Expert: Jacqueline Jacques, ND - 11/10/2008

Question
I am about 16 months post lap-rny and I was wondering how much fat is absorbed.  I had a 110 cm bypass and I've been told as much as 30 percent of the fat that I consume is not absorbed.  I do have very foul smelling stools which seems to confirm that I'm malabsorbing a significant amount of fat, but I was just curious if you know how to figure out how much one might be absorbing or not.  I'm at my goal weight and trying to maintain and I'm just trying to fine-tune my dietary intake for optimum long-term success.
Thank you!

Answer
Dear June,

With the length of your bypass, you likely have some fat malabsorption, but I do not think anyone could say definitively how much.

You really can't tell how much fat you are malabsorbing without some pretty sophisticated testing.  The standard method uses a fecal fat analysis done from a 5-day collection and a lipid tolerance test, sometimes using a radiolabeled fat.  A gastroenterologist would generally order and conduct these tests.

There are also other causes of foul stool odor after malabsorptive weight loss surgery that have nothing to do with fat malabsorption.  Other potential problems would be bacterial overgrowth in the intestine and food intake patterns.  

So my first suggestion would be to return to your surgeon's office.  If you need further testing done with a gastroenterologist he can order that for you - or he may suggest that you meet with the dietitian or try an over-the-counter medication like Devrom.

In Health,

Dr. Jacques