Found on RunnersWorld.com and written by Jenny Hadfield
You can start by watching what you eat before a run.
Few things are worse than getting a side stitch during a run. Here are three ways to prevent the problem, and one strategy for stopping a stitch in its tracks:
Eat mindfully pre-run. There are many theories as to why stitches occur, and one of them factors in what and when you eat pre-run. Foods that are higher in fat and fiber take longer to digest. That doesn’t mean they are bad foods, but if you eat them within one to two hours before a run, they can cause havoc—creating stomach upset, stitches, and other problems. Experiment with a variety of foods pre-run, eat lightly, and give yourself plenty of time to digest. One person’s perfect pre-run fuel is another’s disaster.
Invest in a solid warmup. Going from sitting to running speed may save you time on the watch, but it can create irregular, rapid-fire breathing patterns, which can translate to you bending over in pain on the side of the road (with a side stitch). Invest in two to three minutes of brisk walking, gradually work into an easy running effort, and then into your planned running workout pace. Doing so will increase the quality of your workout and decrease the risk of stitches that arise from pushing the throttle too soon.
Regulate your breathing. Run like a swimmer—with efficient breathing patterns that are in sync with your body. Swimmers can only breathe when their faces are out of the water (obviously), so they focus much of their time learning their breathing tempo and matching it to the rhythm of their stroke. Runners can benefit from the same technique by matching their breathing to their strides—inhaling for two to four strides and exhaling for the same. The faster the pace, the shorter the sequence (fast pace = one or two strides per breath, slower = three or four strides per breath). This can not only prevent stitches, but also improve the efficiency of your oxygen transport. Plus, it’s a great way to keep in touch with your running effort levels without a watch.
Slow down and exhale to release the stitch. If you still get another side stitch, implement this strategy and it will go away in seconds (I promise). Slow your pace and exhale as the foot on the opposite side of the stitch strikes the ground. This doesn’t mean every time that foot hits the ground, but as you exhale, do so in sync with that opposite side. When you exhale, you use the muscles of your diaphragm. When this happens in unison with your foot striking the ground, the impact forces travel up the body and through your core (your side too) and exacerbate (piss off) the muscles in spasm creating that stitch. When you change the side of the landing forces to the opposite side, the tension causing the stitch releases. For example, your stitch is in your right side. You slow your pace, and exhale as your left foot is hitting the ground. Voila! Side stitch is history and you’re running without swearing once again :).