Is Your Thyroid Stopping You From Losing Weight?

True Protein Blog Avatar Fallback reviewed by our Nutrition Team 30 November 2018
Is Your Thyroid Stopping You From Losing Weight?

Low energy levels, weight gain and feeling like you’ve got a slow metabolism are common complaints of a sluggish thyroid. Thyroid dysfunction is more common in women and current statistics show that one million Australians have an undiagnosed thyroid disorder1.

An untreated or misdiagnosed thyroid condition can be taxing to a healthy lifestyle. We explore the common disorders of the thyroid gland to help decide if it’s time to speak to your doctor.

Where is my thyroid and what does it do?

The thyroid is a butterfly-shaped gland that is located in the front of your neck and below your larynx (near your Adam’s apple). The thyroid is mainly responsible for producing hormones that assist in regulating many vital chemical processes in the body to sustain life.

The thyroid gland is controlled by the hypothalamus and the pituitary gland and is part of your body’s endocrine system. It is responsible for producing three hormones; triiodothyronine, also known as T3, tetraiodothyronine, also called thyroxine or T4, and calcitonin2.

The thyroid gland and these three hormones specifically function to:

  • Assist regulation of your energy levels and metabolism, specifically your basal metabolic rate (BMR)

  • Assist regulation of body temperature

  • Assist regulation of your pulse, heart rate and cholesterol levels

  • Assist your body’s ability to develop muscle mass and maintain body weight

  • Regulate blood calcium and phosphate levels

  • Assists in normal bone remodelling/metabolism

  • Promote healthy growth and development in children

  • Promote healthy growth of the brain in the foetus

What are common disorders of the thyroid gland?

Disorders of the thyroid gland relate mostly to under- or over-production of thyroid hormones which may start without any symptoms and later progress to other serious and systemic issues. Hyperthyroidism and hypothyroidism are two common thyroid disorders. Despite sounding similar their effects on the body are completely different.

What is hyperthyroidism?

Hyperthyroidism is commonly called an overactive thyroid as the prefix hyper means ‘over’ which appropriately describes the functioning of the thyroid as ‘sped-up’ and so it produces too many hormones. The imbalance can create a vast range of symptoms.

What are the symptoms of an overactive thyroid or hyperthyroidism?

The Australian Thyroid Association suggests that if you suffer from hyperthyroidism, your symptoms may include:

  • Weight loss and an increased appetite

  • Loose bowel motions or diarrhoea

  • Excessive sweating

  • Difficulty sleeping

  • Heart palpitations

  • Hand tremor

  • Tired and weak muscles, particularly around the upper arms and thighs

  • Enlarged thyroid gland

  • Menstrual changes and/or decreased fertility

  • Restlessness/nervousness

  • Feeling emotional or irritable

  • Shortness of breath

  • Protruding or staring eyes

What causes hyperthyroidism?

According to the American Thyroid Association, the most common cause of hyperthyroidism is due to an overproduction of thyroid hormone by the thyroid gland. This condition is also known as Graves’ disease, which is an autoimmune disorder caused by antibodies in the blood that ‘turn on’ the thyroid and cause it to grow and secrete too much thyroid hormone.

Early diagnosis and appropriate treatment of Graves’ disease is essential, as it can have adverse effects on heart function, bone structure and eye health.

Other inflammatory conditions, excessive iodine or thyroid hormone preparations/medications can also cause hyperthyroidism.

What is hypothyroidism?

Hypothyroidism is commonly called an underactive thyroid as the prefix hypo means ‘under’, which appropriately describes the functioning of the thyroid as slow or sluggish and so it produces too little hormones. The imbalance can create a vast range of symptoms.

What are the symptoms of an underactive thyroid?

The Australian Thyroid Association suggests that if you suffer from hypothyroidism, your symptoms may include:

  • Tiredness, fatigue or lethargy

  • Weight gain and fluid retention

  • Low mood or depression

  • Sleep disturbances

  • Thinning hair and/or eyebrows

  • Always feeling cold or increased cold sensitivity

  • Dry skin

  • Constipation

  • Poor concentration

  • Muscle weakness and pain

  • Enlarged thyroid known as a goitre

  • Low libido or decreased fertility

  • Menstrual changes

What causes hypothyroidism?

There are many reasons as to why the thyroid gland is not producing enough thyroid hormones. Worldwide, iodine deficiency is the most common cause of hypothyroidism3. In Australia and America, where iodine deficiency isn’t as prevalent, autoimmune disease is the most common cause of an underactive thyroid, specifically a condition called Hashimoto’s thyroiditis1,4. Symptoms are usually progressive as thyroid function deteriorates.

It is estimated that hypothyroidism affects 10 times more women than men, and the risk is increased as we get older1.

What is iodine?

Iodine is an essential trace element found in various foods including oysters, kelp/seaweed, tinned salmon, dairy milk, cheese and eggs as well as drinking water and soil. Iodine plays an integral role in the health of your thyroid gland and specifically the thyroid hormone called thyroxine or ‘T4’. The amount of iodine in whole foods can vary greatly depending on the amount of iodine in the soil, the season when the food is grown and processing techniques.

