According to the American Association of Clinical Endocrinologists, more than 50 million Americans are affected by some type of thyroid disorder. Diet and stress are the two things that most strongly affect your thyroid function.
After you eat too much sugar, you get a large rush of sugar into the bloodstream. This forces your pancreas to release a mountain of insulin that leads to a corresponding low-blood-sugar crash shortly afterward.
Low blood sugar not only stimulates more cravings but also triggers a release of the stress hormone cortisol, whose job is to break down carbohydrates stored in the muscles to bring blood sugar levels back up to normal. Repeated cortisol releases from episodes of low blood sugar suppress the function of the pituitary gland, and without proper pituitary function, your thyroid doesn’t function properly.
Low thyroid function and excess sugar form a Catch-22: Low thyroid function slows insulin’s clearing of glucose from the blood, and high sugar levels slow thyroid output. When you’re hypothyroid, your cells aren’t very sensitive to glucose, and because your cells don’t get the glucose they need, your adrenals release cortisol to increase the amount of glucose available to them.
As long as you keep yourself on the sugar-binge-then-crash roller coaster, your thyroid won’t work properly.
Another common source of thyroid failure is Hashimoto’s thyroiditis, an autoimmune condition where the body makes antibodies against its own thyroid tissue. Studies have shown that the insulin spikes caused by high sugar intake increase the destruction of the thyroid gland in people with Hashimoto’s disease.