While there are many symptoms that are associated with hypothyroidism, there are 3 that tend to be most concerning for my patients: fatigue, brain fog, and weight loss. This is the type of weight loss wherein patients have tried many restrictive diets and rigorous exercise without sustainable success. In this blog, I explain why weight loss is connected to thyroid function.

The thyroid gland sets the resting metabolic rate (RMR) of the body. RMR is a measurement of how fast your body can metabolize key nutrients in order to sustain life without daily activity and caloric intake in the form of food. In other words, the thyroid gland sets the metabolic tone of the body.

When thyroid gland is underfunctioning (as in cases of hypothyroidism), your body loses metabolic tone and does not metabolize key nutrients as efficiently. This creates a cascade of metabolic dysregulation that may lead to sugar (aka glucose) and cholesterol issues – but more on that another time.

In hypothyroidism, your body always ends up in a caloric excess even with restrictive diets and rigorous exercise because of low RMR. Daily caloric excess over time leads to weight gain that is difficult to lose unless RMR increases with successful treatment of hypothyroidism.

In hyperthyroidism, your body always ends up in a caloric deficiency even with restrictive diets and rigorous exercise because of high RMR. Daily caloric deficiency over time leads to weight lose that is difficult to gain unless RMR decrease with successful treatment of hyperthyroidism.

There are cases of hypothyroidism where the patient does not struggle weight loss. In some of these cases, they may actually struggle from difficulty gaining weight. I bring this up because weight alone is not the only clinical indicator of thyroid function. Other symptoms present will guide the working diagnosis and lab findings will often lead you to the final diagnosis. In many of these cases, patients exhibit symptoms of both hypothyroidism and hyperthyroidism wherein I find it important to assess for autoimmunity and check for thyroid antibodies.