How am I losing weight after gastric bypass surgery?

Since my gastric bypass surgery, I have been slowly but surely losing weight.  The question is, how am I losing weight?  Why am I losing now when all of my previous weight loss attempts have been futile?  What is the major difference after weight loss surgery?  I decided to do a little research to find out more and share my experiences with you.  Keep in mind I am currently only 4 months out from surgery and have only lost a fraction of the weight that I need to.  Here is what I’ve learned so far.

Eating after surgery

Some of the differences before and after surgery are obvious, but some are more subtle.  The physical changes with gastric bypass surgery involve cutting your stomach down to a fraction of its original size.  Your new stomach is so small, that after surgery they refer to it as your “pouch”.  Obviously, the result is that you can only eat tiny portions of food at one time.  I expected that I would need to eat many times per day to make up for this, but that is not the case.  What I didn’t realize is that your perception of hunger also changes dramatically after surgery.

I no longer experience hunger the way that I used to.  Right after surgery, I really didn’t feel hungry at all.  If I didn’t eat all day, I would likely still feel light-headed or tired.  But I did not get hunger “pains” anymore in my stomach.  Now that I am over 4 months out, I will occasionally feel hungry, but not nearly to the extent that I used to.  I don’t ever experience that “I’m starving” feeling.  This allows me to eat much less food overall without feeling poorly.  This is the most obvious mechanism of my weight loss.

In addition to eating much smaller portions of food, I find myself eating healthier foods.  I do not tolerate unhealthy foods the way I used to.  In fact, there were times when I basically lived on junk foods.  Now, eating junk food makes me feel unwell, even when I eat small amounts.  Especially when I eat sugar, I find my heart starts to race, making me feel panicky.  I also get abdominal cramping.  These feelings can last for a while, which is a big deterrent in eating junk food.  I also don’t digest “filler foods” as well as I used to – bread, rice, pasta – so I tend to steer away from these.  I have been forced to eat more whole foods and do more cooking, which I think is always a good thing!

Hormones after surgery

There has been quite a bit of research into how gastric bypass surgery changes your hormonal processes as well.  The gut hormones that reduce hunger and make you feel satisfied tend to be increased after surgery.  Leptin is a hormone that is usually higher in obese people, and levels have been found to be decreased immediately after surgery.  This occurs even before the weight loss.  Another hormone, ghrelin, is an appetite stimulant.  This is also found to be decreased after surgery.  Many of these hormone changes occur even before you start to lose weight.  This means that the surgery itself must cause some of these hormonal changes. (Beckman et al 2010)

Even with a modest weight loss of 50 lbs (about 1/3 of my goal), I have already seen my blood sugars and cholesterol normalize.  In addition to losing weight, my body is now healthier than before surgery.  I no longer require medication to control my blood pressure, blood sugars, or my acid reflux (a pleasant surprise).  These changes happened much faster than I expected, which is a great benefit of the surgery.  I was able to stop my blood sugar and blood pressure medications immediately after surgery, and my acid reflux medicine about 3 months after surgery.

One of the ways that you may lost weight after surgery is that you don’t absorb nutrients in the same way that you used to.  During surgery, the first part of your intestine is bypassed, and this is where much of the absorption used to happen.  Food no longer passes through this portion of the intestine, so less nutrients (and calories) are absorbed.  The down side is that you don’t absorb as many of the vitamins and minerals that you need either.  I will have to take several supplements for the rest of my life to counteract this.  Currently, I take two multivitamins w/ iron daily, Calcium and Vitamin D twice daily, and Vitamin B complex weekly.  

Exercise after surgery

I have also found that weight loss begets more weight loss.  I don’t necessarily feel like I have more energy, as I am eating much less than before.  But losing weight makes it easier to exercise and less stressful on my body and joints. This makes me more likely to exercise regularly.  Of course, I was still very out of shape, so I have had to start slow with the exercise.  I started with fast walking and hope to progress to jogging soon.  I am also excited to get back to yoga, which I’ve found is harder to do when you are overweight.  It is just so much harder to move your body when you are overweight or obese.

All of these things have contributed to my weight loss.  Before surgery, it’s often hard to believe that you will lose weight at all because you have been so unsuccessful in the past.  It’s even harder to understand how this weight loss will happen.  Even though I tried to educate myself before surgery, there were still many things about surgery that I was not prepared for.  Please let me know if you have questions about weight loss surgery, I’m always happy to share!  And for those of you already on the journey, what things were you surprised about after surgery?  Please share in the comments!

Beckman, L. M., Beckman, T. R., & Earthman, C. P. (2010). Changes in gastrointestinal hormones and leptin after Roux-en-Y gastric bypass procedure: a review. Journal of the American Dietetic Association, 110(4), 571–584. https://doi.org/10.1016/j.jada.2009.12.023