Eat protein foods (think meats, eggs, dairy, and beans) because they're essential for repairing your body. Include carbohydrates (especially whole grains that are high in fiber) because they're necessary for energy. Also incorporate some healthy fats (such as olive oil, nuts, and seeds) to provide important nutrients and additional energy for your body.
If you decide to breastfeed your baby, plan on eating pretty much the same foods you ate while pregnant throughout the length of time you choose to nurse. Of course, you may find that you need more calories while you're nursing than you did while you were pregnant; whether you do depends on how much milk you produce.Nursing moms may lose some of their lingering pregnancy pounds fairly quickly due to their bodies' increased calorie needs and ability to use stored fat as energy to produce milk.
If you're breastfeeding, drink plenty of fluids, get rest, and continue to take your prenatal vitamin because you can use the extra vitamins and minerals while nursing.