What is Obesity?

Clinically, obesity is described as the excessive accumulation of fat that exceeds the body's skeletal and physical standards. The National Institute of Health (NIH) states that excessive weight becomes a health hazard when it is 20 percent or more above ideal body weight.

Obesity becomes a serious health risk when it becomes morbid. In such cases the patient is susceptible to serious diseases like chronic heart disease, respiratory diseases or even infertility. Called co-morbidities, these conditions or diseases may result in either significant physical disability or even death. Morbid Obesity is described as having a Body Mass Index of 40 or higher. According to the National Institutes of Health Consensus Report, morbid obesity is a serious disease and must be treated as such. It is a chronic disease, meaning that morbid obesity symptoms build slowly over an extended period of time.

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Causes of Obesity?

Research shows that the recent rise in obesity is due to changed lifestyles, energy-dense diets and low-levels of physical activity. However various factors may contribute to obesity which include environmental factors, heredity, psychological & cultural influences and many others. Various possible causes of obesity, as suggested by renowned doctors, are given below:

Heredity

Research shows that heredity influences fatness and the distribution of fat tissue. Heavy newborns grow into heavy adolescents only when either parent is overweight or obese. Weight regulation in the human body depends upon various hormonal and neural factors which are genetically determined. Any abnormality in these factors could result in substantial weight gain. Size and number of fat cells, distribution of body fat, and RMR are also determined genetically. In 66% to 80% of the cases, obesity is found to be inherited. Studies have proved that above 250 genes, markers and chromosomes are linked obesity. Genetic conditions like the Prader-Willi syndrome may also lead to obesity and linked diseases.

However, there is no complete consensus on the fact that an abnormality in genes may lead to obesity. A recent study shows that while genes may increase vulnerability to obesity, the presence of other factors, like the environment, is necessary for obesity to actually occur.

Metabolic Factors

Before we study the metabolic factors that lead to obesity we need to have a basic understanding of metabolism in the human body. In short, basal metabolism rate (BMR) is the energy (measured in calories) used by the body at rest to maintain normal bodily functions. This continuous activity contributes to 60-70% of the amount of calories we “burn’ in a day. Increased activity increases the BMR and the amount of calories burnt. Most obese people lead an inactive life, thus their energy expenditure is minimal. Low levels of spontaneous physical activity leads to vulnerability towards obesity.

Modern lifestyles have also done their share to contribute towards obesity. Endless hours of working, sitting at the computer and leisure activities like watching television have reduced energy expenditure on physical activity. This combined with eating more calories than needed, have led to the growing problem of obesity.

Endocrinological Causes

Sometimes obesity may be a result of a hormonal imbalance or glandular problem. However this is a rare occurrence and contributes to less than 1% of all weight gain in the world. Diseases like Cushing Syndrome cause substantial weight gain, most of which is oriented centrally. This kind of obesity may lead to hypertension and diabetes. In addition some hypothalamic lesions like tumors, infections or severe trauma could also lead to obesity. Hypothyroidism may also cause weight gain by reducing the metabolic rate. Hypogonadism in men and Polycystic Ovarian Syndrome in women may be associated with mild obesity although the reasons for weight gain in such cases are yet unclear.

Medication

Certain drugs may contribute to weight gain, such as corticosteroids, sulfonylureas for diabetes, steroidal contraceptives and anticonvulsants such as valproate used in epileptic therapy. Antipsychotics, antidepressants, mood stabilizers like lithium are medicines that have weight gain as a side effect.

Psychological Causes

Several research models show that obesity is linked to various behavioral and emotional processes that may originate due to genetic or environmental reasons. Though these factors play a minor role in the development of obesity, they are important in relation to responses to treatment. For example, many patients reduce depressive symptoms by eating. These people may gain weight with one episode of depression and increase it with the next. Further, concepts of dietary restraints, body image dissatisfaction and binge eating disorders have been intimately linked to the increase in obesity today.

Dietary Factors

Various studies conducted attribute an increase in caloric intake as the major cause of the current obesity epidemic. Changes in lifestyle, food systems, and increased portion sizes have been cited as causes for increased caloric intake. Larger portion sizes have led to a 30% increase in overeating. Eating out frequently also leads to increased calorie intakes as one meal served in restaurants and fast food outlets exceeds a person’s caloric needs for the entire day.

