"Many believe that they are overweight because of an underactive thyroid. In most cases, excessive calorie intake and insufficient physical activity are behind obesity and unfavorable body composition. However, several conditions and medications can also cause weight gain, such as chronic stress, hormonal imbalance due to lack of sleep, sleep apnea syndrome ('night snoring'), certain antidepressants, antihistamines, sulfonylureas, and beta-blockers. Rare congenital genetic disorders and brain-related illnesses may also lead to weight gain, though psychological factors like stress eating or reward-based eating and rheumatological issues hindering movement are much more common," explains Dr. Bajnok. "In most cases, a detailed investigation of these factors, combined with an individually tailored diet and exercise therapy, as well as medical or surgical interventions if necessary, can yield results."
Thyroid hormones affect nearly every cell in the body, influencing body weight and composition in several ways. They regulate basal metabolism, oxygen consumption, heat production, and spontaneous motor activity. They also impact fluid and salt balance and the functioning of muscles and joints.
The signs and symptoms of hypothyroidism develop slowly and are often nonspecific. They include weakness, fatigue, drowsiness, memory problems, constant cold sensation, constipation, dry skin, thinning hair, brittle nails, thinning eyebrows, a hoarse or deepening voice, muscle pain or stiffness, painful or swollen joints, menstrual irregularities, decreased libido, infertility, slower heart rate, high blood pressure, shortness of breath, mood disorders, an enlarged thyroid gland, elevated cholesterol levels, and anemia. Long-term effects can include cardiovascular diseases or worsening of existing conditions and increased bone fragility.
While many have heard about weight gain as a symptom of hypothyroidism, it only occurs in about half of patients, with an average increase of just 3 kg. Hypothyroidism is significantly more common in women, making the associated weight gain more likely in this group. However, a significant 10% weight gain cannot be solely attributed to thyroid dysfunction.
Only 10-15% of obesity cases are caused by secondary factors unrelated to lifestyle, including hormonal imbalances. In addition to thyroid diseases, other leading endocrine causes include insulin overproduction and resistance (e.g., diabetes) and low sex hormone levels (e.g., menopause). Rare causes include cortisol overproduction and growth hormone deficiency. Stress and poor sleep also contribute to hormonal imbalances, although these may not always be detected through blood tests.
Hypothyroidism can be treated with medication prescribed and adjusted by a specialist after a few simple tests. The condition is caused by a deficiency of the hormone thyroxine, which is replaced through treatment. Regular follow-ups are essential during the initial phase of treatment, as it may take time to achieve proper hormone levels. Annual check-ups are sufficient thereafter.
Will weight normalize after hypothyroidism is treated? Unfortunately, not always. The main reason is that significant weight gain is not caused solely by hypothyroidism, so resolving it does not automatically restore weight to normal levels. A dedicated approach to diet and exercise is still necessary, as in other cases. Even after proper thyroid hormone replacement, muscle weakness may persist for months, temporarily affecting physical performance.
In addition to medication, diet also plays a role. There is no specific thyroid diet, but certain things should be kept in mind. Raw cruciferous vegetables, canola, soy, carrots, and walnuts inhibit iodine absorption, so their consumption should be reduced. For this reason, a cabbage soup diet is not the best choice for weight management. Instead, focus on consuming seafood, drinking 2-3 liters of water daily, and ensuring a fiber intake of 35 grams per day to prevent constipation associated with hypothyroidism.
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In Hungary, every second person struggles with weight problems, but fewer than 1 in 100 people have hypothyroidism, which can be detected with a simple blood test. About half of patients with hypothyroidism experience weight gain despite a reduced appetite, with an average increase of 3 kg. Dr. Éva Bajnok, an obesity specialist at Liv Duna Medical Center, notes that a 10% weight gain cannot solely be attributed to thyroid dysfunction.
* Liv Editorial Board .
