For many women, breastfeeding the baby may help to lose post-pregnancy weight.  The more a mother breast-feeds, the less weight she retains six months after birth; however, total pounds lost depends on whether a woman was overweight before pregnancy, how much she gained while expecting, and the duration breastfeeding.  Since you were overweight before your pregnancy and you’ve already gained enough weight by month 7, you should start to watch your weight right now.  Aim for 1800 calories a day from 4 cups of fruits and vegetables, 3 cups of fat-free milk, 6 ounces of protein-rich foods, 6 servings of grains, and 5 teaspoons of oil for cooking.  Discuss your diet for pregnancy and breastfeeding with your doctor.