Potential Side Effects Management

Gastric surgery seems to offer the best chance for maintaining weight loss, reducing risk of disease associated with morbid obesity, and reduction or elimination of medication used for serious medical conditions such as hypertension or diabetes. Potential side effects may occur with Roux-en-Y gastric bypass (RYGBP) surgery. Listed below are known side effects and ways to help manage them.

Dumping Syndrome

The stomach normally serves as a reservoir. Following RYGB surgery, food may enter the small intestine more rapidly and in larger amounts than normal, exceeding the intestines’ ability to digest and absorb it. As a result, “dumping syndrome” may occur. There may be abdominal cramping, nausea, and/or diarrhea, especially following ingestion of foods with a high sugar content or lactose (the natural sugar found in milk and milk products). If sugar is absorbed rapidly, blood sugar rises quickly. The body then produces insulin and, as a result, blood sugar levels may quickly fall, leading to shakiness, lightheadedness, rapid heart beat, and sweating. However, these problems tend to diminish with time and with a few changes in diet, comfort with eating improves.

  • Food should be eaten slowly and chewed thoroughly.
  • Avoid foods with a high sugar content.
  • Wait 30 to 45 minutes after eating to consume liquids.
  • Include a small amount of fat with meals. Fat helps slow down the rate of stomach emptying as well as the fiber pectin found in fruits and vegetables.
  • If milk is a problem, use lactose-free products.


  • Behavioral: Patients struggle to accommodate themselves to the restrictive nature of their food intake. Some persist in eating food that they cannot tolerate.
  • Stenosis: Vomiting of recently ingested food. Excessive weight loss.
  • Protein depletion: Leads to edema at the anastomosis.
  • Marginal Ulcer: Pain, anemia, bleeding.
  • Post nasal drip: Morning vomit of thick mucus swallowed during sleep that clogs the pouch outlet. Most common during spring and fall allergy seasons. Decongestants and antihistamines seem helpful.
  • Bezoars: Improperly chewed food. Pills not properly crushed etc.
  • Gallstones: Upper abdominal pain radiating to right side and back.


  • Consuming foods with high sugar or fat content.
  • Eating or drinking too much or too fast.
  • Lactose intolerance. Eating too much dairy products.


Constipation is one of the most frequent complaints after gastric bypass. Most people experience changes in bowel habits after surgery, and will not have a bowel movement every day. Having a BM every 2-3 days is normal, as long as it is soft and passes easily.

Symptoms of constipation can include hard stools, straining to have a bowel movement, or going four or more days without a bowel movement accompanied by a feeling of fullness and bloating. It can be caused initially by the bowel slowing effects of pain medication and long term due to the dramatic decrease in the amount of food being eaten each day. To decrease chronic constipation fluid and fiber are the keys. Fluid intake of 64 ounces (8 glasses) a day is necessary to keep bowel movements soft. Fiber helps provide bulk to form stool and also holds moisture in stool to keep it soft. Easy ways of adding fiber is through chewable fiber wafers such as Beni-fiber and Metamucil. Natural fiber sources include beans, bran cereals, vegetables and fruits.

Acute episodes of constipation should be treated with a gentle agent such as Milk of Magnesia. Strong stimulants such as Ex-Lax, magnesium citrate and phosphosodas are too strong, and can cause cramping and abdominal pain. If Milk of Magnesia does not work, Dulcolax suppositories or Fleets Enemas are safer and will cause less cramping.

Contact the office if your constipation is not relieved with the above measures, if you stop passing gas, or if your abdomen becomes bloated and painful. On rare occasions further testing is needed to rule out intestinal obstructions.

Mineral and Vitamin Deficiencies

Iron, B12, folic acid, Vitamin D, and calcium deficiencies may occur following RYGBP surgery and must be monitored. Deficiencies in Vitamins A, C, K, and thiamin have also been observed as well as the mineral zinc. Electrolyte imbalance (sodium, potassium, and chloride) may or may not be significant.


  1. Persistent vomiting* – Possible causes: Lack of zinc, electrolyte imbalance, vitamin deficiency, malnutrition and/or dehydration
  2. Temporary hair loss: Possible causes: Severe calorie restriction, lack of protein and/or essential fatty acids in diet, shock of surgery, rapid weight loss, zinc or biotin deficiency.
  3. Fatigue :Possible causes: Lack of B vitamins, magnesium, iron, body adapting to using fat for an energy source instead of glucose
  4. Anemia :Possible causes: Inadequate intake of protein, B12, iron, and/or folate
  5. Nails (chipped or weak) :Possible causes: Lack of protein, iron, folic acid, selenium, zinc, biotin, Vitamins C, E, B12, and/or B6.

