Etiological Factor Contributing to Obesity
1. Genetic Factor:
Genetic inheritances probably influence 50-70% a person chances of becoming fat more than any other factor. A genetic base regulates species difference in body fat and sexual differences within a species, within families the chances are 80% if both parents are obese and 50 % if one parent is obese. A mutation in the human gene for the B3 receptor in adipose tissue, involved in lipolysis and thermogenesis markedly increase the risk of obesity.
Many genes play a role in energy homeostasis, food intake regulation, appetite and ultimately obesity in mammals.
2. Role of Ghrelin and Leptin on Obesity:
Tschop M et al, (2002) in Nature, fasting stimulates Ghrelin secretion from their neurons and there Ghrelin stimulates the hypothalamic Satiety center, There NPY/AGRP neuron has stimulated that increase the food intake causing obesity.
Otherwise, Leptin inhibits the NPY/AGRP neuron decreasing the food intake.
3. Basic Energy balance:
Some person suffers from congenital obesity, a major cause of obesity in sedentary man is lack of obesity. The overall underlying energy imbalance is the ultimate causes for excess weight. Excess intake is stored in the body as fat. About 3500 kcal is equivalent to 1 lb of body fat. A minor daily imbalance where energy intake excesses output by a mere 5% can result in a weight gain of 5 kg in a year.
4. Physiological Factor:
The amount of body fat of a person carries weather through inheritance or eating habits is related to the number and size of fat cell in the body. Critical periods for developing obesity occur during early growth periods when cells are multiplying rapidly in childhood and adolescent.
Middle age and older adults may store more fat because of a decrease in basal metabolic rate, physical activity, and muscle mass. Women store fat during pregnancy and after menopause in response to hormonal changes.
5. Environmental Factor
A. Sedentary Behavior:
- Physical inactivity is a major element in the development of obesity in westernized societies in children and adults alike.
- International studies have shown that television viewing is associated with an increased incidence of a new case of obesity.
- There are as yet no clear data linking viewing of interact videos or using computer or other electronic media with the development of obesity, although they are likely to be associated.
B. Eating Habits:
- Nibbling between meals is common among housewife and it is a potential cause of obesity.
- Some may eat faster taking less time for chewing, therefore they tend to consume more food.
- Housewives who do not leftover food to be thrown out may consume and put an weight.
- People who eat outside have more frequently are prone to obesity
- People who eat more junk food may become obese
- Some may eat more food when they are unhappy as a compensation mechanism.
Data from the United States show that there is an increased risk of obesity in Native Americans, and Hispanic American compared with White Americans, although these differences may be largely related to the difference in Socio-economic status.
7. Age and Sex:
It can occur at any age in either sex as long as the person in under positive energy balances. Studies conducted at nutrition foundation of Indian have shown more females than males are found to be overweight in all age group.
8. Abnormalities of glandular function or metabolism:
A minor group of people suffers from obesity due to malfunctioning of some one or more of the endocrine glands I.e.-thyroid, pituitary, or sex gland.
9. Social Factor:
People in the upper socioeconomic status tend to be more obese mainly due to their rich food intake and lifestyle which involves minimum physical activity.
10.Underlying Medical Disorder:
Sedentary obesity may occur with the medical condition, including hypothyroidism, growth hormone deficiency and hypothalamic damage.
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