A lot of my runs happen first thing in the morning, and to be honest, I’m not usually brushing my teeth beforehand. Repugnant, I know; just let me be. But I’m half-awake, and my only real goal is to get out the door before the excuses start happening. I’ll clean my teeth when I’m back, and that’s always been the deal.

So I run, I come home, and then I do the normal stuff. Shower. Coffee. Brush my teeth. Which, it turns out, is accidentally sort of the correct order—especially if you’re a gel person.

Runner Katy Laser posted a TikTok after a dentist visit where she got asked the classic question tied to the potential cause of cavities: Do you drink a lot of soda or sparkling water? She said no. Then she mentioned running gels. According to her, the dentist immediately clocked it. Gels are sugar; they’re sticky, your mouth gets dry when you run, and a lot of fuel is acidic.…