If these conditions persist and are severe, report them to the surgeon as soon as possible for prompt and appropriate treatment.


Take your multivitamin/mineral supplement (2) daily along with calcium (1200 mg), B12 (500 mcg sublingually (let dissolve under the tongue, nasal gel, or intramuscular injections monthly) and 325 mg ferrous sulfate (only for menstruating women).
Drink at least 6 to 8 cups of fluid daily, preferably water to prevent dehydration and maintain electrolyte balance.
Chamomile or peppermint tea can help reduce nausea.
Make sure you consume adequate protein daily. Women: 45 grams Men: 60 grams
Eat a balanced diet. Consume protein, a fruit or vegetable, and a starch/whole grain at each meal. Each food group contributes to a healthy diet.
Consume two teaspoons of margarine, mayonnaise, vegetable oil, or salad dressing that has one of the following food sources everyday: corn, safflower, sunflower, soy, granola, tuna, salmon, or sardines. Needed as source of essential fatty acids.

Taste Changes/Food Aversions

Taste changes may occur after RYGB surgery. Sweet foods are perceived as being too sweet and foods may taste spicier. Some patients report having an increased sense of smell during the first 6 to 9 months. Aversions to meats may be associated with nausea, vomiting, and/or changes in taste of meat (metallic taste). Mechanical factors, such as chewing fatigue, may contribute to aversion of meat. Difficulty in digestion of meat is also reported. Try using papaya enzyme after a meal to help break down meat or use a meat tenderizer before you cook meat.

Zinc, an essential trace mineral, is important for normal taste acuity. RYGBP surgery patients may have a decrease in zinc absorption as zinc is absorbed in the duodenum (first section of the small intestine). Also, zinc intake may decline in RYGBP because of decreased oral intake of meat. Animal proteins provide the most absorbable source of zinc.

Craving for Sweets

If you have cravings for something sweet, try one of the following:

  • Sugar-free hard candy or mints*
  • Sugar-free jello
  • Sugar-free gum
  • Sugar-free jam/jelly (2 teaspoons)
  • Sugar-free Popsicles
  • Sugar substitutes (saccharine, aspartame, sucralose, or acesulfame K)
  • Sugar-free diet drinks
  • Pancake syrup, sugar-free (1 to 2 tablespoons)
  • Whipped topping (2 tablespoons)

*If sweetened with sorbitol, limit to 2 pieces per day as excessive amounts of sorbitol may cause diarrhea.


Gallstones form when liquid stored in the gallbladder hardens into pieces of stone-like material. The liquid, called bile, is used to help the body digest fats. If bile contains too much cholesterol, bile salts, or bilirubin, it can harden into stones. Major factors contributing to gallstone formation are obesity, rapid weight loss, diabetes, cholesterol-lowering drugs, and women using birth control or on hormone therapy.

A gallstone attack can cause the following symptoms:

  • Steady, severe pain in the upper abdomen that increase rapidly and lasts from 30 minutes to several hours.
  • Pain in the back between the shoulder blades.
  • Pain under the right shoulder.
  • Nausea or vomiting

Approximately thirty percent of RYGB patients may develop gallstones and have to have their gallbladder removed (cholecystectomy) within the first 6 months after surgery.

Alcohol Intake

Alcoholic beverages supply calories but few or no nutrients essential for nutritional health. Drinking a lot of alcohol can result in high calorie intake and lead to weight gain. After RYGB surgery, the effects of alcohol are more rapid. Those with a family history of breast cancer, may want to consider abstaining from alcohol as drinking alcohol may increase your risk of breast cancer. Alcohol also reduces the effectiveness of antidepressants and should be avoided. Alcoholic beverages include wine, beer, and hard liquor.

Incisional Hernias

A sign of a hernia is a bulging under your incision area. After muscles have been cut through, the area is weakened. Lifting too much weight, pushing, or pulling during the first two months after surgery can result in a hernia. Remember, do not lift more than 15 pounds the first 6 weeks and no more than 25 pounds for the first 3 months after surgery. Have another family member vacuum, carry laundry, mow the lawn, etc. Enlist a neighbor or their teenage family members or folks from your local church to help you out. Consult your surgeon for surgical intervention, if indicated and appropriate.

Bulimia/Anorexia Nervosa

Bulimia and anorexia nervosa may be late complications of the RYGBP surgery and demand rigorous long term follow-up and psychotherapy.

People with bulimia nervosa consume large amounts of food and then rid their bodies of excess calories by vomiting, abusing laxatives or diuretics, taking enemas, or exercising obsessively. Some use a combination of all these forms of purging. Bulimia /bulimia nervosa patients, even those of normal weight, can severely damage their bodies by frequent binge eating and purging. In rare instances, binge eating and forceful vomiting causes the stomach to rupture. Purging may result in heart failure due to loss of vital minerals, such as potassium. These problems, combined with their impulsive tendencies, place them at increased risk for suicidal behavior.