Iodine deficiency in Australia

Iodine deficiency is the most common yet preventable cause of intellectual disability in the world. In Australia, iodine deficiency is becoming an increasingly common cause of thyroid health problems. Research shows that school children and pregnant and breastfeeding women are suffering from mild to moderate iodine deficiency1.

Nutrition Australia stresses the importance of obtaining iodine through the food supply. One reason why iodine deficiency has re-emerged in Australia is due to the introduction of new practices of sanitisation in the dairy industry and a decline in use and consumption of iodised salt.

According to the National Health and Medical Research Council (NHMRC), Australian women that are pregnant or breastfeeding are not getting enough iodine. A deficiency is of particular concern during pregnancy because abnormal functioning of the mother’s thyroid can have a negative impact on the unborn baby’s nervous system, and can increase the risk of congenital iodine deficiency syndrome and infant mortality.

In 2009, Australia’s food authority, FSANZ, implemented mandatory fortification of iodised salt in the production of bread to lift the intake of iodine nationwide. Only bread was chosen so as not to oversupply or overdose iodine. Unfortunately, this strategy may not have been as effective as initially thought considering the rise of gluten-free, low-carb, paleo and other dietary trends that reduce or avoid bread.

What are the treatments for thyroid conditions?

Thyroid conditions extend beyond hyper- and hypothyroidism to describe other conditions including thyroid cancer. Due to the seriousness and complexity of thyroid conditions all initial investigations and advice regarding diagnosis and treatment options should be guided by your doctor and likely a specialist referral to an endocrinologist, who is a trained medical professional that specialises in the endocrine system.

Depending on the diagnosis, treatment regimes may involve medication of thyroid hormones, dietary strategies to supplement or avoid specific nutritional components such as selenium, iodine, soy and zinc. More severe conditions could involve surgery and radiotherapy.

Weight gain and hypothyroidism

Weight gain is a common complaint and often a motivating reason as to why people with an underactive thyroid initiated medical investigations with their doctor. Research has found that lower thyroid hormones and hypothyroidism is associated with a lower basal metabolic rate (BMR) or energy expenditure at rest4. Weight gain associated with hypothyroidism is complex, and not always related to excess fat, yet rather an excess accumulation of salt and water4. Depending on the severity of hypothyroidism, 2-5kg body weight may be attributed to thyroid dysfunction.

Extreme weight gain attributed solely to thyroid dysfunction is rare4. In saying that, other issues can be a contributing factor to excessive weight gain, particularly if weight gain appears to be the only symptom of hypothyroidism. A detailed assessment of dietary habits, overall energy intake and exercise frequency should be explored through a referral to an Accredited Practising Dietitian.

How do I lose weight if I have hypothyroidism?

Hormonal balance, metabolic rate and weight change is very complex in cases of thyroid dysfunction. Firstly, and most importantly, a medical condition needs to be managed by medical professional. Your doctor will advise you on appropriate treatment options depending on your individual needs and severity of hypothyroidism.

When your thyroid hormones and medical condition is stabilised, then day-to-day weight loss strategies are very similar to those of others trying to lose weight with a normal functioning thyroid. Key areas to consider:

  1. Aim for an energy deficit in your diet - Watching you portion sizes, increasing your intake of vegetables and decreasing your intake of energy-dense junk foods will help reduce your overall energy intake. Read ‘Perfect Portions: Size Matters’ on our True Life blog for other helpful tips.

  2. Exercise regularly - Healthy eating and regular exercise goes hand-in-hand when looking to lose weight. Ensure you have a well-designed exercise program and follow it!

  3. Build muscle - It is well-known that increasing your lean muscle mass will increase your metabolic rate5. True WPI90 is the perfect companion to resistance training for weight loss and increasing lean muscle mass. Try it today.


  1. The Australian Thyroid Foundation Ltd. 2018. Cited online [28 Nov 2018] from:

  2. Informed Health Online. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006-. How does the thyroid gland work? 2010 Nov 17 [Updated 2018 Apr 19]. Available online from:

  3. Michelle So, Richard J MacIsaac and Mathis Grossmann. Hypothyroidism - Investigation and management. 2012. Australian Family Physician. Volume 41, No.8, August 2012 Pages 556-562.

  4. American Thyroid Association. 2018. Cited online [28 Nov 2018] from:

  5. Speakman, J., & Selman, C. (2003). Physical activity and resting metabolic rate. Proceedings of the Nutrition Society, 62(3), 621-634. doi:10.1079/PNS2003282

IMPORTANT INFORMATION: all content provided here is of a general nature only and is not a substitute for individualised professional medical advice, diagnosis or treatment and reliance should not be placed on it. For personalised medical or nutrition advice, please make an appointment with your doctor, dietitian or qualified health careprofessional.