I would advise you to check out Dr. Garth Davis and his book Proteinaholic. He is a bariatric surgeon who found many of his bypass patients were coming back to him gaining weight. After much research he wrote this book and has become a vegan himself.

It should be at least 70% cocoa and preferably organic. My favorite is Theo's but there are lots of good organic brands.

If she's 6 days post-op, it might be part of the post-op clear diet. 

I had to lose 5% of my current weight so about 10.5 lbs.  I went on their diet immediately even though I had a little more than a month before my surgery.  I was told to keep my carbs to under 30 grams per day and about 80 or more grams of protein.  It's important to keep track of the carbs because most things have carbs in them.  I had to cut out everything "white".  Bread, pasta, desserts, chips, etc.  I thought it would be hard to do but actually once I started I was so motivated for the surgery that I didn't even crave the things I loved.  I had a protein shake in the morning, 2 hard eggs and 1/2 cup low sugar, low carb cottage cheese for lunch and a protein meat for dinner with a veggie.  I'd look for the lowest carb possible.  I stayed away from fruits and fruit juices as they have too many carbs.  In the evening however, if I still had carbs and wanted a treat, I'd have sliced strawberries.....always weighed them out first.  I was able to lose 21 lb. before my surgery.  I am 1 week out today and have lost 5 more.

Good luck to you.

Congratulations to you!!  I just had my surgery February 20, 2017 and need to hear success stories like yours.  Keep it up and I am looking forward to my weight loss as well.'