Stress and Obesity are linked to each other. When people are stressed out they have more tendency to food items that are more in Fat and Sugar. Serotonin, Cortisol and Neuropeptide are few hormones that are the reason behind this.
Crave for eating fatty and sugary food at the time you are stressful will make you body feel good. This feel good is actually produced by the serotonin hormone in the body. The consumption of fatty and sugary food items will make one obese.
The other hormone Cortisol actually works as a fat storage and energy use. It is known for making you hungry. This is a reason for people to eat more of fatty and sugary food.