3 y/o Will Only Poop While Standing in a Pull-Up
Is drinking more water a treatment for functional constipation (encopresis)?

Encopresis and Diet

Parents frequently ask if their child's encopresis (functional constipation) was caused by their diet . They also want to know if there is a particular diet that will cure their child's encopresis.

The answer to both questions is that diet alone does not cause encopresis nor is there a particular diet that will cure encopresis. However, there are certain foods that if consumed regularly can help to prevent encopresis and, in combination with laxatives and certain behavioral interventions, can help to cure encopresis.

Food which are high in both soluble and insoluble fiber are the most helpful. Dietary fiber, which includes both soluble and insoluble, is defined as indigestible carbohydrates found in plant cell walls. Some foods are higher in soluble fiber (such as oats and peas) while other foods are higher in insoluble fiber (such as vegetables and whole grain bread).

More detailed information about the amount fiber in specific foods, the daily fiber requirements for children and about different fiber supplements can be found in chapter 17 (Food and Drink for Good Poops) of my book.