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.

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:


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.


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.