What does it mean if u have to poop right after u eat it been happening for the pass 3 days?

Gastrocolic reflex: It is normal to have a bowel movement after eating food. The nervous system has a reflex that as the stomach distended with new food it cause the colon to also contract to cause a bowel movement

Normal.: This is a pretty normal thing - it's called the 'gastrocolic' reflex. Your gut motility increases when your stomach stretches - essentially making room for the next batch of food to come through! If your stools are changing in other ways, like having blood or mucus, alternating diarrhea/constipation, or abdominal pain, please see your doctor.