Doing All The Right Things, But Not Losing Weight: Could It Be Your Thyroid?

You’ve started a healthy eating plan, you’ve got a great exercise program that feels manageable, you’re active throughout each day, and you’re getting eight hours of sleep a night. But you’re not seeing all your hard work pay off on the scale. What else is there to do when you’re diligently working toward a goal but still not losing weight?

If you’ve heard that your thyroid gland might be to blame, you’re not alone. It’s a popular question in the Fitbit community, among those who just can’t seem to shed the desired pounds. According to the American Thyroid Association, about 20 million people in the United States have a thyroid problem; roughly 12 percent will develop one over the course of a lifetime.

Thyroid issues are a crucial component of your ability to lose or gain weight. “The thyroid gland makes thyroid hormone, which is a hormone contributing to your overall metabolic rate,” says Michael Langan, MD, FACP, who specializes in internal medicine at The Ohio State University Wexner Medical Center.

Here, Langan walks you through everything you need to know about the thyroid and its impacts on weight gain and loss.

A thyroid might be underactive or overactive. Langan says that underactive thyroid, or hypothyroidism, is when the thyroid is “underfunctioning” and not producing enough thyroid hormone. The symptoms include:

• Difficulty losing or maintaining weight

• Weight gain

• Swelling in legs

• Lethargic

• Hair loss

• Hair texture change

• Slow heart rate

• Cold intolerance

• Constipation

It’s also possible your thyroid might be overactive, which means it’s high-functioning and “producing too much thyroid hormone,” says Langan. The symptoms of hyperthyroidism are:

• Weight loss

• Loose stools

• Rapid heart rate

• Anxiety/jitters

• Insomnia

While it’s good to be aware of both high and low functioning thyroid symptoms, hypothyroidism is the condition that commonly impacts your ability to lose weight.

A number of factors can affect the thyroid’s production of hormones, which can throw your body’s chemistry and metabolic processes out of whack. In underactive thyroid of hypothyroidism, which often impacts a person’s ability to lose weight, common causes are an autoimmune disease, thyroid surgery, radiation therapy, or certain medications. Women are five times more likely to have a thyroid issue than men.

A primary care physician can diagnose a problem with the thyroid. “I’ll typically start by asking the patient a series of questions if thyroid is a concern,” he says. “I’ll examine the neck to see if the thyroid is enlarged, and then usually order a TSH [thyroid-stimulating hormone] blood test.” The test will measure the free levels of thyroid hormone. If your levels are low, you’re hypothyroid — which might be a reason you can’t lose weight.

If you are diagnosed with hypothyroidism, the treatment is relatively straightforward. “If your thyroid is low-functioning, we will essentially give you a medication that is a thyroid hormone replacement,” says Langan. The medication, levothyroxine, will need to be taken lifelong; there is no cure or surgery to increase hormone production once the thyroid’s natural production has dropped off.

Many people are clued into a potential thyroid issue when they’re looking to lose weight and can’t. “If you have a disciplined diet and exercise plan, but you’re not seeing any results in six to eight weeks, then it’s time to see your doctor,” says Langan. “But usually people with a thyroid problem aren’t just experiencing an inability to lose weight; they are usually experiencing two to three other symptoms of a thyroid problem, as well.” If you’re noticing a trifecta — like weight gain, fatigue and constipation, for instance — that’s usually a big clue for hypothyroid.

And while you should definitely be mindful of problems losing weight, don’t be afraid to visit your doctor earlier. “If you’re looking to start a weight loss regimen, your doctor can help you design the right plan for you in terms of diet and exercise,” Langan says, noting someone who’s had knee surgery, for example, may require specific changes for physical activity. “You can see your primary care physician right off the bat.” And you can get your thyroid function checked out before you begin to try and lose weight.