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Weight Loss Surgery Health Center

Illustrated Guide: What to Expect With Weight Loss Surgery

photo of bariatric surgery target area

How Does Bariatric Surgery Work?

Bariatric surgery -- or weight loss surgery -- works in three basic ways: 1) restricts how much food your stomach can hold at any time, 2) prevents your digestive system from absorbing some of the nutrition in the food you eat, or 3) both. This guide uses imagery and animation to show you what to expect from weight loss surgery.

photo of body mass index

Bariatric Surgery: Requirements

  • Body mass index (BMI) greater than 40.
  • BMI of 35-40 for people with heart disease, diabetes, high cholesterol, or obstructive sleep apnea. Calculate your BMI.

Some doctors will consider surgery for people with a lower BMI of 30-34 and diabetes or metabolic syndrome.

In general, doctors operate on people younger than 65-70 who have been unable to achieve lasting weight loss with lifestyle changes and medications. Doctors encourage weight loss before surgery. This can help improve surgery results.

phot of gastric bypass surgery illustration

Types of Weight Loss Surgery

Gastric banding and gastroplasty ("stomach stapling") are restrictive procedures that decrease the stomach size from about 6 cups to 1. The gastric sleeve is a newer restrictive procedure that is another option. Malabsorptive procedures, which block food absorption, include gastric bypass. "Roux-en-Y" gastric bypass combines both approaches and is the most common weight loss surgery in the U.S. It reduces stomach size and prevents calorie absorption in the small intestine.

photo of gastric bypass surgery consultation

Before Weight Loss Surgery

You'll have one-on-one counseling, evaluation, and various tests. You have to get medical clearance to have surgery, and take steps like controlling blood sugar and quitting smoking before being approved. You'll also need to commit to long-term follow-up after surgery.

photo of glass of water before gastric bypass surgery

Preparing for Surgery

Preparation will depend on the specific procedure, and may include blood typing and other tests. You'll avoid aspirin or aspirin-containing products and herbal supplements 1 week before surgery, and take only clear liquids for 24-48 hours immediately before surgery. An IV will provide pain medication and sedation. Then, once you are asleep, a breathing tube will be inserted to help you breathe during the operation.

Surgical Methods

Your surgeon will use either the open or laparoscopic surgical method for your gastric bypass surgery, as shown in this animation.

Your 'New' Stomach is Created

During a "Roux-en-Y" gastric bypass procedure, surgical staples are used to create a small pouch to serve as your new stomach.

Creating the Stomach Bypass

The lower stomach and part of the small intestine are bypassed so that fewer calories will be absorbed when food passes through. The stomach remains in place. It makes digestive juices that help the small intestine to digest food.

Banding Techniques

Banding shrinks the stomach to a small pouch, and shrinks the exit to a very small opening, so food moves through slowly, making you feel full longer.

Biliopancreatic Diversion

This malapsorptive procedure greatly decreases the calories and nutrients absorbed in the small intestine.

photo of post gastric bypass surgery

After the Procedure

For all types of bariatric surgery, your surgeon will close the incision with surgical stitches or staples. Your IV and breathing tube will be removed. You will be monitored during a short hospital stay.You'll be given pain medications and watched closely for low blood sugar, dehydration, blood clots, and other potential problems. Laparoscopy leaves smaller scars than open surgery and tends to have fewer complications and quicker recovery time. Most gastric bypasses are laparascopic.

photo of spoon in soup bowl

Eating After Weight Loss Surgery

You'll be on a liquid diet at first. After a few weeks, you can eat solid foods. You will work closely with a nutritionist familiar with weight loss surgery to make an eating plan. You may not be able to eat what you did before surgery. You must eat smaller portions and fewer calories. Because of this, you'll need to make sure you get enough protein and supplements to make up for any nutrients you are missing.

photo of gastric bypass surgery patient

How Much Weight Will You Lose?

Weight loss may be dramatic in some cases -- as much as a pound a day in the first 3 months. Combination surgery, which causes malabsorption and shrinks the stomach, produces more weight loss than restriction-only operations. People who have bypass surgery generally lose two-thirds of their excess weight within 2 years. However, long-term weight loss is not guaranteed. To prevent regaining weight, it is important to keep following up with your bariatric health care team. Excess skin may need to be removed after rapid weight loss. This requires additional surgery.

photo of lap band surgery patient

Other Health Benefits

If you have high blood pressure, diabetes, or other health problems caused by being overweight, they may get better than before or go away as you lose weight. Your doctor will work with you to adjust any medications you take for those conditions. With successful weight loss, if you have arthritis or sleep apnea, your joint pain, breathing, and sleep may improve. And you may be able to be more physically active.

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Lifestyle Changes After Surgery

Weight loss surgery can produce dramatic results. But the gains from losing weight are not automatic. To be successful, the process requires permanent lifestyle changes. You'll need to eat small, frequent meals, and committ to good nutrition and exercise. You also should continue to follow-up with your bariatric care team long after surgery.

photo of lap band surgery

Risks of Gastric Bypass Surgery

All surgeries carry some risk. For bariatric surgery, the risk of dying is less than 1%, and serious complications after surgery are rare. People most at risk are older people, those with a history of deep-vein thrombosis (blood clots), and people who are severely obese. To have the best chance of avoiding complications, it's important to go to all your follow-up visits and stick to your prescribed diet and lifestyle plan.

photo of lap band patient

Complications After Surgery

People who've had bariatric surgery are at risk for problems including:

  • Pouch stretching back to stomach's original size
  • Vomiting from eating more than the stomach pouch can hold
  • The band disintegrating
  • Band and staples fall apart, reversing the procedure
  • Stomach contents leaking into the abdomen
  • Gallstones from excess weight loss
  • Nutritional deficiencies such as copper and vitamin deficiencies
  • Health problems like osteoporosis
  • A need to reopen and revise the surgery
photo of stomach problems after lap band surgery

Dumping Syndrome

Gastric bypass surgery also may cause food and drink that is in your stomach to move too quickly through your small intestine. Symptoms include nausea, weakness, sweating, faintness, and occasionally diarrhea after eating. You may also be unable to eat sweets without becoming extremely weak. To avoid these symptoms, follow your nutritionist's advice.

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Deficiencies and Supplements

After surgery, many people do not absorb vitamins A, D, E, K, B-12, iron, copper, calcium, and other vitamins and nutrients as well as they did before surgery. The more you have done during the surgery, the greater the risk for missing out on nutrients. Taking supplements can help you get enough nutrients and prevent conditions such as anemia and osteoporosis. Most people will need to be watched closely by their medical team and use of special foods and medications for life.

photo of gastric band

Risks of Gastric Banding

Although gastric banding is considered the least invasive of the weight loss surgeries, problems can occur, including:

  • Band slippage or erosion into the stomach
  • The passageway created by the band can be blocked by food
  • Access port leakage or infection
  • Esophagitis or gastroesophageal reflux disease (GERD)
  • Malnutrition
photo of life after lap band surgery

Adjusting to a New Life

It is common to have many different emotions after weight loss surgery. You may feel happy or excited as you begin to lose weight. But you may also feel overwhelmed or frustrated by the changes that you have to make in your diet, activity, and lifestyle. Talk with your doctor if you have concerns or questions.

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