How A Low Calorie Diet Negatively Affects Your Thyroid

Many people attempt to lose weight by eating a very low calorie diet, but not everyone understands the risks associated with extreme low calorie diets for weight loss. Of course there is a time and place for calorie restriction, but when you eat a very low calorie diet for an extended period of time, you set your body up for failure in the long run. It’s important to make sure you are getting enough calories for your body’s needs. The definition of metabolism is the chemical processes that occur within a living organism in order to maintain life. You may or may not know the importance of the thyroid gland in regards to regulating your metabolism, but today we will talk about the mechanism of why and how your metabolism actually slows down from low calorie diets. 

Important Thyroid Hormones

Thyroid Stimulating hormone (TSH) is a hormone that is produced in the pituitary gland and tells your thyroid how much thyroid hormone to produce. High TSH levels are indicative of hypothyroidism (an underactive thyroid) because when your body recognizes that it doesn’t have enough thyroid hormones, it signals the pituitary to produce more TSH to try to stimulate more thyroid hormone production. Low TSH levels are more indicative of hyperthyroid (an overactive thyroid) because the body is recognizing high levels of thyroid hormones and trying to slow down the production by lowering TSH levels. This is an ongoing feedback loop to try to increase or decrease your thyroid hormone production in order to stay within the ideal ranges. 

Thyroxine (T4) and triiodothyronine (T3) are hormones produced by the thyroid gland. T4 is an important thyroid hormone, but most of it is inactive, and goes on to be converted to T3. Cells that have receptors for thyroid hormones are better able to use T3 than T4. These thyroid hormones help regulate your body’s metabolism, or how your body stores and uses energy. These hormones also play a role in muscle control, mood, digestion, heart function, body temperature, and more. 

Subclinical hypothyroidism is defined as having high TSH levels with normal T4 levels. Overt hypothyroidism is diagnosed when TSH levels are high and T4 levels are low. 

How Low Calorie Diets Affect Thyroid Hormones

When you eat an extreme low calorie diet for an extended period of time, this can lower T4 and T3 levels, which slows down your metabolism. Calories are energy, and if you aren’t consuming enough calories for your body’s needs, then it will start to slow down your metabolism in order to conserve energy. 

There can be many causes of low levels of the thyroid hormones T4 and T3, but if it is due to a history of eating low calorie diets, then the solution is to consistently increase your caloric intake so that your body trusts that it has enough energy coming in. Your body will then no longer need to conserve energy by slowing your metabolism. This is why at G-Plans, we put a focus on resetting your metabolism by consuming more food, which is helpful to reverse this negative effect that crash diets can have on one’s metabolism. If metabolic function is not restored, a person will continue to struggle with their weight despite other weight loss efforts. 

Other Risks of Low Calorie Diets on Thyroid Function

Another risk of eating a low calorie diet is that when doing so, you run the risk of becoming deficient in certain nutrients. There are many nutrients that are important for thyroid health, so if you aren’t eating much food, you may not be getting enough of these nutrients that are necessary for a proper functioning thyroid. Some of the nutrients needed for thyroid health include iodine, selenium, zinc, iron, and B vitamins. So if you aren’t getting enough of these nutrients, your thyroid health will suffer because your body may not be able to make enough thyroid hormones. 

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