Stress activates your glucose metabolism, leading to an increase in the hormone cortisol secreted by the adrenal glands. Cortisol, the stress hormone, can cause your blood sugar levels to rise. Dopamine and serotonin, known as happiness hormones, decrease. These hormones are normally in balance and help maintain your good mood. In a state of stress, the balance between sleep, hunger and satiety metabolism is disrupted, and this may lead to an increase in appetite or loss of appetite.