Side Effects

Certain side effects are seen with all bariatric surgeries simply because so much weight is lost in a short period. These side effects are also seen in people who've lost weight without surgery.

  • Transient Hair Loss

Almost every gastric bypass, BPD and some sleeve gastrectomy patients suffer hair loss and hair thinning during the first six months. Hair loss is alarming, however it typically will not lead to baldness and it is reversible. Once your weight stabilizes and you consume more protein, the hair will grow back. Hair treatments and permanents should be avoided.

  • Nausea/Dumping Syndrome

Since your new stomach pouch is quite small, you will not be able to eat as much food as you once did. Therefore, if you get full but continue to eat, or eat quickly without chewing thoroughly, pain and vomiting are likely. These habits will likely change after several episodes of vomiting. You will have to re-learn to eat by eating slower, chewing food thoroughly, and stop eating when you feel full. Overeating or consuming concentrated sweets or carbohydrates can lead to nausea and dumping syndrome, in which the contents of the stomach quickly enter the small intestines, causing profuse sweating, nausea, dizziness, palpitations and weakness.

If you have had no problems dining during the first month after surgery and then suddenly experience nausea or vomiting after eating or drinking, you may have developed a stricture, or narrowing, at the point where the stomach pouch connects with the small intestine. This can be serious, so call your surgeon for further evaluation.

  • Nutritional deficiencies

Nutritional deficiencies can arise, particularly in patients who have a gastric bypass or BPD/DS, which causes food to skip the duodenum (the section of the small intestine where most iron and calcium are absorbed). Left uncorrected, this can lead to anemia or osteoporosis, among other conditions. Patients with a biliopancreatic diversion, which by design dramatically reduces nutrient absorption, have to take even greater care to avoid nutritional deficiencies. The good news is these problems can be avoided by eating the right foods in small amounts, taking regular vitamin and mineral supplements, and getting regular medical checkups which include blood testing.

  • Lactose Intolerance

After certain bariatric surgeries, lactase, the enzyme needed to digest milk and other dairy products, does not reach food in the usual fashion. Consequently, you may become lactose intolerant, leading to gas, cramping, and diarrhea. This can be resolved by avoiding dairy products and switching to alternatives like soy milk, rice milk, or a lactose-free milk like Lactaid.

  • Changed Bowel Habits

Weight loss surgery can change your digestion as well as your food intake. Some patients experience constipation, which can be treated with a mild natural stool softener, or by simply increasing drinking more fluids. After a biliopancreatic diversion (BPD)/duodenal switch (DS), patients may experience diarrhea. This is usually caused by having too much fat in the diet. If not, a small amount of pancreatic enzymes may be required, which would be prescribed by your surgeon.

  • Loss of Muscle Mass

You may lose muscle mass after surgery. Since you're consuming far fewer calories, and less protein, your body will look to burn other energy stores to maintain itself. Surprisingly, the body prefers to use protein-rich muscle for energy before it taps into fat. Therefore, your initial weight loss may come at the expense of muscle. This is most common after a gastric bypass, sleeve gastrectomy or BPD/DS. Fortunately, this can be avoided by exercising every day and consuming more protein. Both regular aerobic activity and weightlifting is highly recommended. These activities can be alternated, but should be done at least 3 times a week for 20 to 30 minutes at a time. Daily exercise, however, is ideal and should be the goal. Regular exercise increases fat burning, builds and tones muscle, and raises your energy level, leading to a more healthy fulfilling life.

  • Gallstones

With any rapid weight-loss, there is an increased risk of developing gallstones. About one in ten people who undergo bariatric surgery will need to have their gallbladders removed. At NYU, we do not routinely remove gallbladders at the time of weight-loss surgery, because that would mean most people would have their gallbladders removed unnecessarily. Instead, anyone who has a gallbladder undergoing gastric bypass or BPD/DS is placed on a medication called Actigall® (ursodeoxycholine) for six months, which prevents formation of gallstones. If the gallbladder still needs to be removed, it can be done laparoscopically at a later date.

  • Excess Skin

After losing a large amount of weight, you may find yourself with excess skin in all sorts of places. This can be removed with plastic surgery. It's advisable to wait 18 to 24 months, after you lose most of your excess weight and your body begins to equilibrate. Should plastic surgery be necessary, be sure to choose a surgeon with experience in this area. We are happy to make recommendations. It should be noted that this is considered cosmetic surgery and thus may not be covered by insurance. However, there are many plastic surgeons who can offer flexible payment terms.

  • Pregnancy Problems

Little is known about pregnancy after weight-loss surgery. Although women have successfully carried pregnancies to term as early as six months after bariatric surgery, their babies have tended to be underweight. Other patients have had miscarriages if they became pregnant shortly after surgery. Because of these uncertainties, we suggest that you wait for at least 18 months after surgery to have a child. And even after that, make sure that your obstetrician is aware of that you've had weight-loss surgery. You and your baby should be followed closely.
If you have a gastric band, you may need to have a band adjustment, allowing you to take in enough nutrition during pregnancy. After delivery, the band can be tightened accordingly. Most importantly, we recommend that you come in to see us if or when you become pregnant so that we can discuss any impact your bariatric surgery has on your pregnancy.