If you have no idea why we’re pondering this question, go brush your teeth real quick and grab a drink (orange juice, iced tea, beer—anything except water). Awful, isn’t it?
You can thank sodium laureth sulfate, also known as sodium lauryl ether sulfate (SLES), or sodium lauryl sulfate (SLS) for ruining your drink, depending on which toothpaste you use. Both of these chemicals are surfactants—wetting agents that lower the surface tension of a liquid—that are added to toothpastes to create foam and make the paste easier to spread around your mouth. They’re also important ingredients in detergents, fabric softeners, paints, laxatives, surfboard waxes, and insecticides.
So, anything you eat or drink after you brush is going to have less sweetness and more bitterness than it normally would. Is there any end to this torture? Yes. You don’t need foam for good toothpaste, and there are plenty out there that are SLES/SLS-free. You won’t get that rabid dog look that makes oral hygiene so much fun, but your breakfast won’t be ruined either.