WEIGHT GAIN AFTER BYPASS

I'm 16 months post opt, 60 yrs old, lost 110 pounds and hope to lose another 30. Some people who know that I've had the operation ask about weight gain after a year or so and to tell you the truth I'm at a loss to explain why and how that happens. How, if nothing changes in your insides, can you now gain weight? I know there has to be a medical reason not just a simple answer of "eating more". Does the body start to absorb more calories?........and if so does it absorb more vitamins etc also?  thanks,  Stephanie

Hi Stephanie, There are many reasons why people gain weight after 1 year. The most common is: stretched pouch. When you are immediately post op, your pouch (for a RNY) is approximately 30 mL, or the size of a shot glass. Over time, the pouch will slowly stretch. Usually after 1 year a person can eat 1/2 sandwich, 1 piece fruit and 8 oz beverage at one time. Very different than immediately post operative. With an increased pouch size, means increased food intake. If a person is making poor eating choices - like high fat junk foods, then, he or she can re-gain his or her weight. So, that explains the simple answer of "eating more". However, some lose weight because a portion of thier intestine has been bypassed, causing malabsorbtion. This will also yield wieght loss. However, over time, your intestine will adapt and allow for more absorption of food. Your intestine that may have a 1" diameter, will increase to a 3" diameter or more over time to allow more surface area for absorption. So, if someone with WLS is banking on malabsorption for his or her weight loss, then after 1 year or so, they may see weight gain due to the body's adaption. So, yes, the body can absorb more calories over time. Vitamins, on the other hand, likely no. There are specific sites of your intestine that are responsible for vitamin absorption. So even if your intestine adapts to absorb more food, it simply can not do the job of other areas of the intestine - no matter how big it gets. However, my theory on why people gain weight after one year is a combination of the above, but more importantly, because they feel better, they know what they can and can not eat, and they've learned to eat with a bypass very well. Hope that helps. Let me know if you have any additional questions. Sara Nejat-Bina, RD eNutritionCare.com