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Health Risks?

Mortality
Research shows that excessive body weight is linked to overall health and susceptibility to chronic ailments. It has been proven that a BMI beyond 20 kg/m2, increases the risk of cardiovascular death, heart attack and diabetes, even after adjusting for age, smoking, social class, alcohol consumption and physical activity. Studies show that non smoking overweight men and women lose 3.1 and 3.3 years of life respectively compared to normal weight non smokers. These studies have also established that weight fluctuations increase the risk of death.

Coronary heart disease is the major cause of weight-related death followed by diabetes mellitus, digestive diseases and cancer. Evidence suggests that women can reduce mortality rate by 25% in diabetic, cardiovascular and cancer conditions by achieving a weight loss of 9 kgs. However if an obese person has already developed an associated co-morbidity, then planned weight loss of any amount has been reported to reduce mortality by 20%. It has also been established the risk of mortality is greater in younger patients suffering from obesity as compared to older ones.

Morbidity
Obesity is associated with chronic diseases such as heart disease, Type 2 diabetes, hypertension, stroke, gallbladder disease, sleep apnea, certain cancers and osteoarthritis. These chronic ailments tend to worsen with increasing degree of obesity. Nonalcoholic fatty liver disease which may progress to end-stage liver disease is now also being recognized as a consequence of obesity. Obesity may also lead to poor wound healing and poor antibody response to hepatitis B vaccine.

Regional Distribution of fat and Health Risk
There are basically two types of obesity; Android or apple-shape obesity where the excess fat is primarily subcutaneous abdominal/truncal fat or gynoid or pear-shape obesity where excess fat is gluteofemoral fat. This fat distribution is determined genetically and varies among men and women. Android obesity is more common among males whereas females are more susceptible to gynoid obesity. While incase of gynoid obesity it is more difficult to shed weight, the android obesity is linked to chronic ailments such as glucose intolerance, insulin resistance, hyperlipidemia and hypertension. Aging is also an important factor in the development of central obesity. This type of obesity is also closely associated with the development of metabolic syndrome (a complex of unified conditions like glucose intolerance, high blood pressure and alterations in serum lipids).

Psychological Effects
Obesity and dieting are strongly related to an individual’s psyche. Studies show that many obese people suffer from low self esteem which frequently manifests itself as anxiety and depression. A study done on severely obese subjects showed poor mental well-being. Most of them were also found to be suffering from anxiety and depression. A further study done on siblings, one being severely obese and other normal weight, showed that functional and emotional wellbeing was significantly lower in severely obese siblings.

Effect of obesity on pregnancy
The risk of obstetric complication is higher in obese women. Significantly obese women with an IBW of > 135% have a 6.6-fold higher risk for the development of gestational diabetes, 1.9-fold risk for pregnancy-induced hypertension, 1.4-fold risk for urinary tract infections as well as other complications like pre-eclampsia, thrombophlebitis, post-partum haemorrhage and wound or episiotomy infections. Factors such as fetal size, especially macrosomia, an increase in maternal pelvic soft tissue narrowing the birth canal, late deceleration of the fetal heart rate, intrapartum meconium staining, prolonged labor, malpresentations and cord incidents raise the risk of caesarean delivery. This higher prevalence of a Caesarean delivery occurs with or without antenatal complications. Fetal weight appears to be a direct function of maternal size, with more than 50% of obese women having babies who weigh greater than 3600g. An increased risk of neural tube defects, especially spina bifida has also been reported in women with BMI greater than 29. Further, the protective effects of dietary folic acid as seen in leaner women are not seen in women weighing over 70 kg. Studies have also shown that prenatal deaths were 3 times more common in obese women than their counterparts.

Obesity and incidence of maternal complications during pregnancy as summarized as follows –

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Assessing the Risk Factors

Ideal Weight Table

Find out your approximate ideal weight using the following table.

Adapted from The Metropolitan Life Insurance Table. Covers a wide range of ideal weight according to height.

Note : Refer to a specialist for precise calculation

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BMI

Grade 1 to Grade 3
Obesity is applicable to all age groups
(Source : World Health Organisations)

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WAIST

NORMAL
WAIST / HIP RATIO
< 1.0 in Males < 0.8 in Females

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Benefits of weight loss?

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