Anorexia nervosa is the condition where people intentionally starve themselves. Starvation can damage vital organs such as the heart and brain. To protect itself, the body shifts into “slow gear”. Monthly menstrual periods stop, breathing, pulse, and blood pressure rates drop, and thyroid function slows. Nails and hair become brittle. Skin can become dry, yellow, and covered with soft hair called “lanugos.” Excessive thirst and frequent urination may occur. Dehydration contributes to constipation, and reduced body fat leads to lowered body temperature and the ability to withstand cold. Mild anemia, swollen joints, reduced muscle mass, and lightheadedness also commonly occur. If the disorder becomes severe, patients may also lose calcium from their bones, making them brittle and prone to breakage. They may also experience irregular heart rhythms and heart failure. In some patients, the brain shrinks, causing personality changes. Fortunately, this condition can be reversed when normal weight is reestablished.

For further reading on anorexia nervosa, click here


Pregnancy, early after RYGB surgery, may be particularly hazardous to mother and child because of rapid weight loss and poor nutrition. The effects of ketosis on pregnancy are not fully understood at this time. It is recommended to wait 1½ to 2 years after surgery when weight loss has subsided and stabilized.

As nutritional needs increase in pregnancy and the developing fetus, it is important that weight loss is stable and nutrition counseling is sought to meet the needs of both mother and child.


Depression was found to be the most common in those patients who had excellent results after surgery and it was concluded that “the marked weight loss leads to problems of adaptation, which in turn may trigger depressive reactions.”

Signs of depression:

  • Persistent sad, anxious, or empty mood
  • Feelings of guilt, worthlessness, helplessness, or hopelessness
  • Loss of interest or pleasure in hobbies and activities you once enjoyed, including sex
  • Insomnia, early morning awakening or oversleeping
  • Appetite and/or weight loss OR overeating and weight gain
  • Decreased energy, fatigue, being “slowed down” etc.

Treatment may include use of antidepressant medications and/or psychotherapy. Medication is used to gain relatively quick symptom relief. Psychotherapy is useful in learning more effective ways to deal with life’s problems. Please note that people can be successfully treated for depression on an outpatient basis.

Uric Acid

Rapid weight loss and ketosis after RYGB surgery may elevate uric acid. As weight loss occurs, uric acid levels will increase worsening gout symptoms. Uric acid levels usually return to normal by the end of the first year after RYGB surgery.


Ketones are substances formed as by-products of fat breakdown. They are produced and accumulated in the body when very large amounts of fat and very small amounts of carbohydrate and protein are consumed.

With RYGB surgery, you are only consuming approximately 500-600 calories per day for the first two months. Your body goes into ketosis because it is using your excess body fat for an energy source. Some side effects of ketosis are nausea, tiredness, and dizziness. After about six weeks, your body will adjust to using fat as a fuel source and most of these symptoms will disappear.

Body Image Perceptions

Body image refers to one’s mental picture of his/her outward appearance. This image is often distorted as we carry with us outdated or past images of pudgy childhoods or awkward adolescent bodies. In this society, it is often hard to live with media-set standards of attractiveness that most cannot and should not measure up to. Weight loss is often entered into primarily to improve one’s attractiveness and appeal rather than for health reasons.

It is important that as weight loss occurs, to focus on your strengths rather than your weaknesses.

Positive changes:

  1. Wear clothing that fits properly. Clothes that are too big and unflattering can make one feel unattractive. Come to the clothing exchanges at the support group meeting or go to consignment shops to buy and trade clothing while you are going down in size. E-bay also has some great deals!
  2. Think positive thoughts rather than negative ones. Negative self-talk only results in shame, guilt, and lowering self-esteem.
  3. Take a picture every month after surgery and keep them in a photo album so you have a visual image and not a mirror image perception of your body as it changes.
  4. Look at other peoples’ bodies at work, in restaurants, in stores, airports, etc. Notice their body language and how they project feeling good about themselves through the way they dress, stand, and act. Notice the wide variety of body types and appreciate the differences that make us interesting and unique.
  5. Ask friends, families for a reality check in comparing yourself to other people who may have the same body type or weight that you do. This may help a great deal in closing the gap between how you really look and how you think you look.
  6. As you lose weight, look at realistic ways to measure your body changes. Compare clothing sizes now vs. pre­-weight loss size. Keep one outfit from your starting size to try on and see the difference. Keep your body measurements monthly.

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