Where is the thyroid? Whys is the relationship between metabolism and the thyroid?

The thyroid sits low on the front of the neck. Your Thyroid lies below your Adam's apple, along the front of the windpipe. Thyroid hormones control metabolism, growth, body temperature, muscle strength, appetite, and the health of your heart, brain, kidneys, and reproductive system.

The thyroid’s main role in the endocrine system is to regulate your metabolism, which is your body’s ability to break down food and convert it to energy. Food essentially fuels our bodies, and our bodies each "burn" that fuel at different rates. This is why you often hear about some people having "fast" metabolism and others having "slow" metabolism.