Obesity is due to the positive energy balance, the intake of calories is more than the expenditure of calories. It is a state in which there is generalised accumulation of excess adipose tissue in the body leading to more than our desirable weight.
One in every two adults in the United States is overweight and the prevalence of obesity is increasing all over the world.
Genetic Inheritence probably influences 50-70 per cent a person’s chance of becoming fat more than any other factors. Within families, the chance is 80 per cent if both parents are obese and 50 per cent if one parent is obese.
A mutation in the human gene for the B3 recepters in adipose tissue, involved in lipolysis and thermogenesis markedly increase the risk of obesity. Many genes play a role in food intake regulation, apetite and ultimately obesity in mammals.
AGE AND SEX
It can occur at any age in either sex as long as the person is under positive energy balance. Females than males are found to be over weight among all age groups. Hormonal predisposition put women at higher risk of obesity when compared to men.
Certain types of eating habits may lead to obesity:
- nibbling between meals is a potential cause of obesity.
- Some may eat faster taking less time for chewing, therefore they tend to consume more food.
- People who eat outside home more frequently are prone to obesity. large portion of food served outside the home promote high calorie consumption.
- People who eat more junk food (high fat, high carbohydrate) may become obese.
- Non inclusion of fruits and vegetables.
- Non-vegetarian diet favour weight gain.
- Consumption of sugar added beverages may contribute to weight gain.
- Personnel who work in different shifts, whose body clock is disturbed, may have chance of getting obese.
NO PHYSICAL ACTIVITY
Obesity is found in persons who lead to sedentary lives and pay less importance to physical activity. It is more common in middle age when physical activity decreases without corresponding decreasing in food consumption.
Food is one of the many stimulants of endorphin, ‘feel good’ neurotransmitter. Self gratification, depression, anxiety and stress may lead to excess calorie intake. Recent studies have shown that school going children tend to take more fatty foods as their lives grow stressful. Chronic sleep deprivation may increase appetite in some.
Obesity may follow due to damage of hypothalamus after head injury because it is not able to regulate appetite or satiety.
Obesity is found in hypothyroidism, hypogonodism and cushing’s syndrome. Obesity is common at puberty, pregnancy and menopause.
PROSPERITY AND CIVILISATION
Obesity is common in prosperous countries like UK, USSR, and USA and among people from higher socioeconomic status of developing countries, since they have the purchasing power and availability of surplus food. Obesity is rare in primitive societies and wild animals. Civilisation has brought plentiful supply of appetising foods, concentrated foods and variety of foods in the market.