Causes and Factors Influencing Obesity
CHAPTER ONE
PREAMBLE TO THE STUDY
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
CHAPTER TWO
CAUSES AND FACTORS INFLUENCING OBESITY
CAUSES OF OBESITY
Although the mechanism of obesity development is not fully understood, it is confirmed that obesity occurs when energy intake exceeds energy expenditure. There are multiple etiologies for this imbalance, hence, and the rising prevalence of obesity cannot be addressed by a single etiology.
Genetic factors influence the susceptibility of a given child to an obesity-conducive environment. However, environmental factors, lifestyle preferences, and cultural environment seem to play major roles in the rising prevalence of obesity worldwide (Hill and Peters, 1998; Goodrick et al., 1996; Eckel and Krauss, 1998). In a small number of cases, childhood obesity is due to genes such as leptin deficiency or medical causes such as hypothyroidism and growth hormone deficiency or side effects due to drugs (e.g. – steroids) (Link et al., 2004). Most of the time, however, personal lifestyle choices and cultural environment significantly influence obesity.
Behavioral and social factors
Diet
Over the last decades, food has become more affordable to larger numbers of people as the price of food has decreased substantially relative to income and the concept of ‘food’ has changed from a means of nourishment to a marker of lifestyle and a source of pleasure. Clearly, increases in physical activity are not likely to offset an energy rich, poor nutritive diet. It takes between 1–2 hours of extremely vigorous activity to counteract a single large-sized (i.e., >=785 kcal) children’s meal at a fast food restaurant. Frequent consumption of such a diet can hardly be counteracted by the average child or adult (Styne et al., 2005).
Calorie intake: Although overweight and obesity are mostly assumed to be results of increase in caloric intake, there is not enough supporting evidence for such phenomenon. Food frequency methods measure usual diet, but estimate caloric intake poorly (Willett, 1998). Other methods such as 24-hour recall or food diaries evaluate caloric intakes more accurately, however, estimate short-term not long-term intake (Willett, 1998).
Total energy intake is difficult to measure accurately at a population level. However, a small caloric imbalance (within the margin of error of estimation methods) is sufficient over a long period of time to lead to obesity. An increase calorie intake only among white and black adolescent females was previously observed in USA. The same pattern was observed by the latest NHANES (1999– 2000). The Bogalusa study which has been following the health and nutrition of children since 1973 in Bogalusa (Louisiana), reported that total calorie intake of 10-year old children remained unchanged during 1973–1988 and a slight but significant decrease was observed when energy intake was expressed per kilogram body weight (Nicklas, 1995). The result of a survey carried out during the past few decades in the UK suggested that average energy intakes, for all age groups, are lower than they used to be (Nicklas, 1995). Some small studies also found similar energy intake among obese children and their lean counterparts (Griffiths and Payne, 1976; Bellisle et al., 1988; Maffeis et al., 1996; Kelishadi et al., 2003).
CHAPTER THREE
PREVENTION OF OBESITY
Almost all public health researchers and clinicians agree that prevention could be the key strategy for controlling the current epidemic of obesity (Muller et al., 2001). Prevention may include primary prevention of overweight or obesity itself, secondary prevention or avoidance of weight regains following weight loss, and prevention of further weight increases in obese individuals unable to lose weight. Until now, most approaches have focused on changing the behavior of individuals on diet and exercise and it seems that these strategies have had little impact on the growing increase of the obesity epidemic. Children are often considered the priority population for intervention strategies because, firstly, weight loss in adulthood is difficult and there are a greater number of potential interventions for children than for adults. Schools are a natural setting for influencing the food and physical activity environments of children. Other settings such as preschool institutions and after-school care services will have similar opportunities for action. Secondly, it is difficult to reduce excessive weight in adults once it becomes established. Therefore it would be more sensible to initiate prevention and treatment of obesity during childhood. Prevention may be achieved through a variety of interventions targeting built environment, physical activity and diet.
CHAPTER FOUR
CONCLUSION AND RECOMMENDATIONS
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.
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.
REFERENCES
- Barker, D. J. P (1995). Fetal origins of coronary heart disease. Br. Med. J. 311, 171–174
- Barker, D. J. P 1989). Growth in utero, blood pressure in childhood and adult life, and mortality from cardiovascular disease. Br. Med. J. 298, 654–657
- Bellisle F, Rolland-Cachera MF, Deheeger M, Guilloud-Bataille M (1988). Obesity and food intake in children: evidence for a role of metabolic and/or behavioral daily rhythms. Appetite, 11:111-118.
- Bennett, N., Dodd, T., Flatley, J., Freeth, S. & Bolling, K (1995) Health Survey for England 1993.
- Blundell J. E. & Macdiarmid, J. I (1997). Passive overconsumption: fat intake and short term energy balance. Ann. NY Acad. Sci. 827, 392–407.
- Bouchard, C (1990). The response to long term overfeeding in identical twins. N. Engl. J. Med. 322, 1477–1482
- Campbell K, Crawford D, Jackson M, Cashel K, Worsley A, Gibbons K, Birch LL (2002). Family food environments of 5-6-year-old-children: does socioeconomic status make a difference? Asia Pac J Clin Nutr, 11 Suppl 3:S553-S561.
- Campfield, L. A., Smith, F. J., Guisez, Y., Devos, R. & Burn, P (1995). Recombinant mouse ob protein: evidence for a peripheral signal linking adiposity and central neural networks. Science 280, 546–549
- Carriere G (2003). Parent and child factors associated with youth obesity. Statistics Canada
- Carruth BR, Skinner JD (2001). The role of dietary calcium and other nutrients in moderating body fat in preschool children. Int J Obes Relat Metab Disord 25:559-566.
- Caterson ID, Gill TP (2002). Obesity: epidemiology and possible prevention. Best Pract Res Clin Endocrinol Metab 16:595-610.
- Chan, J. M (1994). Obesity, fat distribution and weight gain as riskfactors for clinical diabetes in men. Diabetes Care 17, 961–969 .
