Hypothyroidism and weight gain

Our body uses food as fuel. Metabolism is the consumption of this “fuel”  by your body by breaking down food and converting it into energy. The rate at which this occurs is different for each individual and is called metabolic rate. Thyroid hormones directly control the metabolism in the body.

What's Inside?

What is the science behind it?

The thyroid directly controls the metabolism of your body by using iodine in our blood and incorporating it into the thyroid hormones. Every tissue of your body is dependent on thyroid for controlling its metabolism.
The two main thyroid hormones produced by the thyroid are T3 (triiodothyronine) and T4(thyroxine).

When there is too little thyroid hormone in your blood, the hypothalamus signals the pituitary gland to produce more Thyroid Stimulating Hormone(TSH) which in turns triggers a response in the thyroid to produce more hormones.

The thyroid hormones control some important functions in the body, such as:

  • Body weight
  • Heart rate
  • Menstrual cycles
  • Central and peripheral nervous systems
  • Body temperature
  • Muscle strength
  • Cholesterol levels

How does thyroid influence weight?

  • When there is too much thyroid hormone in your body, you may have “Hyperthyroidism” which is characterised by “fast metabolism” and a corresponding weight loss, along with multiple other symptoms.
  • Similarly, when there is too little thyroid hormone in the body, you may have “Hypothyroidism” or an underactive thyroid that is essentially responsible for “slow-metabolism”.
  • The gain in weight experienced may be a result of the reduced metabolism caused by an underactive thyroid.
  • This extra weight gained may not be directly associated with fat accumulation. The body stores excess salt and water which is reflected as extra weight.
  • In general, hypothyroidism does not account for a massive increase in weight. It mostly leads to a weight increase of 2 to 5 kgs.

How do I know if I may have hypo-thyoidism from my present symptoms?

Hypothyroidism is often associated with other visible symptoms as well. If you have experienced an unexplained weight-gain with the same diet and physical exercise level and are experiencing any of the symptoms mentioned below, you may have an under-active thyroid. If that is the case, it is recommended that you take a hormonal test and consult a physician for complete diagnosis. 

Symptoms commonly associated with hypo-thyroidism are:

How will my physician diagnose if I have hypo-thyroidism?

There are 3 steps involved in a diagnosis process when you visit a physician.

  • Recording a patient’s health history
    The physician will ask you details about how much weight you have gained over how much time and what all symptoms you have been seeing other than weight gain.

  • Physical examination
    The physician will then check for any signs such as swelling in the neck, difficulty in swallowing, low pulse etc.

  • Lab tests
    The physician will check and rule out causes of thyroid abnormality based on results on lab tests. Tests that are usually performed are T3, T4, TSH and TPO antibodies. A prolactin test (PRL) may also be requested in some cases, as hypothyroidism and hyperprolactinemia are commonly associated together.