**hypothyroidism and thinness** Hypothyroidism is a condition in which your body does not produce enough thyroid hormone. Hypothyroidism occurs for various reasons. Thyroid inflammation (Hashimoto's) is one of the causes of hypothyroidism. Overweight is one of the symptoms of this disease that patients struggle with. Taking hypothyroid pills or levothyroxine by controlling this disease can improve its symptoms. But what reasons can cause lack of weight in hypothyroidism? In this article, we address this question. ### **What are the complications and symptoms of hypothyroidism?** If you have an underactive thyroid that is not treated and controlled, it may lead to various diseases. This disease has various symptoms that can be the same as the symptoms of other diseases, so it can be easily confused with other diseases. As a result, it is very important to recognize it. These symptoms usually develop slowly and you may not realize you have the disease for several years. Common symptoms of hypothyroidism include: - Fatigue - Being sensitive to cold - Weight gain - Constipation - Depression - Muscle pain and weakness - Muscle cramps - Dry skin Brittle hair and nails - loss of sexual desire (sexual desire) - Irregular periods or heavy periods Older people with underactive thyroid may experience memory problems and depression. Children may experience slower growth and development. Adolescents may start puberty earlier than usual. If you have any of these symptoms, see your GP to be tested for hypothyroidism. Facial puffiness, anemia, eyebrow loss, etc. are among the next symptoms of underactive thyroid. ### **Relationship between hypothyroidism and overweight** As mentioned in the symptoms and complications of hypothyroidism, obesity and weight gain is one of the things that you will face in case of hypothyroidism. When the thyroid is underactive, the body's metabolism slows down. In this case, the body burns fewer calories. When levels of key thyroid hormones are low, metabolism—the body's ability to efficiently use energy and oxygen—reduces. This reduced metabolism can lead to fatigue, weight gain, and other metabolic changes that make it harder to maintain a healthy weight. Extensive research shows that thyroid hormone is an important determinant of overall energy expenditure, and low thyroid hormone levels can reduce BMR. BMR is defined as the amount of body energy during a minute, hour or day to maintain basic body functions such as breathing, blood pumping, maintaining body temperature and basic brain function. ### **What is the reason for weight gain in hypothyroidism?** Hypothyroidism may be one of the factors that cause weight gain, but it is not the only factor. For each person, there are different reasons and conditions for weight gain that need to be considered. Decreased metabolism and possibly increased appetite and maintenance of body calories in people with hypothyroidism cause obesity and overweight. Decreased metabolism means a decrease in the rate of energy burning in the body, in other words, the rate of metabolism decreases. Another reason for weight gain in people with hypothyroidism is the increase in body water. This water gain is usually caused by changes in hormonal levels and overall body function, which results in weight gain. ### **The reason for not losing weight in underactive thyroid** In addition to reducing metabolism, which is one of the symptoms of this disease, other reasons can also cause weight gain. Weight loss becomes more difficult in hypothyroidism for the following reasons. As a result, it is better to check the following reasons. #### **increase in stress hormones** Low levels of thyroid hormones can cause increased levels of cortisol (stress hormone), which itself is a factor in weight gain. #### **adrenal insufficiency** Chronic hypothyroidism can also cause hypofunction of the adrenal glands, which in turn reduces the body's metabolism. #### **leptin resistance** Hypothyroidism is one of the most common medical conditions associated with leptin resistance. Leptin is a hormone that regulates hunger levels and makes you feel full. When you eat, leptin is released and sends the message to the brain that you are full. However, sometimes the brain does not respond normally to leptin. This condition, known as leptin resistance, can cause you to eat more even though your body has enough fat stores to meet your energy needs. #### **insulin resistance** In some people, hypothyroidism is associated with disorders such as insulin resistance, which increases the likelihood of being overweight. Thyroid hormones have a significant effect on how the body processes sugar (glucose) and how insulin works in the body. Insulin is a hormone that helps the body regulate blood sugar levels. When you eat, the food turns into glucose. The pancreas then releases insulin, which helps the body process glucose for immediate use or storage. Insulin resistance is a condition in which muscle, fat and liver cells do not respond well to insulin and cannot easily take glucose from the blood. As a result, the pancreas produces more insulin to compensate, leading to high blood sugar levels over time. **How to lose weight with hypothyroidism?** Losing weight in hypothyroidism may seem a bit difficult, but treating hypothyroidism with levothyroxine can improve metabolism and facilitate weight loss. Of course, this process is slow. It is recommended that people suffering from hypothyroidism follow a proper diet, sufficient physical activity and receive alternative treatments such as levothyroxine. In the end, it should be noted that improving the condition of hypothyroidism with appropriate treatment can return the metabolic rate to the normal state and weight loss can start again. However, as we said, hypothyroidism alone is not the main reason for weight gain, and other factors must be considered for each person. **Read more**: **9 tips for losing weight with hypothyroidism** ### **Can hypothyroidism lead to weight loss?** In answer to this question, it should be said that yes, but it is mostly due to a decrease in appetite or a decrease in calorie consumption, a feeling of fatigue, and a decrease in physical activity, which may cause weight loss. Dr. Seyed Ahmad Fanai is a thyroid and parathyroid surgeon and an active member of the American Association of Thyroid Surgeons (ATA). You can contact us for appointment and consultation.