Physiological Effects Of Obesity - Essay

Measuring body shape can be a rich data about health and the risk of disease. Measuring anthropometry manually could be time-consuming, only a few indexes of shape (e.g. body girths and their ratios) are used regularly in clinical practice or epidemiology, both of which still rely primarily on body mass index (BMI). Three-dimensional (3-D) body scanning provides high-quality digital information about shape.

Obesity, on the other hand, is the accumulation of excess body fat, whereby a sizeable amount of adipose tissue goes untapped. Obesity results from the imbalance between energy intake and energy expenditure. This imbalance may be the result, individually or concomitantly, of excess caloric intake, decreased physical activity, metabolic disorders, and genetics (National Institutes of Health, 1998; Berg, 1993). Genetics are seen to influence whether an individual can become obese, while environment determines whether the individual actually does become obese, as well as the extent of the obesity (Meyer & Stunkard, 1993).Obesity is a health disorder in which a person gains at least 20% of the usual body weight because of the increase in the fat cells (adipose tissues) in the body. This accumulation of excess fat causes serious threat to health. The adverse health conditions can lead to various physical and emotional problems. These include cardiac diseases, high pressure and even different forms of cancers, apart from depression and diabetes.

In recent times, obesity has become one of the vital health problems in the society. According to estimates, there are more than 1 billion obese people in the world.

Generally, faulty food habits, excess intake of food and hormonal imbalance are the main causes of this disorder.

1.2 Symptoms of Obesity

a) Excessive weight within a short period of time. He/she usually gains 4-5 kilos every month, such that the metabolism process becomes difficult to control.

b) The chest area tends to look larger, especially in men as the body fat starts getting accumulated in that area at the initial stage. In women, fat gets accumulated in the waists, thigh, upper arms and breasts. This is a major symptom of obesity.

c) The size of the abdomen tends to enlarge. At times, there are whitish marks on the abdomen areas due to the excess accumulation of fatty tissues.

d) Another preliminary symptom is that the person tends to have shortness of breath. He cannot breathe properly because of the accumulation of excess fat in the chest area and below the diaphragm.

e) Most people start suffering from indigestion due to an excess of abdominal fat. At the same, time, Urinary incontinence or urine leakage happens, mostly to women. Although most of this underreported, this can be taken as a serious symptom of obesity. Abdominal obesity is also marked by symptoms such as snoring and sleeps disturbances.

f) One of the scientific ways of understanding obesity is by calculating the body mass index (BMI). It is the ratio of the person’s height to weight. According to the World Health Organization, if the BMI is in the range of 25-29, a person is overweight and if the BMI is 30 and above, the person is considered to be obese.

1.3 Effects of obesity on human body

The effects of obesity extend far beyond physical weight and related health problems. Obesity side effects can include a greater risk of mental health problems and low self-esteem. Social attitudes on obesity range from avoidance to outright discrimination and bullying.

The effects of obesity on physical health are well documented. The Stanford Hospital (2010) reports obesity causes up to 300,000 premature deaths a year in the United States alone. Obesity health effects range from backaches and joint pain to life-threatening conditions. The following is a list of health conditions attributed to obesity. This list is by no means exhaustive; the effects of obesity on physical health care, unfortunately, many and varied.

Physical disorders

Obesity can cause serious physical disorders. It may lead to chronic diseases, disability and eventually death if not treated correctly and at the right time. Let us examine some of the physical effects of obesity.

Decreased mobility – It becomes difficult for obese people to move around. They often feel tired and breathless as they have much accumulation of fat in the chest, neck and associated areas of the body. There is a constant feeling of breathlessness and fatigue, which leads lack of activity and movement.

Cardiac disease – People who are obese generally have frequent chest pains and higher risks of heart attack. Congestive heart failure is also common for such people. At the same time, it is common for obese people to have high blood pressure compared to those who maintain a healthy body weight.

Cancer – It has been observed that obese people have an increased risk of certain cancers. These include cancers of the gall bladder, uterus, colon, prostrate and kidney, among others. Obese women are more prone to breast cancers in their mid-lives.

Arthritis – Obesity is strongly associated with joint pain and arthritis. It is common for obese men and women to have osteoarthritis, which is a joint disorder, causing ache and inflammation especially in areas such as lower backs, waists and knees.

