Wash hands with warm, soapy water for 20 seconds.
Wash peach, apple, celery, and grapes or berries.
Dice peach and apple (leave peels on). Dice celery. Cut grapes in half. If using berries, leave whole.
Chop nuts into small pieces.
Combine fruit, celery, nuts, and yogurt.
Toss gently and serve immediately. Serve alone or in pita bread as a sandwich.
Store leftovers in the refrigerator up to one day.