Cancer patients are recommended to follow the same healthy diet as the general public. The emphasis should be on eating plenty of fruits and vegetables, healthy fats, whole grains, and lean proteins. But side effects of treatment can make this difficult, and cooking a meal can seem daunting when cancer fatigue has left you wiped out. Staying well nourished is an important part of cancer treatment. Not eating enough will worsen fatigue, creating a vicious circle that can be hard to get out of.