1.4 Measurement of Obesity

BMI is a measurement of body weight based on height and weight. Although BMI does not actually “measure” percentage of body fat, it is a useful tool to estimate a healthy body weight based on height. Due to its ease of measurement and calculation, it is the most widely used diagnostic indicator to identify a person’s optimal weight depending on his height. BMI “number” will inform one if one is underweight, of normal weight, overweight, or obese. However, due to the wide variety of body types, the distribution of muscle and bone mass, etc., it is not appropriate to use this as the only or final indication for diagnosis. In adults, a BMI of 25 to 29.9kg/m2 means that person is considered to be overweight, and a BMI of 30kg/m2 or above means that person is considered to be obese.

The use of BMI as a measure of body composition has met with some criticism (Blew, et al., 2002; Duerenberg, Yap & van Staveren, 1998; Gallagher, et al., 1996; Prentice & Jebb, 2001). Clinical and laboratory studies often employ more sophisticated measures of body composition and distribution, such as: measures of electrical impedance; underwater weighing; or circumference measures determining fat distribution via a waist to hip ratio. While these measures allow for a very detailed examination of body composition, they require specialized equipment and training to collect, and are not practical for large surveys. Notwithstanding, BMI has shown to be a relatively strong metric for body composition. Recent studies show that electrical impedance is not superior to BMI as a predictor of overall adiposity (Willett, et al., 2006) and in clinical samples, Ensrud and colleagues (1994) found the relationship between BMI and functioning to be stronger than that for waist to hip ratio and functioning.

1.5 BMI Table for Adults

This is the World Health Organization’s (WHO) recommended body weight based on BMI values for adults. It is used for both men and women, age 18 or older.

Category

BMI range – kg/m2

Severely underweight < 16.5

Underweight 16.5 – 18.5

Normal 18.5 – 25

Overweight 25 – 30

Obese Class I 30 – 35

Obese Class II 35 – 40

Obese Class III > 40

1.7 Ethnicity

Analyses have revealed significant differences in size and body shape between ethnic groups and social categories within the US population, and have further demonstrated significant differences in body shape between US and UK white adults. These differences may prove to play a key role in accounting for differences in morbidity and mortality between these populations and social groups. (Table1.2)

Table 1.2 Body shape in American and British adults: between country and inter-ethnic comparisons

Comments

Wells et al. (2007)

Adults17+ yrs from UK (3907M and 4710F white), and from USA (1744M and 3329F, 709M and 1106F African and 639M and 839F Hispanic).

Two National Sizing Surveys, SizeUK and SizeUSA, were conducted using identical instrumentation, study design and recruitment strategy.

All Outcomes (except height) adjusted for height P< 0.01; P < 0.0001.

In USA, socio-economic status was associated with increasing height and decreasing waist girth in white and Hispanic, but not African Americans. Compared to white British, white Americans had larger weight and girths, especially waist girth in men.

Long Study population, some subjects may withdraw before the end of study, Lynch et al. (2006)

5,115, by ethnicity (Black/White), sex, age (18-24years/25-30 years).

Body size judgments were obtained using the Stunkard figure rating scale.

Black men (p < 0.05) and 1.48 vs. 0.96 for White women vs. Black women (p < 0.0001)).

Black men were slightly younger, and had higher BMIs than White participants.

Stunkard scale was for White persons, may not be good for Black persons.

Pepper et al (2010) 70 women evaluated for waist and hip circumference and waist: hip ratio via laser scanner and tape measure.

In a subset of 34 participants, 8 repeated measures of laser scanning were performed for reproducibility analysis.

Interclass correlation coefficient .992, p < 0.01.

Evaluation of waist and hip circumferences measured by body scanning did not differ significantly from tape measure (p > 0.05).

Small study population

1.8 Causes of Obesity

Obesity does not just happen overnight, it develops gradually from poor diet and lifestyle choices and, to some extent, from ones genes (the units of genetic material inherited from ones parents).

Lifestyle choices are an important factor in influencing your weight. Eating more calories than you need may be down to unhealthy food choices. For example, unhealthy food choices could be:

• eating processed or fast food that is high in fat,
• not eating fruit, vegetables and unrefined carbohydrates, such as wholemeal bread and brown rice,
• drinking too much alcohol – alcohol contains a lot of calories, and heavy drinkers are often overweight, and
• eating out a lot – as you may have a starter or dessert in a restaurant, and the food can be higher in fat and sugar,
• eating larger portions than you need – you may be encouraged to eat too much if your friends or relatives are also eating large portions, and
• comfort eating – if you feel depressed or have low self-esteem you may comfort eat to make yourself feel better.

