Weight gain is a complex process that involves multiple factors, but there is one gland in particular that plays a major role in regulating metabolism and appetite – the thyroid gland. An underactive thyroid, known as hypothyroidism, is one of the most common causes of unexplained weight gain. Let’s take a closer look at how the thyroid affects weight and what you can do if you suspect your thyroid is to blame for those stubborn extra pounds.
How does the thyroid gland affect weight?
The thyroid gland is a butterfly-shaped organ located in the front of your neck that produces thyroid hormones. These hormones help regulate many important body functions including metabolism, heart rate, mood, and growth and development. Thyroid hormones essentially act as the gas pedal for your metabolism – they determine how many calories your body burns at rest and during activity. When thyroid hormone levels are low, as in hypothyroidism, your metabolism slows down. This means you burn fewer calories throughout the day. A sluggish metabolism leads to weight gain over time if you continue to eat the same amount of food. Here’s a quick overview of how hypothyroidism can promote weight gain:
- Fewer calories burned at rest and during exercise/activity
- Decreased fat breakdown
- Sluggish digestion
- Fluid retention
- Fatigue and low energy for exercise
- Increased appetite
As you can see, many factors are at play. Even if you eat well and exercise, low thyroid hormone levels make it extremely difficult to lose weight through diet and activity alone. The good news is weight loss is possible with proper hypothyroidism treatment.
What causes hypothyroidism?
There are several potential causes of an underactive thyroid gland including:
- Hashimoto’s disease – This autoimmune disorder damages the thyroid gland causing decreased hormone production over time. It is the most common cause of hypothyroidism.
- Thyroiditis – Thyroid inflammation from autoimmune diseases or viral infections can disrupt normal thyroid function.
- Radiation treatment – Radiation used to treat cancers of the head and neck can affect the thyroid.
- Medications – Drugs like amiodarone, lithium, interferon alpha can impact thyroid function.
- Pregnancy – Some women develop hypothyroidism during or after pregnancy (postpartum thyroiditis).
- Congenital hypothyroidism – A small number of babies are born with an underactive thyroid.
- Iodine deficiency – Consuming too little iodine can cause hypothyroidism over time.
- Pituitary disorder – The pituitary gland produces TSH to stimulate thyroid hormone production. Problems with the pituitary can disrupt this process.
- Removal of thyroid gland – Thyroidectomy surgery for hyperthyroidism or thyroid cancer can cause hypothyroidism.
Hashimoto’s thyroiditis is responsible for most cases of hypothyroidism. With Hashimoto’s, the immune system mistakenly attacks and destroys the thyroid gland. This causes inflammation and lowers the thyroid’s ability to produce hormones over months or years. Hashimoto’s primarily affects middle-aged women but can occur at any age.
Hypothyroidism symptoms
Hypothyroidism develops gradually over time in most people. At first you may not notice symptoms or attribute them to other causes like aging, stress, or the busy nature of modern life. As thyroid hormone levels continue to fall, symptoms tend to worsen. Common signs and symptoms include:
- Fatigue, tiredness, sluggishness
- Weight gain or difficulty losing weight
- Constipation
- Increased sensitivity to cold
- Muscle weakness, aches, tenderness
- Stiff or sore joints
- Depression, sadness
- Impaired memory and concentration
- Dry, thinning hair and skin
- Muscle cramps
- Elevated blood cholesterol
- Heavy, irregular periods in women
- Infertility
Keep in mind many of these symptoms can have other explanations. Fatigue and problems with memory and focus are common complaints with a busy, stressful lifestyle. Always discuss persistent or concerning symptoms with your healthcare provider.
Who is at risk for hypothyroidism?
Certain factors increase your risk of developing hypothyroidism. These include:
- Female gender – Women are much more likely to have thyroid problems.
- Age over 60 years old
- Autoimmune diseases like type 1 diabetes or rheumatoid arthritis
- Family history of thyroid disease
- History of thyroid problems after pregnancy (postpartum thyroiditis)
- Radiation exposure to the head or neck
- Treatment with amiodarone, lithium, interferon alpha, or other drugs that affect thyroid function
- Selenium or iodine deficiency
- Obesity
Women over age 60 with a family history of thyroid disease are at highest risk. However, hypothyroidism can affect anyone at any age. If you experience suspicious symptoms, do not hesitate to see your doctor.
Diagnosing hypothyroidism
If hypothyroidism is suspected based on risk factors and symptoms, your doctor will order blood tests to measure levels of thyroid hormones. This includes thyroid-stimulating hormone (TSH) and thyroxine (T4). The most sensitive test is TSH. Typical lab reference ranges are:
- Normal TSH: 0.5 to 4.5 to 5.0 mIU/L
- Normal Free T4: 0.8 to 1.8 ng/dL
In hypothyroidism, TSH is elevated while free T4 is low. Your doctor may also check levels of free T3 and thyroid antibodies to identify autoimmune thyroiditis. The earlier hypothyroidism is caught, the easier it is to treat. Be sure your doctor evaluates your symptoms along with thyroid lab tests. People can experience symptoms even if their TSH is only mildly elevated.
Treating hypothyroidism
Hypothyroidism is easily treated with oral thyroid hormone replacement medication. The most commonly prescribed drug is levothyroxine (Synthroid, Levoxyl). This synthetic T4 restores normal thyroid hormone levels, reversing the metabolic changes that cause weight gain. Treatment benefits include:
- Boosts basal metabolic rate
- Normalizes fat breakdown
- Relieves constipation
- Improves energy, mood, and mental focus
- Regulates cholesterol
- Decreases cardiovascular risk
When on proper thyroid medication, most people notice improvements in hypothyroid symptoms within weeks. However, weight loss tends to be more gradual. It may take several months to normalize your metabolism and drop excess pounds. Patience and consistency are key. You should never abruptly stop thyroid medication unless advised by your healthcare provider.
