Causes and Mechanisms

The causes of obesity are multiple and include factors such as genetic inheritance, the behavior of the nervous system, endocrine and metabolic, and the type or style of life that takes.

* Increased intake of calories the body needs.
* Decreased physical activity in which the body needs.

Genetics

As with many medical conditions, the caloric imbalance that results in obesity often develops from a combination of genetic and environmental factors. Polymorphism in various genes controlling appetite, metabolism and the integration of adipoquina, predispose to obesity, but the condition requires the availability of sufficient calories, and possibly other factors to fully develop.

If ingested more energy than necessary it accumulates as fat. If you consume more energy than necessary it is stored as fat for energy. As obesity is caused by excess energy as a result of alterations in the balance of input / output energy. As a result various complications can occur, such as hypertension, diabetes mellitus and coronary heart disease.

Heredity plays an important role, as parents are obese your risk of obesity for a child is 10 times higher than normal. Is partly due to trends of metabolic fat accumulation, but it is partly due to cultural food habits and sedentary contributes to repeat patterns from parent to child obesity.

Another part of the obese are hormone or endocrine diseases, and can be solved by a correct diagnosis and specialized treatment.

Lifestyle

Most researchers have concluded that the combination of excessive nutrients and sedentary lifestyle are the main cause of the rapid acceleration of obesity in western society in the last quarter of the twentieth century.

Despite the widespread availability of nutritional information in schools, clinics, grocery stores and the Internet, it is clear that the excess consumption remains a problem. For example, reliance on fast food dense in energy, has tripled between 1977 and 1995, and calorie consumption has quadrupled over the same period.

However, consumption of food by itself is insufficient to explain the phenomenal increase in the levels of obesity in the industrialized world in recent years. An increase in sedentary lifestyle also has a significant role to play. More and more research into childhood obesity, for example, I read things such as running at school, with high levels of this disease.

Questions about lifestyle, less well established, which may influence obesity include mental stress and sleeping enough

Several genetic conditions that are characteristic of obesity, have been identified (such as Prader-Willi syndrome, the Bardet-Biedl syndrome, MOMO syndrome, mutations in the leptin receptor and melanocortina), but mutations in single locus only have been found in 5% of obese individuals. While it is believed that a large proportion of the causative genes are still unidentified, for which obesity is most likely a result of interactions between multiple genes, where non-genetic factors are probably also important.

A 2007 study identified several common mutations in the FTO gene, the heterozygote had a risk of obesity increased 30%, whereas homozygotes had an increased risk of 70% .

A population level, the hypothesis of gene saver, which postulates that certain ethnic groups may be more prone to obesity than others and the ability to take advantage of rare periods of abundance and and use this abundance for storing energy efficiently may have an advantage evolutionary, in times when food was scarce. Individuals with greater adipose reserves were more likely to survive famine. This tendency to store fat is probably inappropriate in a society with a stable supply of food.

Medical illnesses

Certain physical and mental illness and in particular pharmaceutical substances may predispose to obesity.

Apart from the fact that correcting these situations can improve obesity, the presence of an increase in body weight can complicate the management of others.

Medical illnesses that increase the risk of obesity include several rare congenital syndromes, hypothyroidism, Cushing syndrome, a deficiency of growth hormone.

Quitting smoking is a known cause moderate weight gain, because nicotine suppresses appetite. Certain medical treatments (steroids, atypical antipsychotics, some fertility drugs) can cause weight gain.

Mental illness may also increase the risk of obesity, especially some eating disorders such as bulimia nervosa and compulsive consumption (also known as food addiction).