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Preventing obesity in primary care

Sandra Drummond
BSc(Hons) PhD RPHNutr
Senior Lecturer and Programme Leader for Nutrition
Dietetics, Nutrition and Biological Sciences Department
Queen Margaret University College Edinburgh

One of the largest diet and nutrition surveys carried out in 2001 indicated that over half of all men and women were overweight and 25% of men and 20% of women were clinically obese.(1) Worryingly, the increase in obesity is occurring across all age groups, including young school children and adolescents.(2)

What causes obesity?
The aetiology of obesity is multifactorial. This is what makes the prevention and treatment of obesity so difficult. There is growing evidence that suggests genetics play a role, indicating that some individuals may be more susceptible to weight gain than others, but weight gain and obesity are still the result of an imbalance between energy intake and energy expenditure. Keeping a balance between the two is apparently becoming more and more difficult in today's society. The availability of high-fat foods, combined with our dwindling activity levels, has promoted experts to refer to our environment as "obesogenic".
 
Health benefits of weight loss for the obese
Obesity is now acknowledged as one of the UK's most important public health problems, as it contributes to an increasing noncommunicable disease burden. Obese individuals are at higher risk of diabetes, cardiovascular disease, hypertension, cancers and premature death than nonobese individuals.(3) In addition, obese individuals experience other complications such as back and joint problems, sleep apnoea, low self-esteem and depression, which can seriously impact on the individual's quality of life. With weight loss, many of these conditions can be alleviated. Weight losses of between 5 and 10% (which is achievable in primary care) have been associated with health benefits such as improved cardiovascular risk factors, reduced insulin resistance, reduced angina and reduced joint pain.(4) One of the challenges for the health professional is to encourage the obese patient to focus on a weight reduction of this magnitude - that is, to focus on a realistic and achievable weight reduction that confers health benefits. Too many patients have unrealistic expectations and, as a result, become easily discouraged.

Dietary advice for the obese patient
As obesity levels increase, there appears to be a parallel increase in the number and popularity of fad diets. It is no wonder that those wishing to lose weight become confused as to which is the best strategy to follow. Last year the Atkins diet was in fashion and carbohydrates were to be avoided at all cost. This year the tables have turned and it is the GI diet that is hitting the headlines, where carbohydrates are allowed - as long as they have a low glycaemic index. Although the GI diet is an improvement on the Atkins diet, a recent study reported that there was no difference in reduction of bodyweight between a low glycaemic index and high glycaemic index diet after 10 weeks.  Researchers concluded that the results did not support the contention that low-fat, low-GI diets were more beneficial than high-GI diets with regard to appetite or bodyweight regulation.(5)
As health professionals, it is our responsibility to offer dietary advice that is evidence-based and shown to be effective in the long term. It is true that people lose weight on fad diets, but compliance in the long term is poor and they are much less effective in maintaining the weight loss, resulting in weight cycling. In addition, one of the common characteristics of a fad diet is the exclusion of certain foods or food groups, resulting in a nutritionally unbalanced diet.
A recent systematic review of the long-term benefits of weight-reducing trials in adults confirmed that low-fat diets are the most effective.(6) This review found that low-fat diets produced significant weight losses up to 36 months, and concluded that there was little evidence to support the use of other diets, such as low-carbohydrate diets, for weight reduction.
The evidence is clear that following a reduced- energy diet that is low in fat and high in carbohydrates is the most effective approach to weight loss. This is largely due to the fact that the energy contained in 1g of fat (9kcal) is more than twice that contained in either carbohydrate (3.75kcal) or protein (4.0kcal). In addition, fatty foods tend to be very palatable foods, which promotes an overconsumption of energy. Reducing the content of fat in the diet by removing the energy-dense, fatty foods will result in a bulkier, more satiating diet that is lower in energy. In fact, advice to reduce fat alone without consciously restricting energy intake can result in a spontaneous weight loss of 2-3 kg.(7)  
A low-fat, high-carbohydrate diet, where the carbohydrate consisted of a mixture of starch or sugar, has also been shown to be effective for weight loss in a large pan-European study in 2000.(8) This study compared subjects consuming a diet that was low in fat and high in carbohydrate (starch and sugar) with subjects consuming a diet low in fat and high in starchy carbohydrates only. There was no difference in weight loss between the groups, and it was concluded that it was not necessary to exclude sugars from a weight-reducing diet. In fact, it may be beneficial to include some simple carbohydrates into a low-fat diet to improve the palatability of the diet. There tends to be an inverse relationship between sugar and fat in the diet - where individuals achieving a low-fat diet have higher intakes of sugar than those consuming a high-fat diet.(9) Not surprisingly, those consuming a low-fat diet tend to be leaner than the high-fat consumers.

What practical advice can health professionals offer?
In terms of practical dietary advice for the obese patient, the health professional has to give advice that is not only based on evidence but is realistic for the patient (see Table 1). There is no point advising the patient to radically change their diet, since compliance would be poor. Small changes in the right direction over the long term are more beneficial than radical changes that last just two weeks. Small changes are easier to incorporate into the diet, and it is vital these changes are acceptable and agreed upon by both the health professional and the patient.

