Feedback inhibition is a mechanism that benefits cells by stopping the production of certain products when they reach a certain concentration. It works by altering the activity of enzymes, essentially flipping their on/off switches. This prevents the cell from making too much of a product, which could potentially become harmful at high levels. Additionally, it stops cells from expending energy on unnecessary chemical reactions. For example, if a cell already has enough energy available, it doesn't need to break down more glucose.