Prednisone has a tendency to raise the level of glucose, or sugar, in the blood, which can cause increased body fat or diabetes in some people. It is important to avoid "simple" carbohydrates and concentrated sweets, such as cakes, pies, cookies, jams, honey, chips, bread, candy and other highly processed foods. If you are on steroids for a medical reason, you can increase the protein content of your food daily.