Question:
What degree of malabsorption can be expected with a proximal RNY?

I read on here once that proximal RNYs experience a 30% malabsorption rate. I was surprised to see such a high number as I had always considered the small amount of intestine bypassed with the proximal to deem the malabsorptive side of the surgery insignificant. If we are looking at 30% of the food passing undigested, does that mean if I am eating 900 calories a day that only 600 are being absorbed? Likewise that would mean I should up my protein and vitamin intake by 30% so as I abosrb the correct amounts right?    — Rita O. (posted on April 29, 2000)

April 28, 2000
Yes they say there is about a thiry percent malabsorbtion. This varies on exactly how proximal the bypass is. It is very important to realize that diferent nutrients get absorbed at different levels along your intestine. Calcium, Iron, B12 and folic acid are almost completely absorbed in the first two or three feet (the amount bypassed). Vitamin supplements are essential post-op and for life. As far as protein goes, this is the key to you weight loss and well being. Aim for a minimum of 1.3 grams of protein for every kilogram (2.2lbs) of ideal body weight. Add more if you are severely obese (My goal is over 150 grams per day). "Living a Lighter You" by Dr Gaye Andrews, PhD gives you a really good guide to nutrition post procedure. Good luck, Mark
   — Mark R.

April 29, 2000
The question should be "30% of what?" because all food is not created equal when it comes to digestion. I've got a very distal bypass (DS) and my surgeon told me that I absorb all of the simple carbs I eat (fruits, most veggies), most of the complex carbs (whole grains, etc..) only 70% of the protein, and much, much less of the fat. So it follows that, for me, 900 calories a day composed mostly of carbs will be almost completely absorbed, but the same calories composed primarily of protein and fat will have a very low absorbtion rate. Again, my bypass is distal, but the concept remains the same. Rates of absorption will vary by content.
   — Duffy H.

April 29, 2000
I would request a copy of your operative report and find out exactly how much intestine was bypassed. That should give you a good idea of what your malabsorbtion is.
   — Kim H.