If you do fast for fitness reasons vice spiritual, I would suggest an all fruit and veggie fast. It would be like this:
meal 1: Eat a bowl of fruits (i.e.: pineapple, apple, strawberry, melon(s), grapes, etc.)
meal 2: Green salad (med.) use apple cider vinegar and Safflower oil for dressing (2tbl spn each)
meal 3: Bowl of fruit
meal 4: Green salad
meal 5: Bowl of fruit
Your supplements can be Amino acids, Colostrum, Multi-vitamin, EFA-CLA complex pill.
During your workout drink Apple Cider vinegar mixed with L-Carnitine and water (you'll reek but who cares)
This is good for fitness as it cleans your colon and stomach of rotten meat, and it fills your body with antioxitdants, AND it's a great way to lose fat while maintaining muscle and energy.