Lack of physical activity is another important factor that is related to obesity. Many people have jobs that involve sitting at a desk for most of the day, and rely heavily on their cars to get around. When it is time to relax, people tend to watch TV, or play computer games, and rarely take any regular exercise. If you are not active enough, you do not use up the energy provided by the food you eat, and the extra calories are stored as fat instead.

Some people tend to stay the same weight for years without much effort, whereas others find they put on weight quickly if they are not careful about what they eat. This could be due, in part, to your genes. Some genetic conditions can increase your appetite, so you end up eating too much. There are also genes that determine how much fat your body stores. A particular genetic variation could mean that your body is more likely to store fat than somebody else.

1.9 Patterns of Obesity in the Population

The composition of the body and how fat is stored changes with age, and different metabolic and hormonal factors influence body fat accumulation throughout the life spectrum (Schwartz, 1995; Beaufrere & Morio, 2000). In cross-sectional studies, peak values of BMI are observed in the age range 50-59 in both men and women, with gradual declines in BMI after age 60 (Flegal, et al., 1998; Hedley, et al., 2004;), although premature mortality of the obese may influence these cross-sectional relationships (Williamson, 1993). Rates of overweight and obesity in longitudinal studies generally increase with age until age 75, when there is a small drop (Flegal, et al., 1998;).

Men are more likely than women to be overweight, but women are more likely to be obese, especially with BMIs greater than 35 (Hedley, et al., 2004). Differences in overweight and obesity rates for women vary starkly by race and ethnicity but are not as apparent for men (Flegal, et al., 1998; Hedley, et al., 2004). According to the National Center for Health Statistics analysis of NHANES data (Hedley, et al., 2004), 77.5 percent of Black women are overweight, compared to 71.4 percent of Mexican women and 57 percent of White women. The prevalence of obesity is similarly skewed with the rates for Black, Mexican and White women at 49.6 percent, 38.9 percent and 31.3 percent, respectively. In fact, over 10 percent of middle-aged Black women have BMIs greater than 40 (Flegal, et al., 1998).

1.10 Relationship of Body Size to Mortality and Disease

It is well established that overweight and obesity are significantly related to higher rates of several chronic health conditions including diabetes, hypertension, high cholesterol, coronary heart disease, arthritis, and certain types of cancer (Mokdad, et al., 2003; Flegal, et al., 2007). The relationship between obesity and mortality has been less definitive, but recent research has documented a stronger association than years past.

1.11 Relationship of Body Size to Functional Status

The shape comparison of average women obtained from 3 different surveys gives an indication of the profound changes that have occurred in anthropometry over the last half-century. The average UK woman has increased substantially in weight and body girths since 1951 (Kemsley, 1957), gaining 16 cm in WC despite being only 4 cm taller. The average contemporary US woman has even greater waist and weight than her UK counterpart, despite being 3 cm shorter. As is well recognized, the US population began the trend toward obesity earlier than did European populations, and, without progress in obesity prevention, the UK population is likely to continue to expand in weight and girths.

In cross-sectional analyses, obese individuals tend to have an increased prevalence of both upper and lower body functional limitations (Apovian, et al., 2002), and the relationship between obesity and limitations appears to be slightly higher for elderly women than elderly men (Davison, et al., 2002). Longitudinal studies find that these relationships hold for the onset of limitations as well (Ferraro, et al., 2002; Himes, 2000; Jenkins, 2004). Excess weight adds stress to the skeleton and weight-bearing joints, increasing the likelihood of arthritis and joint problems. Physiologically, excess weight leads to increased insulin resistance, damages connective tissues and leads to atherogenesis. It is hypothesized that these changes can lead to decreased functioning (Ferraro & Booth, 1999).

Obesity may also limit physical activity, depriving individuals of the benefits of exercise and leading to the development of limitations in activities of daily living (ADLs) and instrumental activities of daily living (IADLs) such as climbing stairs, getting out of bed, or going shopping.

1.12 Aim and Objectives

Aim and objectives are to study the physiological effects of obesity and 3D body scanning.

• To study UCL population in conjunction with Wellbeing UCL survey
• To examine available data from UCL Wellbeing survey
• To statistically analyse data obtained
• To evaluate the data
• To make deductions from these data about the effect of obesity on the physiological parameters have looked at.
• To conclude with implication of my findings