Causes for Overweight and Obesity

Causes for Overweight and Obesity

Also known as adiposity, overweight and obesity are increasingly common conditions in the United States. They are caused by the increase in the size and the amount of fat cells in the body. Doctors measure body mass index (BMI) and waist circumference to screen and diagnose overweight and obesity. Obesity is a serious medical condition that can cause complications such as metabolic syndrome, high blood pressure, atherosclerosis, heart disease, diabetes, high blood cholesterol, cancers and sleep disorders. Treatment depends on the cause and severity of your condition and whether you have complications. Treatments include lifestyle changes, such as heart-healthy eating and increased physical activity, and Food and Drug Administration (FDA)-approved weight-loss medicines. For some people, surgery may be a treatment option.

Causes for Overweight and Obesity
Energy imbalances, some genetic or endocrine medical conditions, and certain medicines are known to cause overweight or obesity.

1. Energy imbalances cause the body to store fat
Energy imbalances can cause overweight and obesity. An energy imbalance means that your energy IN does not equal your energy OUT. This energy is measured in calories. Energy IN is the amount of calories you get from food and drinks. Energy OUT is the amount of calories that your body uses for things such as breathing, digesting, being physically active, and regulating body temperature.

• make energy for immediate use to power routine daily body functions and physical activity.

• store energy for future use by your body. Sugars are stored asglycogen in the liver and muscles. Fats are stored mainly as triglyceride in fat tissue.

The body has three types of fat tissue—white, brown, and beige—that it uses to fuel itself, regulate its temperature in response to cold, and store energy for future use. Learn about the role of each fat type in maintaining energy balance in the body.

• White fat tissue can be found around the kidneys and under the skin in the buttocks, thighs, and abdomen. This fat type stores energy, makes hormone that control the way the body regulates urges to eat or stop eating, and makesinflammatory substances that can lead to complications.

• Brown fat tissue is located in the upper back area of human infants. This fat type releases stored energy as heat energy when a baby is cold. It also can make inflammatory substances. Brown fat can be seen in children and adults.

• Beige fat tissue is seen in the neck, shoulders, back, chest and abdomen of adults and resembles brown fat tissue. This fat type, which uses carbohydrates and fats to produce heat, increases when children and adults are exposed to cold.

2. Medical conditions
Some genetic syndromes and endocrine disorders can cause overweight or obesity.
                 
2.1. Genetic syndromes
Several genetic syndromes are associated with overweight and obesity, including the following.

• Prader-Willi syndrome

• Bardet-Biedl syndrome

• Alström syndrome

• Cohen syndrome

2.2 Endocrine disorders
Because the endocrine system produces hormones that help maintain energy balances in the body, the following endocrine disorders or tumor affecting the endocrine system can cause overweight and obesity.

• Hypothyroidism. People with this condition have low levels of thyroid hormones. These low levels are associated with decreased metabolism and weight gain, even when food intake is reduced. People with hypothyroidism also produce less body heat, have a lower body temperature, and do not efficiently use stored fat for energy.

• Cushing’s syndrome. People with this condition have high levels of glucocorticoids, such ascortisol, in the blood. High cortisol levels make the body feel like it is underchronic stress. As a result, people have an increase in appetite and the body will store more fat. Cushing’s syndrome may develop after taking certain medicines or because the body naturally makes too much cortisol.

• Tumors. Some tumors, such as craneopharingioma, can cause severe obesity because the tumors develop near parts of the brain that control hunger.

*Source: https://www.nhlbi.nih.gov/health-topics/overweight-and-obesity