Weight Management

A Practitioner's Guide

Dympna Pearson, Clare Grace

• Editorial: Wiley-Blackwell
• Año: 2012
• ISBN:
  9781118343326
• Edición: 1
• Categoría: Medicine
• Categoría: Nutrition, Dietics & Bariatrics

Weight Management

A Practitioner's Guide Dympna Pearson and Clare Grace

Amid an alarming rise in the prevalence of obesity, there has been a similar rapid expansion in the theory and evidence base surrounding its management but limited detail on the practical application of lifestyle treatments. This exciting new book provides practitioners and those studying to become healthcare professionals with a much-needed modern guide which clearly presents the latest evidence underpinning obesity interventions and how to deliver these in practice.

Written by renowned experts Dympna Pearson and Clare Grace, the book is intended as a ready reference for those working in both acute and community settings throughout the different and demanding stages of the weight management process. It explains how effective evidence-based programmes, structured to address the key components of diet and physical activity and integrated with a behavioural approach, can achieve improved outcomes. Bringing together evidence of best practice, it considers in detail the practical application of these approaches and provides clear answers to frequently encountered challenges.

Key Features

• A practical guide to tackling weight management
• Primary focus on lifestyle interventions in adults covering diet, exercise and behavioural therapy
• Step-by-step framework of care for overweight and obese individuals

Related Titles

Textbook of Obesity: Biological, Psychological and Cultural Influences
Edited by Sharon Akabas, Sally Ann Lederman and Barbara J. Moore
ISBN: 978-0-470-65588-7

Food and Western Disease: Health and Nutrition from an Evolutionary Perspective
Staffan Lindeberg
ISBN: 978-1-4051-9771-7

1

Background Information

1

Why Treat Obesity?

‘Obesity poses a threat on a similar scale to climate change’ [1]

What is the scale of the obesity problem?

Obesity is one of the most serious and complex health challenges faced by the UK, Europe and most of the rest of the world. There has been a dramatic doubling in its prevalence over the last 25 years with most adults in England now overweight, and 1 in 4 obese (24% men; 25% women) [2]. Alarmingly similar trends have been observed in children, with 14.4% of 2–10 year olds obese in 2009 [3]. If current trends continue, future prevalence predictions are dire, with suggestions that 9 in 10 adults in England could be obese by 2050 [4].

This will have profound cost implications for the NHS and the wider economy. Current estimates for the NHS suggest obesity costs £4.2 billion/year, with wider economic costs (reduced productivity, loss of earnings, increased benefits) of £16 billion/year. If future prevalence predictions are accurate, this may rise to £10 billion/year and £50 billion/year, respectively [4].

A strong social inequality exists in the prevalence of obesity, although the factors responsible are unclear: in men, 18% are obese in social class I versus 28% in social class V; in women, 10% are obese in social class I versus 25% in social class V [5]. Unfortunately, there is limited information on whether prevalence varies by ethnicity as most surveys only include small numbers from various ethnic groups. However, in 2004, a higher prevalence of obesity was found in black African, black Caribbean and Pakistani women compared to the general population [6].

Why does it matter?

Obesity is known to shorten life, is a risk factor for a range of major co-morbidities and can have profound effects on an individual’s psychological and social well being. There are also wider economic and social consequences for society that make addressing obesity a compelling, albeit challenging, issue.

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Obesity shortens life

Up to 13 years of life can be lost in obese men and up to 8 years in obese women [7]

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Obesity and early death

Obesity increases the risk of dying early, particularly in men. In young adults there is a 50% greater risk of early death in those with body mass index (BMI) above 30 kg/m² compared to healthy-weight individuals [8]. Over the years there has been debate on the precise relationship between mortality risk and obesity. However, after appropriate adjustment for confounders, an elevated BMI is clearly linked with increased risk of premature death [9–11]. Obese white men aged 20–30 years with a BMI greater than 45 kg/m² are likely to lose 13 years of their life and for women with similar characteristics this can be up to 8 years [7]. The link between mortality risk and BMI is greatest up to the age of 50 but does continue through to old age [12]. Risk can be moderated depending on the level of physical fitness, with suggestions that being overweight and inactive may account for up to 31% of early all-cause mortality [13].

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Diabetes risk

Rapid rise above BMI 25 kg/m²

Longer obesity duration = greater diabetes risk

Even small increases in weight increase risk

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Obesity and type 2 diabetes

Of all the associated co-morbidities, type 2 diabetes is the most strongly linked. Increasing fat mass, particularly abdominal/visceral obesity, is well recognised as a risk factor for the development of type 2 diabetes, due to its contribution to insulin resistance and beta cell dysfunction. The BMI above which diabetes risk begins to rise rapidly is surprising low, with a 3.6-fold greater risk in women with a BMI of 23–24 kg/m² compared to those with a BMI <22 kg/m², highlighting that this association is not the sole reserve of the severely obese [14]. For those aged 40–49 years with BMI >35 kg/m², risk of developing diabetes has been found to be almost 80 times higher than in those with a BMI of <22 kg/m² [15].

The longer the duration of obesity and weight gain, the higher the level of risk, with a 3-fold elevated risk in those who have been overweight for less than 5 years versus a 5-fold risk in those who have been overweight for more than 5 years [16]. Several studies have shown that individuals with small weight gains in early adulthood of ~5–8 kg have twice the risk of diabetes compared to those who have minimised weight gain [15,17], emphasising the importance of preventing weight gain.

The risk of diabetes varies by ethnicity and is especially high in those of Asian origin. For each 5 kg weight gain, the risk of diabetes increased by 37% in whites, 38% in blacks but 84% in Asians.

