45 minutes wait after a meal for activity allows more blood channeled to stomach resulting in better digestion.
It is no different than eating a meal and going to bed. You have a higher likelihood of food or bile spilling up into the esophagus or mouth. It was not uncommon for me to throw up a little bit if I swam right after eating. Kids eating hot dogs, chips and noodle or potatoe salad, not conducive to good digestion.
Eat dinner about 5 pm, hours before bedtime, don’t go swimming after eating a junk food fest.