Need for defecation after having a meal is due to gastrocolonic reflex (this is typical for kids, when food passes from the stomach into the upper part of the small intestine, triggers increased contractions of large bowels)
When there is a obvious or overactive gastrocolic reflex in adults, the explanation usually is irritable bowel syndrome.
Actually, people with IBS have hypersensitive gastrointestinal tract, and the very lower end of the colon contracts severely only fifteen minutes after a meal has been eaten. This gives a explanation how an IBS attack can hit so fast and so hard after or even while eating, resulting in loosy stools.
In some patients with IBS this reflex is almost deminished and the colon contracts very slowly, and they suffer from constipation.
Stress being not home surely adds to this problem, since IBS sufferers are very vulnerable to stress.