Thyroid and Weight Gain: The Obesity Cure

The thyroid is associated with body weight as the butterfly-shaped gland in the neck produces a hormone that regulates metabolism.

Those with an overactive thyroid, or hyperthyroidism, can experience unintentional weight loss, while those with an underactive thyroid, or hypothyroidism, can see weight gain.

As many as 30 million Americans are estimated to have thyroid disease, with more than half of them going undiagnosed, according to the American Association of Clinical Endocrinologists.

Almost 5 percent of people have an underactive thyroid, which carries along with it a slowed metabolism, according to Women's Health. The risk of developing hypothyroidism is greatest for women over 50, and symptoms can mimic signs of aging such as hair and skin changes, lack of energy, and forgetfulness, according to AARP.

T4 supplements, also known as Levothyroxine or Synthroid, provide the needed hormones that an underactive thyroid fails to produce. While identifying and treating thyroid disease can make weight management easier, experts warn that it is not a quick fix for obesity.

"Normalizing the thyroid with thyroid hormone will not cause the weight gain to be reversed," Dr. Marilyn Tan, chief of Stanford Endocrine Clinic, said, according to Women's Health. "To lose that weight, you actually need to work at it, which I know seems very unfair because you just gained it easily."

Dietician Sherri Findley recommends those trying to lose weight eat more foods closest to their natural states, according to Women's Health. Common problems for those with hypothyroidism trying to lose weight include consuming too many calories, not consuming enough calories, lack of exercise and skipping meals, Findley said.

Other hormones, proteins and chemicals also play a role in body weight, and it is difficult to predict how thyroid disease and treatment might affect weight.

Dr. Mark Lupo, a thyroid specialist, said that while it is common for patients with hypothyroidism to gain 10 or 20 pounds, "someone who comes to me weighing 300 pounds has other problems," AARP noted.

The American Thyroid Association said treatment of hypothyroidism can bring about small weight loss, but many patients will see no significant weight loss from the treatment. Once treated, their ability to lose or gain weight will be the same as those without thyroid problems.

While it may be tempting to boost levels of thyroid hormone above normal to lose weight, the American Thyroid Association cautioned that the weight is usually regained once hormone levels are returned to normal and the excessive hormones can cause muscle protein loss and other metabolic problems.

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