[[NIP25_table1_66]]

Changes to cooking methods may be a good place to start. Encourage the patient to avoid frying, or to use spray oil when stir-frying. Trimming meat of all fat, choosing leaner cuts of meat and avoiding high-fat meat products such as meat pies, sausages and burgers would significantly reduce intakes of fat. Examples of substitutions are helpful - boiled or baked potatoes instead of chips; a sandwich with lean ham and tomato or chicken salad instead of cheese or mayonnaise-based filling; reduced-fat milk instead of whole milk; low-fat yogurt as a dessert instead of ice cream (see Table 2). In addition, it is also important to emphasise the foods that the patient does not need to restrict and may benefit from eating more of - all fresh, dried or tinned fruits, and all fresh, frozen or tinned vegetables.

[[NIP25_table2_68]]

Portion sizes must also be considered if the total energy intake is to be reduced, and it may be more acceptable for the individual to eat small meals more frequently, rather than leave long gaps between larger meals. Low-fat high-carbohydrate snacks could be suggested, such as a small fruit scone or a bagel with a thin spread of jam, a handful of dried fruits, low-fat yogurt, a small fruit juice, pretzels, Twiglets, low-fat biscuits and cereal bars, as opposed to higher-fat snacks such as crisps or chocolate. However, it is worth remembering that cutting out a favourite food altogether, for example chocolate, is likely to lead to more severe relapses than including that food in moderation.

Activity advice for the obese patient
Maintaining a healthy weight is a balancing act between energy intake and energy expenditure. To lose weight we must use up more energy than we consume. Therefore one way to promote weight loss is to increase our activity levels. The recommended activity level for weight loss is 60 minutes of moderate activity most days.(3) This may appear daunting for the obese patient, but it should be explained to them that this could be made up of three 20-minute walks (one before work, one at lunchtime and one after work). It becomes more realistically achievable for the patient if it can be worked into the individual's lifestyle. Combining exercise with an energy-restricted diet is more effective in producing weight loss than either diet alone or exercise alone. In addition, it has been shown to improve weight maintenance long term - that is, those individuals who exercise are more successful at keeping the weight off than those who do not exercise. This may be important for those who have previously experienced weight cycling.(10)
Again, it is important for the health professional to agree goals that are acceptable to the individual. It may be that they start by including an extra 20 minutes of activity into their daily routine, increasing gradually to the recommended 60 minutes over a few weeks. Also, activity suggestions could include gardening, walking the children to school, or walking part of the way to work, or taking up a more structured form of exercise such as a dance class, or even washing the car by hand instead of taking it through the car wash. It may be prudent to have to hand a list of Local Authority activities that are either free to use or inexpensive. However, if the patient does not feel comfortable exercising in public, home-based activities should be suggested. 

Conclusion
There may not be one definitive weight loss strategy to suit all, but as health professionals it is our responsibility to advise the patient on the strategy that is most likely to be effective based on scientific evidence. It may be that the individual makes small adaptations to fit in with their lifestyle, likes and dislikes, but the goal is to motivate the patient to select a weight loss regime that is practicable and sustainable, so that weight loss is achieved slowly and safely, while also incorporating beneficial lifestyle changes beyond the initial weight loss period.(11)

References

  1. National Diet and Nutrition Survey: Adults aged 19-64 years. Available from URL: http://www.statistics.gov.uk/ssd/surveys/national_diet_nutrition_survey_...
  2. Joint Health Surveys Unit on behalf of the Department of Health. Health Survey for England 2001. London:The Stationery Office; 2002.
  3. World Health Organization. Report of a joint FAO/WHO on diet, nutrition and prevention of chronic diseases. WHO Technical Report Series 916. Geneva: WHO; 2003.
  4. Lean ME. Clinical handbook of weight management. London: Martin Dunitz; 1998.
  5. Sloth B, Krog-Mikkelsen I, Flint A, et al. No difference in body weight decrease between a low-glycaemic index and high-glycaemic index diet but reduced LDL cholesterol after 10 wk ad libitum intake of the low-glycaemic index diet. Am J Clin Nutr 2004;80(2)337-47.
  6. Avenell A, Brown TJ, McGee MA, et al. What are the long-term benefits of weight reducing diets in adults? A systematic review of randomised controlled trials. J Hum Nutr Diet 2004;17(4):317-35.
  7. Astrup A, Astrup A, Buemann B, et al. Low-fat diets and energy balance: how does the evidence stand in 2002? Proc Nutr Soc 2002;61(2):299-309.
  8. Saris WH, Astrup A, Prentice AM, et al. Randomised controlled trial of changes in dietary carbohydrate/fat ratio and simple vs. complex carbohydrates on body weight and blood lipids: the CARMEN Study. Int J Obes Relat Metab Disord 2000;24(10):1310-8.
  9. Bolton Smith C, Woodward M. Dietary composition and fat to sugar ratios in relation to obesity. Int J Obes Relat Metab Disord 1994;18(12):820-8.
  10. Field AE, Manson JE, Taylor CB, et al. Association of weight change, weight control practices and weight cycling among women in the Nurses' Health Study II. Int J Obes Relat Metab Disord 2004;28(9):1134-42.
  11. Scottish Intercollegiate Guidelines Network. Obesity in Scotland:integrating prevention with weight management. Edinburgh: SIGN; 1996.

Resources
European Association for the Study of Obesity
W:www.easo
obesity.org

British Nutrition Foundation
W:www.nutrition.org.uk

Further reading
World Health Organization. Obesity:
preventing and managing the global epidemic. Geneva: WHO; 2000

British Nutrition Foundation. Obesity: report of a British Nutrition Foundation task force. Oxford: Blackwell Science; 1999