1. Your Genes
Metabolism is how your body changes food into energy. If your body is slow at burning calories while you rest or sleep, you probably got that from your parents, through your genes.
2. Hormones
A shift in your hormones can put the brakes on your body’s energy use. That can make you tired. Some conditions, like an underactive or overactive thyroid and diabetes, are hormonal diseases that affect your metabolism. Stress also releases hormones that can trigger a slow-down.
