Eating a healthy diet and maintaining physical exercise are both important. If you eat too much, you should avoid physical exercise. Otherwise, muscles and digestive system compete for nutrients, causing upset stomach, cramping and diarrhea. After finishing workout, be sure to eat something. You muscles need to recover and to replace their glycogen.
However, when you are hungry, you should also avoid physical exercise, because low blood sugar levels can make you feel weak, faint or tired. Every morning, blood sugar level may be low. If you do not eat a breakfast, and start physical exercise, you may feel uncomfortable.