Dr. Jau-Fei Chen advocates the concept of Nutritional Immunology in response to the need to take care of the body by feeding it the whole-food nutrients. When the body is properly nourished, it can defend itself against numerous attacks from bacteria, viruses and germs.

Experts have concluded that the foods which are beneficial to human health must fulfill the following six criteria:
1. Plant food
2. Healthy plant
3. Wholesome plant
4. Rich in phytochemical
5. Many varieties and sufficient quantities
6. Does not interfere with the body's repair ability and defenses of diseases.

There are four things to do to maintain good health.
1. Maintain stable emotions
2. Regular exercise
3. Ensure sufficient sleep and rest.
4. Take balanced nutrition

The first three items are fairly straightforward and easy to maintain, but the fourth item requires wisdom and knowledge to discern which foods are most valuable for the body.