Possibly the only thing worse than getting that urge — the one that has you clutching at your stomach and running for the bathroom at an inopportune time — is when that urge hasn't come knocking for days, and you feel like your gut is a tight, uncomfortable coil that won't unwind. Since modifications to what and when you eat can affect your bowel movements, it's natural to be nervous that a new eating routine could also mean a new bathroom routine.