Inserting bread upside down into a toaster can potentially help toast the bread more evenly, but the difference might be marginal and depend on the type of toaster you are using. Here's why some people suggest toasting bread upside down:
Heat Concentration: In some toasters, the heating elements are closer to the top than the bottom. By placing the bread upside down, the heat is directed to the softer, more porous side of the bread, which can help it toast more evenly.
Moisture Evaporation: Bread's moisture content can affect how evenly it toasts. Placing the bread upside down allows the moisture to escape from the softer side of the bread, reducing the chances of it becoming too soggy during toasting.
Prevents Over-Browning: Toasters typically toast one side of the bread more than the other. By placing the bread upside down, you can prevent the side that's usually more exposed to the heat from becoming overly browned or burnt.
However, not all toasters have significant differences in heat distribution between the top and bottom. Many modern toasters are designed to toast bread evenly on both sides, regardless of which way you insert it. Additionally, toasting preferences can vary from person to person, with some people liking their toast more well-done on one side than the other.
Ultimately, if you find that toasting your bread upside down in your toaster leads to more even results, you can continue doing so. But if your toaster toasts the bread evenly regardless of its orientation, then it may not make much of a difference. As with any kitchen appliance, it's a good idea to experiment and see what works best for you and your specific toaster.