Stress can result in the release of hormones in the body that make us more emotional and cause a rise in insulin, which signals your body to take in more sugar. We then start to crave a chocolate bar. Sweets can cause a rise in certain chemicals in the brain that create a sense of calm, and this feeling can be enough for you to become addicted to the good feelings so a habit forms. We learn that having a treat results in good feelings and so we are rewarded for eating the cake or chocolate.