I have a client that had an RNY 7 months ago, for those that don't know it's also called gastric bypass or weight loss surgery. She is making excellent progress in the gym (I am a Crossfit Trainer) but she would like to start the zone. I told her to ask her doctor if that would be condusive to her surgery. While I am waiting on the answer I was hoping maybe someone on here had any similar experiences that they might be able to help me out with. Has anyone trained a RNY patient and gotten them on the zone diet? How would the blocks work since she can only eat about 1/2 to 3/4 C of food per meal. Any help would be much appreciated. Oh she is a 260# Female, 25 YO. She is coming down from 352# and continues to lose at a faster than normal pace.

Roux-en-Y gastric bypass creates a malabsorbtion syndrome as well as mechanical inhibition to ingest large volumes of food. The malabsorbtion can make them susceptible to vitamin and nutrient deficiencies. Iron, Vit B12, Vit D, etc. She should be taking supplements. I think the Zone method of nutrition is ideal for these people. I wouldn't tell her to skip the vitamin supplements. The Zone to me is just a very healthy way of eating. I don't know what kind of counseling she received from a nutritionist (this is usually part of any person undergoing these procedures), but I can't see any reason why they or her doctor would disapprove.
Congrats on helping her with Crossfit (my brother is a Crossfit trainer also) and she needs to continue the healthy fitness and nutritional way of life. These people can and do revert back to gaining weight over time. Hopefully she can change her lifestyle.
As far as calculating blocks, that just isn't my thing. I just know the general idea and adjust eating accordingly, but I don't have the personality to sweat over a block of this or that so I can't help you there.