Obesity

Obesity

Obesity is the excess of body fat. The human body is made up of water, fat, protein, carbohydrates, minerals, and vitamins. People having extra body fat around their waist area are more prone to diseases. They may suffer from high blood pressure, high levels of blood cholesterol, diabetes, heart disease, and stroke. Obesity is a risk factor in heart disease which may lead to the cause of heart attacks.

Causes of Obesity

·         Unbalanced diet: Obesity occurs when your calorie intake is more than your calorie expenditure.  A reasonably active man in India needs to consume 2,800 K calories per day approximately while a woman needs to consume approximately 2,200 K calories per day.  Your diet should have balanced amounts of carbohydrates, proteins, fats, fibres, minerals, and vitamins.  Taking high quantities of calories in the form of saturated fats can lead to obesity. 

·         Fat cells: Surplus calories are stored as triglycerides in fat cells. There is more number of fat cells in obese people. These fat cells in obese people are larger too.  Overeating, further aids in the growth of these fat cells. There are specific periods when fat cells accumulate in the body and it is easier to gain weight.  This usually occurs between ages 12-18 months, 12-16 years, and after adulthood when a person can gain more than 60 per cent of his/her ideal body weight.  Overfeeding in early years can increase the number and size of fat cells. However, in the case of adult onset obesity, the number of the cells does not change but the size increases. Fat gained during these strategic periods, is usually hard to shed.

     

·         Age: If your level of activity and intake of calories remain constant, as you age, you will still gain weight. This happens because the rate of metabolism slows down when you grow older.  You do not need to consume the same number of calories to keep up your weight.

·         Gender: Men need to consume more calories as compared to women, to maintain their body weight, as they have a higher resting metabolic rate (RMR) than women do. 

·         Level of Activity: Less active people require fewer calories than more active people do.  In the obese, activity decreases the craving for food and hastens the metabolism process of fat as a source of energy.

·         Body Weight: Heavier persons need to consume more calories to keep up their body weight.  If they reduce the intake of calories, their rate of metabolism will slow down and when coupled with a moderately active lifestyle, they will lose weight.  At this stage, they would need to consume only the reduced number of calories to maintain their weight.

·         Seasonal Fluctuation: During winters, more fat is stored in adipose tissues to serve as an insulator.  This additional weight is shed in the summers, as the level of activity increases and the amount of consumption of food decreases. These changes are brought about, partially, because of the lengthening of the day and the presence of additional light.

·         Genetic factors: The child’s weight is always linked to the weight of the biological mother. Depending on whether the mother is heavy or thin, there is a 75 per cent chance that her children will grow up to be obese or thin.  This is not related to hyperthyroidism, which is not such a common cause for obesity, as is generally believed.  It is also thought that the mitochondria in obese and normal-weight individuals might vary.  The mitochondria are the powerhouses of the cell. They are responsible for the production of energy.  Mitochondria are inherited only from the mother, thus accounting for the positive correlation of a child’s weight with that of the biological mother.

·         Fat cells secrete a hormone called leptin, which is affected by your genes.  It determines how well the fat is oxidized.  When the amount of fat in the body is high, leptin cannot function efficiently, thus enabling a person to gain weight.  On the other hand, it is observed that when the level of leptin is very low, it might lead to anorexia.

·         It is widely believed that obesity results from the occurrence of a gene, which creates an aberrant protein in the blood that gets in the way of feeling satiated even after a meal. In August 1995, an aberration was discovered in the gene that is accountable for Beta-3 adrenergic receptor, which is found mostly in the tissues of fat in the abdomen.  This aberration leads to a drop in the generating heat because the fat tissues in the cells cannot be burned up to produce heat.  People suffering from this will have a lower RMR leading to faster weight gain.

·         Environment: Besides genetics, environment also has an impact on the child.  Food habits, activities, and attitudes towards the health and the body are largely learnt at home.  If the parents are obese, lead a sedentary lifestyle, and consume a high fat diet, chances are that the child too, would grow up obese.

·         Other Hypotheses: One line of thought claims that the cause of obesity is the brown fat cells, which are usually found in the shoulders and the kidneys.  Though, these cells comprise only a tiny percentage of the total body fat, they are responsible for producing heat.  It is known that brown fat keeps the hibernating animals warm.  In human beings, it prevents calories from being converted into fat by burning them for energy and heat.  It is thought that in obese individuals this fat is deficient.

·         An enzyme called lipoprotein lipase (LPL) is found in fatty tissues.  LPL uses fat present in the blood and converts it into energy.  Some believe that this enzyme might be responsible for losing weight and maintaining weight loss.