If a pregnant woman has been diagnosed with gestational diabetes during pregnancy, it is still necessary to decide what food to eat based on the specific blood sugar levels. If the current blood sugar level is relatively stable, she can follow a diabetic diet, eat smaller meals more frequently, and consume more fresh fruits and vegetables. It's important to avoid foods that cause high blood sugar, and it is essential to walk or engage in appropriate exercise 30 minutes after eating to help metabolize the blood sugar. However, if the blood sugar remains high and does not decrease significantly, insulin might be needed to lower the blood sugar levels.