Causes of Obesity
Causes of obesity, briefly described below are several contributing causes on obesity.
Diet
A high-fat diet can certainly contribute to an increased risk for obesity. In fact, the body notoriously becomes more efficient at meeting challenges. The body may, in a high-fat diet, learn to store fat more easily–which would increase one’s body fat percentage.
Genetics
It is well established through “twin studies” research that genetics plays a role in obesity. Identical twins, who have the same genetic makeup, are more likely to be obese than are fraternal twins. Currently, there is much research investigating pharmaceuticals and the link between genetics and obesity…which means there is also concomitant increase in the number of scams associated with “quick fix” weight loss programs.
Metabolic Rate
Metabolism refers to the sum of all chemical reactions occurring in the body. On a more general level, one can think of the balance between the energy we put into our bodies through food versus the energy we give off through sleep, rest, temperature change, digestion, exercise and other activities. A person who expends a lot of energy is said to have a “high metabolic rate” (keep in mind this is a very simplified application to a complex concept). Metabolism is higher during periods of growth, pregnancy and physical activity. An individual with a ‘high metabolic rate’ is less likely to be obese than a person with a “low metabolic rate.”
Lipoprotein Lipase Activity
Lipoprotein lipase is an enzyme that can trigger triglycerides (the fat most commonly consumed in a typical diet) to release fatty acids into muscle or fat cells, causing fat deposition i.e. the cells become fatter. Therefore, an individual with elevated lipoprotein lipase activity is more likely to be obese than an individual with lower lipoprotein lipase activity.
Hormonal Disorders
Metabolic, or hormonal, disorders that can be causes of obesity include autoimmune thyroid disease, polycystic ovarian syndrome, and Cushing’s syndrome.
Autoimmune Thyroid Disease
The thyroid is a butterfly-shaped gland located in the front of the neck. The thyroid, involved with many body functions including metabolism, releases several hormones, two of which are known as “T4″ and “T3.” T4 and T3 (T3 being the ‘active’ form of T4) function to help the body convert oxygen and calories from food into energy. The release of these hormones occurs from a feedback mechanism. A hormone, TRH, is released from the brain’s hypothalamus. The release of TRH (thyrotropin releasing hormone), in turn, causes the release of TSH (thyroid stimulating hormone) from the pituitary gland. The amount of TSH circulating in the blood tells the thyroid how much T3 and T4 to release.
In autoimmune thyroid disease, antibodies attack the thyroid, causing damage to the gland. The damage usually results in a reduction of thyroid hormone released, or hypothyroidism. The brain tries to increase the amount of thyroid hormone by releasing more TSH, but the damaged thyroid is unable to respond. A person whose blood tests show low levels of T4 and T3 and high levels of TSH may be considered “hypothyroid.” This hypothyroidism condition, the result of antibodies attacking the thyroid gland, is termed Hashimoto’s Thyroiditis, or Hashimoto’s Disease. Symptoms of Hashimoto’s Disease are many and can include weight gain, changes in blood pressure, heart palpitations, anxiety, changes in mood, hair loss, lack of energy, exhaustion, sensitivity to heat or cold, muscle and joint pain, puffiness in the eyes or other facial features, low sex drive, and concentration problems. A person with Hashimoto’s Disease may put on weight because of the low thyroid hormone levels in the body. The weight gain can be worsened by other symptoms, such as mood changes and the lack of energy. Individuals diagnosed with Hashimoto’s Disease are typically put on thyroid hormone replacement therapy.
Interestingly, however, diagnosis may not occur for many. Blood tests issues usually involve obtaining T4, T3 and TSH, but a person can have normal levels of these hormones and still have autoimmune thyroid disease. Therefore, a blood test for thyroid antibodies can better diagnose a patient suffering from the above symptoms. Once diagnosed, the Hashimoto’s patient usually is prescribed thyroid hormone therapy. Symptoms may be alleviate for some, less so for others.
Grave’s Disease is another autoimmune thyroid disease also caused by antibodies. The antibodies serve to increase the release of T4 and T3, causing another laundry list of symptoms, including unexplained weight loss, bulging of the eyes, hand tremor, restless leg syndrome, mental confusion, inability to sleep, dry skin, erratic behavior, sensitivity to heat or cold, high blood pressure, insomnia or difficulty remaining asleep, and muscle weakness in the upper arms and legs. Interestingly, the medical community currently treats Grave’s Disease by reducing the activity of the thyroid via radioactive iodine treatment (RAI). RAI partially or fully disables the thyroid, so the body becomes hypothyroid. The patient then is prescribed thyroid hormone therapy. Some endocrinologists first try to treat the condition using antithyroid medications, hoping the Grave’s Disease will go into remission. In severe cases, the entire thyroid is removed, rendering the patient hypothyroid.
Polycystic Ovarian Syndrome
In Polycystic Ovarian Syndrome, there is an excess of androgen (”male”) hormones, and an imbalance of other hormones e.g. Follicle Stimulating Hormone, secreted by the pituitary gland.
The hormonal imbalance may lead to irregular or stopped ovulation, enlarged ovaries with many cysts, excessive hair growth, and obesity.
Cushing’s Syndrome
Cushing’s Syndrome is an uncommon condition resulting from the body’s exposure to too much cortisol, a hormone produced by the adrenal glands. Since cortisol is a hormone secreted during times of stress, some individuals e.g. those with anxiety disorders, mood disorders, and those dealing with extraordinarily extreme distress may have higher levels than the average individual.
Glucocorticoids, similar in structure to cortisol, are medications prescribed for certain conditions, such as asthma, lupus, and rheumatoid arthritis, and may also lead to a higher likelihood for Cushing’s Syndrome. Other causes of Cushing’s Syndrome include abnormal growths/tumors in the pituitary or adrenal glands. Signs and symptoms of Cushing’s Syndrome include obesity; a round, moon-shaped face; fatigue; high levels of blood glucose; hypertension; a hump between the shoulders, in the upper back; and anxiety. So cushing’s syndrome is one factor that causes of obesity.
Posted at August 23, 2009, Filed Under
