From Hormones to Health: Your Guide to Thyroid Function and Maintaining a Healthy Weight

If you’re a client of mine, follow me on Instagram, or receive my newsletters, you’re likely familiar with the thyroid gland and its important functions. Located at the front of your neck, the thyroid may seem small, but it plays a critical role in nearly every aspect of our well-being. Thyroid hormones affect almost every organ system in the body, including the heart, nervous system, bones, digestion, and metabolism.

Thyroid hormones act like messengers, telling your cells to work harder. Once they attach to specific receptors inside your cells, they activate genes that increase both metabolic rate (how fast your body burns energy) and thermogenesis (heat production). In simple terms, thyroid hormones keep you energised, regulate body temperature, and help maintain a healthy weight.

Thyroid Disorders: A Women's Health Issue

Thyroid conditions disproportionately affect women, with hypothyroidism being the most common thyroid disorder in Australia, impacting 1 in 33 people. Globally, thyroid disorders affect women ten times more than men, and the likelihood of developing hypothyroidism—an underactive thyroid—increases with age. For women, this is partly due to the thyroid’s relationship with hormones like oestrogen and progesterone.

Awareness of thyroid health has been rising in recent years as people begin to understand how much this small gland affects everything from mood to weight management. If you’ve been struggling with unexplained weight loss or stubborn weight that won’t shift despite a healthy diet and regular exercise, your thyroid might be the missing piece of the puzzle.

What Is the Thyroid Gland?

The thyroid gland, a small but powerful organ located at the base of your neck, is often described as the body’s energy manager. Its primary function is to regulate metabolism—the process by which your body converts food into energy. This directly impacts how efficiently your body burns calories and maintains energy levels.

Additionally, the thyroid influences heart rate and body temperature, keeping everything in sync with your body’s needs. A well-functioning thyroid is like a well-oiled machine, ensuring your metabolism runs smoothly, maintaining steady energy, and helping regulate weight. When your thyroid is in balance, you feel it.

Key Thyroid Hormones: Thyroxine (T4) and Triiodothyronine (T3)

The thyroid produces two key hormones: Thyroxine (T4) and Triiodothyronine (T3). T4, the primary hormone produced by the thyroid, is often referred to as a prohormone because it converts into the more active form, T3, in various tissues. T3 has the most direct impact on metabolism, playing a vital role in energy levels, growth, and development.

 T4 to T3 conversion is crucial for thyroid function. While T4 is produced in larger quantities, it’s T3 that binds to the body’s cells to regulate metabolism. This conversion occurs mainly in the liver and kidneys, and any disruption in this process can lead to symptoms like fatigue, weight changes, or temperature regulation issues.

Thyroid Health and Weight Management

1. Hypothyroidism and Weight Gain

  Hypothyroidism occurs when the thyroid produces too little thyroid hormone, leading to a slower metabolism. This can result in weight gain, even if your diet and exercise habits haven’t changed. Fatigue and low energy are also common, making it harder to stay active and manage weight.

2. Hyperthyroidism and Weight Loss

 Hyperthyroidism, marked by excessive thyroid hormone production, speeds up metabolism, often resulting in weight loss despite an increased or normal appetite. While weight loss may seem appealing, hyperthyroidism can also lead to muscle wasting, malnutrition and osteoporosis due to rapid calorie burning. Proper treatment and nutrition are key to preventing these complications.

3. Balancing Thyroid Function 

Thyroid hormones, particularly T4 and T3, regulate your basal metabolic rate (BMR), or how much energy your body uses at rest. Whether your thyroid is underactive or overactive, it can disrupt this balance and lead to weight management challenges.

Managing Thyroid-Related Weight Issues

Managing weight issues related to thyroid conditions begins with an accurate diagnosis and appropriate medical treatment. If you suspect a thyroid disorder, it's essential to ask your healthcare provider for a comprehensive thyroid panel, not just a TSH test. Here’s why:

• T4 and T3: These are the primary hormones produced by the thyroid. T4 is a storage form that converts to T3, the active form responsible for regulating metabolism. Low T3 levels can cause symptoms even if TSH is within the normal range.

• Reverse T3 (rT3): This is an inactive form of T3 that can block the effects of active T3, leading to symptoms of hypothyroidism despite normal T4 or TSH levels. Stress and illness can drive up rT3 production, creating imbalances.

• Thyroid antibodies (TPOab, TgAb, TSHRAbs): These tests are crucial for detecting autoimmune thyroid conditions like Hashimoto’s or Graves’ disease. Autoimmune thyroid issues often go undiagnosed because they don’t always cause immediate changes in TSH, leading to missed diagnoses if antibody testing is not included.

Many people remain undiagnosed because TSH alone can appear normal, especially in early stages or with subclinical conditions. A full panel allows for a more nuanced understanding of thyroid function and autoimmune activity, ensuring more accurate diagnoses and tailored treatments, particularly for women who are more prone to autoimmune thyroid conditions.

Medical Treatment Options for Thyroid Conditions in Australia

Hormone Replacement Therapy for Hypothyroidism

In Australia, hypothyroidism is usually treated with levothyroxine, a synthetic form of T4 that helps normalise hormone levels. The body converts T4 to T3 as needed. Regular blood tests are used to monitor TSH and sometimes T4 levels, adjusting dosages accordingly.

Medications or Radioactive Iodine for Hyperthyroidism 

 Hyperthyroidism is typically treated with medications like methimazole or propylthiouracil (PTU) to reduce hormone production. In more severe cases, radioactive iodine (RAI) is used to destroy overactive thyroid cells, stabilising hormone levels. However, RAI may result in hypothyroidism, requiring subsequent hormone replacement.

Are Medical Treatments Always Necessary?

Yes and no—it depends on the severity and specific condition. Medical treatments are often necessary for hyperthyroidism to prevent complications like heart issues, osteoporosis, or thyroid storm (a life-threatening emergency). In other cases, lifestyle changes, diet adjustments, herbs and nutrients can help support thyroid health.

Nutritional Strategies to Support Thyroid Health

Certain nutrients, such as iodine, selenium, and zinc, are vital for thyroid function. Incorporating foods like fish, nuts, and whole grains can support hormone production and overall thyroid health. However, be cautious with iodine supplements, as excess intake may worsen thyroid conditions. Always consult your healthcare provider before making supplement changes.

Exercise and Thyroid Health

Exercise can be an effective way to support thyroid function and manage weight. For hypothyroidism, combining aerobic and strength-training exercises can help improve metabolism. For hyperthyroidism, moderate exercise can help manage symptoms and prevent muscle loss. The key is to choose activities you enjoy so you’ll stick with them long-term.

Herbs for Thyroid Conditions

Herbs can complement thyroid treatments by balancing hormones and reducing inflammation. Withania Somnifera (Ashwagandha) may support hypothyroidism by improving thyroid function and stress resilience. Fucus vesiculosus (Bladderwrack), rich in iodine, can help in cases of iodine-deficient hypothyroidism. For hyperthyroidism, Melissa officinalis (Lemon balm) and Ajuga reptans (Bugleweed) can help reduce thyroid activity and ease symptoms like anxiety. Always consult your healthcare practitioner, naturopath or herbalist before taking herbs for your thyroid condition.

Conclusion

Understanding the connection between thyroid health and weight management is vital for achieving long-term wellness. By seeking accurate diagnoses, proper treatments, and making lifestyle changes, you can take control of your thyroid health and reach your weight management goals.

If you suspect thyroid issues are affecting your weight or overall health, book a discovery call with us. We offer personalised insights and tailored approaches to help you regain balance and optimise your thyroid function.