Why am i always hungry?

It's your metabolism. I have a close friend who is really really skinny and could eat a horse entirely in about 5 minutes. Depending on your age and growth, your metabolism is quite fast through your teenage years and will really start slowing down once you become an adult. Many obese people were quite skinny at one time, they just had a quick metabolism in their younger years, and once they got older their metabolism slowed, but they still couldn't stop the diet and nutrition habit they had when they were younger, which in turn, made them fat.