Of all the small routines worth keeping, the after-dinner walk might be the easiest to like. It asks for very little: shoes, a door, and ten or fifteen minutes you were probably going to spend on the couch anyway. This letter is about that walk, framed not as exercise but as a calm way to close the day.
The appeal is partly that it sits naturally at the end of a meal, which makes it easy to remember. You finish dinner, you step outside, you come back. Habits that attach themselves to something you already do tend to stick, and dinner happens every evening whether you planned a walk or not.
Keep it gentle on purpose. This is not a brisk fitness walk with a target; it is a stroll. Around the block, down the street and back, a loop of the garden if that is what you have. The point is movement and a change of scene, not effort. Treating it as effort is the surest way to start dreading it.
There is a pleasant side benefit that has nothing to do with the gut: a short walk after dinner is a good seam between the busy part of the day and the quiet part. The light is often nice. Your head clears a little. By the time you are home, the evening feels like it has properly begun.
As with everything in these letters, missing it is fine. Rain happens, tiredness happens, some evenings you simply will not go. The walk is not a streak to protect. It is just there, an easy thing to return to tomorrow, asking nothing more than that you step outside when you feel like it.