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Weight gain of 5 kg increases diabetes risk by 84% in Asians versus 37% in whites

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Obesity and cancer

A BMI of ≥40 kg/m² has been associated with a 50–60% increased chance of developing cancer compared to healthy-weight individuals [9]. Obesity has been specifically implicated in cancer of the colon, endometrium and breast. A 1.5-fold greater risk of developing colorectal cancer has been found in women with a BMI greater than 29 kg/m² and in men with abdominal obesity (waist–hip ratio, WHR ≥ 0.99) [18,19]. Dietary factors (red and processed meats may exacerbate, while fibre and n-3 PUFA may protect) and physical inactivity (high activity levels may protect) have also been linked to the risk of colon cancer.

Obesity and cardiovascular disease

Obesity is a major modifiable risk factor for coronary heart disease. Its association with various atherogenic lipid and lipoprotein abnormalities is well recognised, including elevated total cholesterol and triglyceride, and lowered high-density lipoprotein cholesterol [20]. It is this link with atherogenesis, together with its negative impact on other coronary risk factors (hypertension, type 2 diabetes), that explains the strong positive association between the incidence of coronary heart disease and obesity [21]. It has been estimated that as much as 70% of the coronary heart disease in obese women is attributable to overweight [22]. The distribution of adipose tissue is also known to be important, with central obesity increasing metabolic risk via a greater predisposition to dyslipidemia [23].

Quality of life

Research clearly illustrates that obesity has an adverse effect on health-related quality of life, with the magnitude of impairment increasing with increasing severity of obesity [24]. Conversely, improvements are reported after weight loss, although most research has explored changes after surgery rather than changes related to lifestyle approaches [25]. Obesity affects many aspects of physical and social functioning, sexual function and satisfaction, public distress and the ability to engage fully in the workplace.

Whether obesity leads to or is a consequence of depression has been hotly debated and there is a need for greater understanding of this complex relationship. A recent meta-analysis concluded that depression and obesity were reciprocal, with an increased risk of depression in the obese, and with depression being predictive for obesity [26].

Factors that increase the risk of obesity

Smoking cessation

Giving up smoking is commonly associated with an average weight gain of 7 kg [27], although this varies by age, lifestyle behaviours and socioeconomic status. There are a number of possible reasons for this link, including: the removal of the appetite suppressing effect of nicotine; an improved sense of taste and smell leading to altered food preferences; swapping oral gratification from smoking to food; and behaviourally using food in the same way as cigarettes – for example, to deal with stress, boredom, self-rewards or as a means of socialising.

Although over 80% of those quitting smoking will gain weight, the health benefits of smoking cessation far outweigh the health risks of gaining weight.

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To reach the same health risk as smoking one packet of cigarettes a day, the average smoker would need to be 55 kg overweight

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As the evidence currently stands, the optimal timing of weight management and quit attempts is unclear. There is some concern that trying to control weight through lifestyle interventions while trying to quit smoking may negatively impact on the success of smoking cessation. Until it is clear that concurrent weight management does not lead to an increase in quit failure it may be wise to reserve weight-­management interventions until smoking cessation has been successfully ­completed. However, there may be instances when an individual is so concerned about the possibility of weight gain that it adversely affects their motivation to stop smoking. Such situations require clinical judgment to determine whether individualised weight management alongside smoking cessation would be beneficial.

The provision of general advice ‘to avoid gaining weight’ while trying to quit smoking is generally ineffective and may hinder smoking cessation attempts. However, individualised weight-management interventions limit the extent of weight gain during the smoking cessation period, although the effect is small. The use of cognitive behavioural therapy and very low-calorie diets alongside smoking cessation treatments may be beneficial in reducing post-cessation weight gain. Longer-term studies are required and it is recommended that these strategies are reserved for use in research settings [27].

The role of physical activity in managing weight during and after smoking cessation is a little unclear, although it may be important for improved weight control over the longer term [27,28].

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Just advising people planning to stop smoking to avoid gaining weight is unhelpful and may prevent the attempt to quit.

There is insufficient evidence to determine the optimal timing of weight-management interventions and smoking cessation.

It may be most prudent to wait until after a successful quit attempt has been completed before considering weight-management interventions.

The decision to offer individualised weight-management interventions concurrently with a quit attempt should be made on an individual basis using clinical judgment.

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Certain medications

There are certain medications known to increase the risk of weight gain and some of those listed below have been associated with up to a 10 kg gain over 12 weeks [29]. It may be helpful to discuss weight-management options in instances where the prescribing of such medications is necessary and an alternative is not suitable.

• atypical antipsychotics, including clozapine;
• beta adrenergic blockers, particularly propranolol;
• insulin, when used in the treatment of type 2 diabetes mellitus;
• lithium;
• sodium valproate;
• sulphonylureas, including chlorpropamide, glibenclamide, glimepiride and glipizide;
• thiazolidinediones, including pioglitazone;
• tricyclic antidepressants, including amitriptyline.

To date there is no evidence to suggest a link between oral combined contraceptives or hormone replacement therapy and weight gain [30].

Obesity and its causes

Obesity is commonly misconstrued as a self-inflicted condition, the causes of which are simple: eating too much and exercising too little. This is far removed from the complex nature of obesity revealed by science, and such misunderstandings tend to fuel weight-related stigma and do little to enhance obesity treatments.

Why do practitioners need a good understanding of obesity causes?

Developing a broad understanding of the complex biological and environmental factors involved in the development of obesity may have a number of important benefits:

1 Positive impact on the practitioner’s at...