Fall is the time of drying and contraction, so we may choose and prepare food accordingly.  We also want to aim for fresh and seasonal, which means pumpkin bisque!
One guideline is to concentrate energy and flavor: baking, sautés, and liquid reductions.  Emphasize sour foods: sourdoughs, cheese and yogurt, aduki beans, citrus, vinegar-based foods like sauerkrauts and pickles.
To help balance dryness, include energetically-moistening foods: organic soybean products, spinach, millet, apples and pears, seaweeds, mushrooms, almonds, honey, organic dairy, and generally less salt.  Moderate these foods when damp conditions are present, like mucus and obesity.
Additional foods that support the Metal Element include rice, navy beans, onions, cabbage, root vegetables, cauliflower, cod, beef, and turkey.  Note that many of these are seasonal.
For deeper and more personal guidance in seasonal nutrition, consult an acupuncturist or Traditional Chinese Medicine practitioner.   My Fall Special  Into the Darkness! also features Autumn Nutrition Tao.

Pritchard, Paul.  Healing with Whole Foods, 3rd Ed. 2002.
Reid, Daniel.  Chinese Healing and Health. 1994.