Look for excesses in habits like nicotine, drugs, clenching or grinding of teeth. Other habits like nail or hairpin biting, neck or jaw habits contribute to imbalance and disharmony.
The key is balance. A diet rich in natural foods, in as close to a natural state as possible, is physically the most rewarding. For an in-depth view at the deeper meaning of nutrition read the "Yoga of Nutrition" by Mikhael Aivanhov.