Here's some info I pulled for you that may help answer your question:
"In the early stages of your withdrawal, you might not be up for eating solid foods, so many people choose to drink Ensure protein drinks instead, as meal substitutes. A diet high in protein is essential for detoxing. Red meats, while high in protein, should be avoided during the early stages of your withdrawal, because they contain components which heighten pain and inflammation. Proteins are the building blocks for every neurotransmitter and enzyme in your body!"
"Eat foods high in fiber, which aid in the removal of toxins in your body. A diet high in fiber lowers cholesterol, too."
"And, of course, be sure to eat lots of fruits and vegetables. If you're looking for liquid nutrients, fruit and vegetable juices do the job. Be sure to select real, fresh squeezed orange juice over Sunny D or other artificial juices, which contain only a small percentage of the real thing."
"In addition to proper nutrition, a supplement regimen of amino acids, vitamins, and minerals is very important to returning your body to its normal state."
http://www.managingwithdrawals.com/index4.htm
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A ROLE FOR NUTRITION IN DRUG WITHDRAWAL PROGRAMS
http://www.neuroconcepts.memberlodge.org/resources/Documents/role%20for%20nutrition%20in%20drug%20withdrawal%20programs%20-%20part%201.pdf
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Ingredients that Help with Opiate Withdrawal
http://www.medhelp.org/tags/health_page/45/Addiction/Ingredients-that-Help-with-Opiate-Withdrawal?hp_id=593