For decades, ads for treats sweetened with substances like Sweet’N Low, NutraSweet, and Splenda have promised what seems like a miracle of modern science: that you can enjoy all the dessert you want, calorie-free.

No need to deprive yourself—with artificial sweeteners, you can literally have your cake and eat it, too. But are these substances safe? Don’t they give cancer to rats and mess up your metabolism?

Listen in now for answers to all these questions, plus the tale of a sugar-free gumball marketing blitz, courtesy of none other than Donald Rumsfeld.