Dietary no-no is a term used to describe food items that are not recommended for consumption due to their high FAT content. The three letter solution for this term is FAT, which stands for fatty acids. Fatty acids are molecules that contain long chains of carbon and hydrogen atoms and are found in many foods. Eating too much of these fatty acids can lead to health problems such as obesity, heart disease, and diabetes. Therefore, it is important to limit the amount of fatty acids in one's diet in order to maintain a healthy lifestyle.