My wife is also small and lost weight rapidly after surgery. She couldn't tolerate any of the recommended protein drinks because the folfirinox had altered her sense of taste and smell and just putting those products near her made her sick. We just discovered a product called Enterade which is designed to heal the digestive system and hopefully allow better absorption and nutrition. I'd suggest getting your wife on this quickly to see if you can avert further weight loss. My wife has been in treatment, chemo and surgery for 3 years and her digestive system has started to respond to the Enterade now in the 3rd week taking it 2x per day. You want her weight up before the surgery. Good luck.