considerably over this period with increased calorie-dense food, snacking, eating out, promotions such as meal deals and super sizing. This has been accompanied by reductions in physical activity, less exercise getting to and from work, less sports at school, more car use, more computer, TV and internet use and less free time to exercise. In the workplace the conventional heavy industries have been gradually replaced with the service industry, with call centres and office work where energy expenditure is much lower. It has been estimated that between 30 per cent and 50 per cent of obesity is genetically determined and the balance between genetic influences and environment has been described as “nature loads the gun and the environment pulls the trigger”.

Prevention and management in the workplace

The workplace has been identified in Choosing Health, the consultation document on public health recently published by the Department of Health as one of the areas for intervention. Occupational health nurses (OHN) have a key role in identifying and engaging populations that do not normally consult their GPs and are therefore not likely to be captured by primary care initiatives.

OHNs can help prevent obesity by both strategic and individual approaches:

– Strategically engage, advise and educate workers and employers

– Engage those who design work and the workplace to incorporate opportunities for exercise and physical activity, such as providing bike sheds, car parks away from the entrance doors and eating stations away from work areas so individuals walk to them

– Advise on the nutritional content of food in the canteens and restaurants and in business lunches. Ensuring that catering departments offer healthier options and label food so healthy choices can be made

– Educate the workforce on the dangers of obesity, its prevention and the range of management options available

– Individually, by providing information, support and if resources allow, opportunities for weighing and discussion on diet and exercise

Principles of weight management

The cornerstone of management of excess weight is through diet and physical activity. The general dietary advice is to eat less saturated fat and sugars, add less salt and eat at least five portions of fruit and vegetables a day. Dieticians aim to provide enough advice so that patients have about a 600 calorie a day deficit in their diet, which leads to a weight loss of between 1lb and 2lb a week. Actual deficits can be adjusted for individual patients. Recommendations are made about a balance across the five food groups, with suggestions of how foods can be substituted. Advice includes reducing fatty foods and those high in sugar, reducing snacking and eating three regular meals a day and moderating the consumption of low-calorie fizzy drinks.

From a medical perspective, significant health benefits are gained through loss of between 5 per cent and 10 per cent of original body weight. However, people may seek weight loss for appearance or social esteem. It is important at the onset to understand each other’s perspective and to set realistic targets that can be met.

Many people will have failed to lose weight before and further failure can lead to a cycle of loss of self-esteem, depression and weight gain. Even what they perceive as small weight losses can have powerful health benefits for them and can be viewed as success. Slow weight loss is desirable as it is more sustainable and more likely to result in lasting weight loss than crash diets, which carry the risk of gallstones and usually lead to weight gain within a short period of time.

OHNs with training and a special interest in obesity and weight management can not only provide dietary information and advice but can also help motivate staff, encourage them to see the benefits of weight loss and the disadvantages of weight gain and support them through the process. They can also identify people who binge eat as this group may need evaluation and treatment from a clinical psychologist to help them reach their goals.

Studies show that increased physical activity is important in keeping weight off, yet few people meet the Government’s recommendation of 30 minutes of moderately intensive physical activity at least five days a week. OHNs can advise staff that they may be able to access, via GPs, exercise on prescription at sports centres. This has been successful because the free classes and sessions are tailored to the needs of the individual under the supervision of trained instructors. Other schemes may exist locally, such as Walking for Health, which consists of organised walks in towns and countryside.

For those who do not want to formally exercise, advice on walking a few more stops before getting on the bus, parking at the other side of the supermarket car park, using stairs not lifts or escalators and cycling for pleasure, can all help increase physical activity.

When more is needed

As an adjunct to dietary modification and increased physical activity, people who have a BMI of more than 30, or more than 27 with complications, maybe suitable candidates for drug therapy. The two main drugs on the market work by different mechanisms. Orlistat (Xenical – Roche) reduces fat absorbed from the gut. Sibutramine (Reductil- Abbott) works centrally and is a satiety enhancer – it is particularly useful for patients for whom portion size is a problem as they feel fuller and satisfied, sooner.

The National Institute for Clinical Excellence (NICE) recommends both medications but as an adjunct to the mainstay treatment of diet and exercise.9,10 They can be a useful boost and assist in weight loss but there are criteria that need to be met before they can be prescribed. Where medical treatment fails and the health risks are significant, NICE recommends surgery which, with newer techniques, has a low mortality and morbidity rate but access is limited to specialist centres and demand is high.11

How to get started

– Have you got the necessary skills to advise on diet, exercise and weight management? Tailor your involvement to your competence

– Identify what resources/facilities/schemes are available locally and how they can be accessed

– Engage senior managers to understand that obesity is an issue of importance in their workplace

– Review food available at work – are there healthy choices in restaurants, snack bars, vending machines, buffet lunches?

– Is there any encouragement to exercise – bike racks, loans to buy bikes, membership of gyms?

– Consider the possible impact of the obese driver and the risk of accidents due to sleep apnoea

– Provide information to staff, encourage and support their efforts to lose weight (from just providing leaflets or websites they can access, to organising your own clinics)

Key points

– Health benefits result from a loss of between 5 per cent and 10 per cent of body weight in an obese patient

– Expectations need to be managed and there is no quick fix

– Aim for slow steady weight loss 

– Encourage physical activity to keep weight off

– Exercise on prescription a valuable tool

– Drugs and surgery have their place

Dr Nerys Williams is consultant occupational physician and honorary consultant in obesity and weight management at Birmingham Heartlands and Solihull NHS Trust


1. Storing up Problems: the medical case for a slimmer nation. Report of Working party 2003. Royal College of Physicians, London

2. Department of Health. Annual report of the chief medical officer. 2002. London. DoH 2002.

3. Joint Health Surveys Unit (on behalf of the Department of Health). Health Survey for England 2002. Norwich. Stationery Office 2003

4. Hubert HB, Feinleib M, McNamara PM, Castelli WP. Obesity as an independent risk factor for cardiovascular disease: a 26-year follow-up of participants in the Framingham Heart Study. Circulation 1983;67:968-77

5. Finer N. Obesity. CME Endocrinology. Clinical Medicine 2003;3(1);23-27

6. Colditz GA, Willett WC, Rotnitsky A, Manson JE. Weight gain as a risk factor for clinical diabetes in women. Arch Int Med 1995;122:481-86

7. Lindberg E, Carter N, Gislason T, Janson C. Role of snoring and daytime sleepiness in occupational accidents. The American Journal of Respiratory and Critical Care Medicine 2001: 164;2031-5.

8. Teran-Santos J, Jimenez-Gomez A, Janson C. The association between sleep apnoea and the risk of road traffic accidents. Cooperative Group Burgos-Santander. The new England Journal of Medicine 1999; 340: 847-51

9. National Institute for Clinical Excellence. Guidance on the use of orlistat for the treatment of obesity in adults. Technology Appraisal Guidance No. 22. London, NICE 2001.

10. National Institute for Clinical Excellence. Guidance on the use of sibutramine for the treatment of obesity in adults. Technology Appraisal Guidance No. 31. London, NICE 2001.

11.  National Institute for Clinical Excellence. Guidance on the use of surgery to aid weight reduction for people with morbid obesity. Technology Appraisal Guidance No. 46 London, NICE 2002



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