Tips for losing weight with hypothyroidism
Here are some tips to help accelerate weight loss once your hypothyroidism is treated:
- Ask your doctor to check TSH and T4 every 6 to 8 weeks when first starting treatment. This ensures you are on the right thyroid medication dose.
- Take thyroid medication correctly on an empty stomach and avoid interfering medications, supplements and foods.
- Engage in regular cardiovascular exercise to help burn calories and build muscle.
- Follow a healthy low-calorie diet focusing on lean proteins, fruits, vegetables and whole grains.
- Drink plenty of water and reduce salt intake to decrease fluid retention.
- Consider adding Selenium or Iodine if deficient.
- Get 7 to 9 hours of sleep nightly.
- Manage stress levels with relaxation techniques.
Remember weight loss still requires consistent lifestyle changes in diet and activity even when the thyroid issue is corrected. Work closely with your healthcare team to find the optimal treatment plan for you.
Can you have normal TSH and still be hypothyroid?
In most cases, an elevated TSH over 4.5 to 5.0 mIU/L indicates hypothyroidism. However, some people can still experience hypothyroid symptoms even when their TSH is within the normal range (a condition called subclinical hypothyroidism). This happens because different people require different levels of thyroid hormones to feel well and maintain a healthy weight. For example, one person may feel best with a TSH around 1, while another feels optimal with a TSH of 3. A TSH in the upper end of the normal range may be too high for some. Doctors should take into account thyroid antibody status and clinical symptoms when interpreting thyroid lab work. Treating based on TSH alone is not always sufficient.
Are there alternatives to Synthroid?
For most people, synthetic thyroxine drugs like Synthroid are effective and well-tolerated. However, some individuals do better on alternative thyroid medications or protocols. Options include:
- Natural desiccated thyroid – Contains T4 and T3 derived from porcine thyroid glands.
- Liothyronine (T3) – The active form of thyroid hormone.
- Compounded thyroid hormone – Mixed by a pharmacist, allows custom ratios of T4 and T3.
- Combination therapy – T4 drug paired with some T3.
- Thyroid glandular supplements – Contain thyroid extract from animals.
Always consult your doctor before switching thyroid medication or taking glandular supplements. Self-treating with T3 or animal thyroid can be dangerous. However, some patients feel better with a natural or compounded thyroid alternative under medical supervision.
Can you treat hypothyroidism naturally?
While thyroid hormone replacement is the standard treatment for hypothyroidism, complementary therapies and lifestyle changes may help boost your results. Potential natural remedies include:
- Elimination diets like gluten-free or autoimmune protocol to reduce inflammation
- Selenium – Supplements if selenium deficient
- Iodine – From kelp, fish, eggs, dairy if iodine deficient
- Probiotics – To improve gut health
- Vitamin D – From sun exposure, fatty fish, supplements
- Omega-3 fatty acids – From fish oil, flax seeds
- Zinc supplements
- Guggul – Herbal supplement
- Stress reduction techniques – Yoga, meditation, massage
- More sleep – Aim for 7 to 9 hours nightly
- Exercise – To increase metabolism
A nutritious diet, active lifestyle, and stress relief provide a foundation for hormone replacement to work. Work with a knowledgeable practitioner to determine which natural therapies might complement your treatment. Do not attempt treating hypothyroidism with only dietary changes and supplements.
Can you have normal thyroid levels and still have symptoms?
It is possible to have a normal TSH and free T4, but still experience signs of low thyroid function. As mentioned earlier, different people need different optimal thyroid levels to feel their best. Symptoms may develop even when labs are in the “normal” reference range. Other potential reasons for lingering hypothyroidism symptoms include:
- Conversion problems – Your body cannot convert T4 to the active T3 properly.
- Thyroid resistance – Tissues do not respond as expected to normal thyroid levels.
- Adrenal imbalances – Chronic stress can mimic hypothyroidism.
- Blood sugar swings – Diabetes and insulin resistance cause similar symptoms.
- Pituitary dysfunction – Interferes with TSH signaling.
- Nutrient deficiencies – Low iron, B12, selenium, zinc or vitamin D.
- Toxins – Heavy metals, chemicals can disrupt thyroid function.
Doctors need to look beyond just TSH and consider antibodies, genetics, lifestyle factors and symptoms when evaluating borderline thyroid lab results. Optimal treatment should relieve symptoms and prevent long term risks of low thyroid hormone.
Takeaways
Here are the key takeaways about the thyroid gland and its role in weight changes:
- The thyroid produces hormones T4 and T3 that regulate metabolism.
- Hypothyroidism, from Hashimoto’s or other causes, slows metabolism leading to weight gain.
- Symptoms include fatigue, muscle weakness, dry skin, constipation, and depression.
- Diagnosis is made through TSH and T4 blood tests.
- Treatment involves daily levothyroxine medication to correct hormone deficiency.
- Lifestyle changes in diet and exercise accelerate weight loss once treated.
- Some patients feel better with natural thyroid supplements or T3 combinations.
- Complementary therapies like selenium may provide added benefit.
- Doctors should evaluate those with symptoms despite normal labs for other causes.
If you are struggling with weight gain, fatigue, or other concerning symptoms, do not overlook the possibility of a thyroid issue. Underactive thyroid is easy to miss and often goes undiagnosed. Work with a physician who is thorough and open-minded to find solutions. With proper treatment tailored to your needs, you can get your metabolism back on track and resolve troublesome hypothyroidism symptoms.