Obesity

Medical and Health Science Project and Seminar Material

Obesity

Chapter One

1.0 Introduction

1.1 Obesity

Obesity can be defined as an excess of Body Fat (BF). There is no consensus on a cutoff point for excess fatness of overweight or obesity in children and adolescents. Obesity is now so common within the world’s population that it is beginning to replace undernutrition and infectious diseases as the most significant contributor to ill health. In particular, obesity is associated with diabetes mellitus, coronary heart disease, certain forms of cancer, and sleep-breathing disorders (Caterson and Gill, 2002).

Obesity is defined by a body-mass index (weight divided by square of the height) of 30 kg m–2 or greater, but this does not take into account the morbidity and mortality associated with more modest degrees of overweight, nor the detrimental effect of intra-abdominal fat (Chan, 1994). The global epidemic of obesity results from a combination of genetic susceptibility, increased availability of high-energy foods and decreased requirement for physical activity in modern society. Obesity should no longer be regarded simply as a cosmetic problem affecting certain individuals, but an epidemic that threatens global well-being (Caterson and Gill, 2002).

Obesity causes or exacerbates many health problems, both independently and in association with other diseases. In particular, it is associated with the development of type 2 diabetes mellitus, coronary heart disease (CHD), an increased incidence of certain forms of cancer, respiratory complications (obstructive sleep apnoea) and osteoarthritis of large and small joints (Styne et al., 2005).

There are also several methods to measure the percentage of body fat. In research, techniques include underwater weighing (densitometry), multi-frequency bioelectrical impedance analysis (BIA) and magnetic resonance imaging (MRI). In the clinical environment, techniques such as body mass index (BMI), waist circumference, and skin fold thickness have been used extensively. Although, these methods are less accurate than research methods, they are satisfactory to identify risk (Caterson and Gill, 2002; Styne et al., 2005).

Table 1 – Cut-off points proposed by a WHO expert committee for the classification of overweight

*BMI (kg m–2)**	WHO classification	Popular description
<18.5	Underweight	Thin
18.5–24.9	____	‘Healthy’, ‘normal’, ‘acceptable’
25.0–29.9	Grade 1 overweight	Overweight
30.0–39.9	Grade 2 overweight	Obesity
≥40.0	Grade 3 overweight	Morbid obesity

*BMI is the weight in kilograms divided by the square of the height in metres.

The data presented in Tables 1 and 2 reflect knowledge acquired largely from epidemiological studies in developed countries. Preliminary information from developing nations indicates that lower cut-off levels for both BMI and waist circumference (see Table 2) are necessary for certain populations who are at particular risk from comparatively modest degrees of overweight.

Source: Peter, 2000

Table 2 – Waist circumference predicts risk of metabolic complications

	Increased risk	Substantially increased risk
Men	≥94 cm	≥102 cm
Women	≥88 cm	≥88 cm

Gender-specific waist circumferences are presented that denote ‘increased risk’ (level 1) and‘substantially increased risk’ (level 2) of metabolic complications associated with obesity in Caucasians. Level 1 is intended to alert clinicians to potential risk for CHD whereas level 2 should initiate therapeutic action

Source: Peter, 2000

While BMI seems appropriate for differentiating adults, it may not be as useful in children because of their changing body shape as they progress through normal growth. In addition, BMI fails to distinguish between fat and fat-free mass (muscle and bone) and may exaggerate obesity in large muscular children (Eckel and Krauss, 1998).While health consequences of obesity are related to excess fatness, the ideal method of classification should be based on direct measurement of fatness. Although methods such as densitometry can be used in research practice, they are not feasible for clinical settings (Chan, 1994).

Chapter Four

4.0 Conclusion And Recommendations

4.1 Conclusion

Obesity is a chronic disorder that has multiple causes. Overweight and obesity in childhood have significant impact on both physical and psychological health. In addition, psychological disorders such as depression occur with increased frequency in obese children. Overweight children are more likely to have cardiovascular and digestive diseases in adulthood as compared with those who are lean. It is believed that both over-consumption of calories and reduced physical activity are mainly involved in childhood obesity.

Apparently, primary or secondary prevention could be the key plan for controlling the current epidemic of obesity and these strategies seem to be more effective in children than in adults. A number of potential effective plans can be implemented to target built environment, physical activity, and diet. These strategies can be initiated at home and in preschool institutions, schools or after-school care services as natural setting for influencing the diet and physical activity and at home and work for adults. Both groups can benefit from an appropriate built environment.

4.2 Recommendations

Obesity is arguably the biggest challenge among the epidemics facing the world because it is on the rise in low and high income countries, no country has a track record in terms of attenuating and reversing the epidemic, and it has several major downstream health consequences in terms of diabetes, cardiovascular diseases, some cancers and arthritis that are very common and expensive to treat.

It is highly recommended to improve the methods for measuring body composition, dietary intake, physical activity in populations. Also maintaining and enhancing systems for monitoring trends in overweight/obesity, nutrition and physical activity and their environmental determinants should be put in place.