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Causes of obesity

Problem 1: Diagnosing Causes For Sudden Rise in Obesity Levels

Any explanation of the root causes of the current obesity epidemic must account for its sudden appearance. Six million American adults are now morbidly obese (BMI 40+), almost twice as high as 1980 severe obesity rates, while another 9.6 million have a BMI of 35-40. The percentage of overweight children 6-11 has nearly doubled since the early 1980's. (Source: US Census 2000; NHANES III data estimates). Thus genetic causes are unlikely to be significant. Because while a predisposition to obesity can be inherited, the fact that obesity has increased so much in the last few decades appears to discount genetics as a major main cause. Also, the fact that each succeeding generation is heavier than the last indicates that changes in our environment are playing the key role.

Problem 2: Separating Genetic Causes From Environmental Causes

Obesity tends to run in families, suggesting a genetic link. Yet families also share common dietary, physical exercise, attitude and lifestyle habits that may also contribute to obesity. Separating these from purely genetic factors is not an easy statistical or diagnostic task.

Environmental Causes of Obesity

In view of the sudden rise in weight levels - which is a worldwide trend as reflected in the new word "globesity" - environmental factors must be the prime cause of modern obesity.

Overconsumption - A Possible Root Cause

Eating too many calories for our enery needs must be a major candidate for the main cause of the modern obesity epidemic. According to Dr. Marion Nestle, Professor and Chair of the Department of Nutrition and Food Studies at New York University, US agribusiness now produces 3,800 calories of food a day for every American, 500 calories more than 30 years ago — but at much lower per-calorie costs. Increases in consumption of calorie-dense foods, as evidenced by the growth of fast-food chains and higher soft drink consumption, also point to a higher energy-intake.
NOTE: For an explanation of how surplus calories - from dietary fat, protein or carbohydrate - are stored as body fat, please see: Body Fat/Adipose Tissue - Why We Gain Fat

Eating Too Many High-Fat or Refined Sugary Foods

The type of food eaten may also play an important role in the rise of obesity. Researchers continue to discover more metabolic and digestive disorders resulting from overconsumption of trans-fats and refined white flour carbohydrates, combined with low fiber intake. These eating patterns are known to interfere with food and energy metabolism in the body, and cause excessive fat storage. Associated health disorders include insulin resistance, type 2 diabetes as well as obesity. Incidence of these "modern" diseases is increasing worldwide.

Reduced Energy Expenditure - A Possible Root Cause

People who eat more calories need to burn more calories, otherwise their calorie surplus is stored as fat. For example, if we eat 100 more food calories a day than we burn, we gain about 1 pound in a month. That’s about 10 pounds in a year. Over two decades this energy surplus causes a weight gain of 200 pounds!
Assessing the contribution of lack of exercise to obesity is hampered by lack of research. According to existing surveys, only 20 percent of the population are frequent exercisers. In addition, only a small minority of children (1 in 5) regularly participate in after-school sports or extra-curricular physical activity. Since 1990, among adults there has been a per capita decline of 15 percent in frequent exercise activity (100+ days per year in any one activity). Among teenagers and adolescents aged 12-17, the plunge is 41 percent.
However, data on correlation between BMI and exercise frequency is almost non-existent, so we are unable to say exactly what effect lack of exercise has on obesity. What we do know is that severe clinical obesity leads to serious mobility problems caused by respiratory and musculoskeletal disorders. Thus the fitness capacity of obese individuals, especially those suffering from morbid obesity, is typically diminished.

Family Influence - A Major Contributory Cause to Obesity

Parental behavioral patterns concerning shopping, cooking, eating and exercise, have an important influence on a child's energy balance and ultimately their weight. Thus family diet and lifestyle are important contributory causes to modern child obesity, especially at a time of rising affluence. Since obese children and adolescents frequently grow up to become obese adults, it's clear that family influence also extends to adult obesity.

Genetic Causes of Modern Obesity

Genes affect a number of weight-related processes in the body, such as metabolic rate, blood glucose metabolism, fat-storage, hormones, to name but a few. Also, some studies of adopted children indicate that adopted children tend to develop weight problems similar to their biological, rather than adoptive, parents. In addition, infants born to overweight mothers have been found to be less active and to gain more weight by the age of three months when compared with infants of normal weight mothers, suggesting a possible inborn drive to conserve energy. Research has also shown that normal-weight children of obese parents may have a lower metabolic rate than normal-weight children of non-obese parents, which can lead to weight problems in adulthood. All of this suggests that a predisposition to obesity can be inherited.
However, the fact that obesity has increased so much in the last few decades appears to discount genetics as the main cause. According to Stephen O'Rahilly, professor of clinical biochemistry and medicine at Cambridge University, the influence of genetics on modern levels of obesity is insignificant:
"Nothing genetic explains the rise in obesity. We can't change our genes over 30 years."




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CAUSES FOR OBESITY (I)
 The causes for OBESITY to date have not been totally understood. However, it is a known fact that there are endless factors which cause this serious disease, some which appear to be very simple and others very complicated.
 To mention the most important causes, there are the following:
GENETICS
METABOLICS
PSYCHOLOGICAL
SOCIOCULTURAL
SEDENTARY LIFESTYLE
NEUROENDOCRINES
MEDICAMENTAL
HIGH CALORIC NUTRITION
MULTIPLE FACTORS
METABOLIC
 Some people handle the use of calories better in order to keep up the body temperature and to carry out the metabolic processes.
PSYCHOLOGICAL
 Recent discoveries have transformed the theory that psychological causes can increase obesity and now consider the psychological changes in obesity as the consequence, not as the cause.
SOCIOCULTURAL
 Indubitably all our surroundings greatly influence obesity. All social environment gathers around food and drink.
 Food itself has become a "prize" to the behavior.
 Food has become the "ideal closure" to a successful business transaction.
 All religions have a background of the type of food that should be consumed (fasting, kosher, liquids with a full moon, etc).
 And so could we continue with several examples.
SEDENTARY LIFESTYLE
 Sedentary lifestyle is one of the principal causes for obesity.
 And it has been proven that physical activity is one of the greatest factors of the use of body energy.
 The increase in physical activity allows the intake of more calories and achieves a more favorable caloric balance of the body to avoid obesity.
NEUROENDOCRINES
Obesity originating in the hypothalamus.
Cushing Illness (high levels of cortisol).
Hypothyroidism (low levels of thyroids).
Policystic ovary syndrome.
Growth hormone deficiency.
MEDICAMENTAL
 Tricyclic anti depressives have shown an increase in fat and an important weight gain, thus presenting an obesity condition.
 Long corticoid treatments have shown an increase in fat and in weight also presenting obesity.
HIGH CALORIC NUTRITION
 Intake of more calories than our bodies require definitely cause the caloric balance to accumulate and for every 7,500 calories that our body accumulates the weight gain is 1 KG which leads to obesity.
MULTIPLE FACTORS
 It has been proven that in the majority of obesity cases we will find an origin of many factors which lead us to a more complicated treatment than one would believe.



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