When the thyroid is functioning properly, it absorbs the iodine found in many of the foods we eat and converts it into two kinds of hormones: T3 and T4. These two hormones are released into the bloodstream to control and monitor all the body’s metabolic processes. However, if the thyroid produces too much of these two hormones, a condition known as hyperthyroidism occurs. This means the body’s metabolism speeds up abnormally, which can lead to an increased heartbeat (or even heart palpitations), sweating, overheating, fatigue, swelling of the thyroid gland (goiter), hair loss, insomnia, and weight loss.

Hyperthyroidism usually occurs in people between the age of 20-40, as well as pregnant women or any individual undergoing a great deal of stress. One of the most common manifestations of this disorder is Grave’s disease, in which the pituitary gland — the “master” gland located at the base of the brain which controls all the other glands in the body — mistakenly instructs the thyroid to release too many T3 and T4 hormones. The opposite of this condition is of course hypothyroidism, wherein the thyroid does not produce enough of the hormones required to maintain a proper metabolic rate. Ironically, however, many of the symptoms are the same in both conditions.

Although weight loss may seem to be the obvious correlation of an overactive thyroid, recent studies have shown that despite an increased metabolism, many people suffering from hyperthyroidism have in fact actually gained significant amounts of weight, and continued to gain weight after they were treated. This is most likely due to the increased appetite that results from a faster metabolism, in addition to an inability to burn off the extra calories because of weakness, apathy and depression — three other symptoms associated with this disorder.

Another possible explanation for the weight gain in an individual with hyperthyroidism could be that since the overabundance of T3 and T4 originally prevented the patient’s body from ever regulating itself, the individual can no longer properly monitor his or her caloric intake, even with normalized hormone levels. Making a concerted effort to maintain a proper diet and a strict exercise regimen can help alleviate some of the weight gain experienced by people with hyperthyroidism.

While treatment of hyperthyroidism might involve the use of drugs such as radioactive iodine (or other forms of medication designed to slow down the production of T3 and T4 by the thyroid), or even having part of the thyroid removed surgically, some nutritional experts recommend a diet high in Omega-3 fatty acids, vitamin C and calcium. Certain foods known to inhibit thyroid overproduction include cauliflower, beans, green leafy vegetables and soy. Herbs such as motherwort, turmeric and bugleweed have also been known to stabilize the thyroid gland, but of course one should always check with one’s health care practitioner before attempting to diagnose or especially to treat an ailment of this type of severity.

Common symptoms of hypothyroidism include weight gain, fatigue, feeling cold when others are comfortable or warm, brittle nails and dry skin, and hair loss. Irregularity of menstrual periods, constipation, depression, and swelling in the lower legs are other symptoms of hypothyroidism. As the thyroid gland works harder to produce more thyroid hormones it enlarges and becomes palpable in the neck. This is called a thyroid goiter. Hypothyroidism is diagnosed with blood tests measuring thyroid stimulating hormone or TSH from the pituitary gland along with thyroxin (T4) and triiodothyronine (T3) released from the thyroid gland. A sonogram of the thyroid will reveal whether the gland is diffusely enlarged or if there are nodules present. A thyroid scan using radioactive iodine will determine if areas of the enlarged gland are “cold” or do not take up the iodine. Cold nodules may indicate a thyroid cancer.

The most common cause of hypothyroidism is thyroiditis or an inflammation of the thyroid gland. Other causes include inadequate production of thyroid stimulating hormone from the pituitary gland, surgical removal of all or part of the thyroid gland, or drugs that affect thyroid function. Once hypothyroid disease is diagnosed thyroid hormone replacement usually in the form of levothyroxine is begun to reverse the effects of hypothyroidism.

A major symptom of hypothyroidism is weight gain. The mechanism of weight gain in people who are hypothyroid is two fold. As a hormone that controls cellular metabolism in every cell in the body it is easy to see that lack of thyroid hormone will cause a lower cellular metabolism. This leads to both a lower metabolic rate and slower burning of calories and also fatigue. By products of fatigue are lower activity levels resulting in fewer calories burned and increased consumption of glucose rich foods in an effort to increase energy.

Patients often feel that once hypothyroidism is diagnosed and thyroid hormone replacement is begun weight loss will be simple. This is not the usual case. It takes an average of three to four weeks for the thyroid hormone to reach a steady state in the body. As the patient begins to feel better both eating habits and exercise levels need to change in order to lose the excess weight.

Patients who have gained weight may also experience something called metabolic resistance. Even after thyroid levels have been corrected it is difficult for these patients to simply reduce calories and lose weight. Their metabolism needs to be stimulated. The easiest way to stimulate the body’s metabolism is with vigorous exercise consisting of at least thirty minutes a day five days each week of aerobic activity. Patients who have been hypothyroid need to begin slowly under a doctor’s supervision but persistence will pay off with weight reduction.

Other important aspects of reversing weight gain once the hypothyroidism has been diagnosed is to make sure that the thyroid replacement is adequate. Since the TSH level is used to measure the adequacy of thyroid replacement this level should be in the low normal range. The range is 0.5 to 5.5 but most experts suggest thyroid hormone replacement should keep the level between 1.0 and 2.0.