Understanding the Gastrointestinal Tract
To better understand how weight loss surgery produces change, it is important to understand how your gastrointestinal tract functions. As the food you consume moves through the tract, various digestive juices and enzymes are introduced at specific stages that allow absorption of nutrients. Food material that is not absorbed is then prepared for elimination. A simplified description of the gastrointestinal tract appears below. Your doctor can provide a more detailed description to help you better understand how weight loss surgery works.
- The esophagus is a long muscular tube, which moves food from the mouth to the stomach.
- The abdomen contains all of the digestive organs.
- The stomach, situated at the top of the abdomen, normally holds just over 3 pints (about 1500 ml) of food from a single meal. Here the food is mixed with an acid that is produced to assist in digestion. In the stomach, acid and other digestive juices are added to the ingested food to facilitate the breakdown of complex proteins, fats, and carbohydrates into small, more absorbable units.
- A valve at the entrance to the stomach from the esophagus allows the food to enter while keeping the acid-laden food from "refluxing" back into the esophagus, causing damage and pain.
- The pylorus is a small round muscle located at the outlet of the stomach and the entrance to the duodenum (the first section of the small intestine). It closes the stomach outlet while food is being digested into a smaller, more easily absorbed form. When food is properly digested, the pylorus opens and allows the contents of the stomach into the duodenum.
- The small intestine is about 15 to 20 feet long (4.5 to 6 meters) and is where the majority of the absorption of the nutrients from food takes place. The small intestine is made up of three sections: the duodenum, the jejunum and the ileum.
- The duodenum is the first section of the small intestine and is where the food is mixed with bile produced by the liver and with other juices from the pancreas. This is where much of the iron and calcium is absorbed.
- The jejunum is the middle part of the small intestine extending from the duodenum to the ileum; it is responsible for digestion.
- The last segment of the intestine, the ileum, is where the absorption of fat-soluble vitamins A, D, E and K and other nutrients are absorbed.
- Another valve separates the small and large intestines to keep bacteria-laden colon contents from coming back into the small intestine.
- In the large intestines, excess fluids are absorbed and a firm stool is formed. The colon may absorb protein, when necessary.
Development of Surgical Treatments for Obesity
The concept for bariatric surgery, or the surgical treatment of obesity, came about somewhat serendipitously. In the course of removing large portions of the stomach or small intestine in patients with cancer or severe ulcers, surgeons noticed an interesting trend. The patients tended to lose weight. Over the past 50 years, numerous world-class surgeons have taken part in exploring this concept. As with anything, there was a learning curve. But the mistakes and shared global data have helped other innovators to improve upon the techniques and bring bariatric surgery into the modern age. The bariatric surgery procedures available today have either stood the test of time or drawn from the lessons learned by the early pioneers. As a result, bariatric surgery treatment for obesity has never been as safe or as effective. In Summary, Bariatric patients have more choices than ever, not to mention better and safer ones. Operative mortality for most contemporary weight loss surgeries has fallen to less than 1% while permanent and significant weight loss has been achieved in multiple published reports. For the growing population of morbidly obese Americans, bariatric surgery has cemented its place as the most effective weight loss treatment available.
Bariatric Surgery as Treatment for Obesity
There is considerable misinformation concerning the validity of bariatric surgery in the management of morbid obesity. Bariatric Surgery (also referred to as "gastric surgery", "obesity surgery", "stomach stapling", and "gastric bypass") has been endorsed by the National Institutes of Health Consensus Conference, 1992. The American Society for Bariatric Surgery is recognized by the American College of Surgeons and a specialty surgical society in the Specialty & Service Society section of the American Medical Association. It must be emphasized that these procedures are in no way to be considered as cosmetic surgery.
The American Society for Bariatric Surgery reports surgical treatment is medically necessary because it is the only proven method of achieving long term weight control for the morbidly obese. Surgical treatment is not a cosmetic procedure. Bariatric surgery involves reducing the size of the gastric reservoir, with or without a degree of associated malabsorption. Eating behavior improves dramatically. (1) This reduces caloric intake and ensures that the patient practices behavior modification by eating small amounts slowly, and chews each mouthful well.
Current medical standards suggest that patients whose BMI exceed 40 (or 35-39 with life threatening co-morbidities) are potential candidates for weight loss surgery if they strongly desire substantial weight loss because obesity morbidly impairs the quality of their lives. They must clearly and realistically understand how their lives may change after the operation.
The American Society for Bariatric Surgery reports that weight loss usually reaches a maximum between 18 and 24 months postoperatively. Mean percent excess weight loss at five years ranged from 48 to 74% after gastric bypass and from 50 to 60% after vertical banded gastroplasty. In a study of over 600 patients following gastric bypass, with 96% follow-up, mean percent excess weight loss still exceeds 50% after fourteen years. Another 10-year follow-up series from the University of Virginia report weight loss of 60% of excess weight at 5 years and in the mid 50's between years 6 and 10. Multiple other authors have reported 5 and 6-year follow-up of their patient series with similar weight loss results.
The American Society for Bariatric Surgery reports weight reduction surgery has been reported to improve several co morbid conditions such as glucose intolerance and frank diabetes mellitus, sleep apnea and obesity associated hypoventilation, hypertension, and serum lipid abnormalities. A recent study showed that Type II diabetics treated medically had a mortality rate three times that of a comparable group who underwent gastric bypass surgery. Also, preliminary data indicate improved heart function with decreased ventricular wall thickness and decreased chamber size with sustained weight loss. Other benefits observed in some patients after surgical treatment include improved mobility and stamina. Many patients note a better mood, self-esteem, interpersonal effectiveness, and an enhanced quality of life. They are able to explore social and vocational activities formerly inaccessible to them. Self-body image disparagement decreases.
1. Rand CS, Macgregor AM, Hankins GC. Eating behavior after gastric bypass surgery for obesity. South Med J 1987; 80(8): 961-4.
How Effective Is Weight Loss Surgery?
- The actual weight a patient will lose after the weight loss surgery is dependent on several factors. These include:
- Patient's age
- Weight before weight loss surgery
- Overall condition of patient's health
- Surgical procedure
- Ability to exercise
- Commitment to maintaining dietary guidelines and other follow-up care
- Motivation of patient and cooperation of their family, friends, and associates
In general, weight loss surgery success is defined as achieving loss of 50% or more of excess body weight and maintaining that level for at least five years. Clinical data will vary for each of the different procedures mentioned on this site. Results may also vary by surgeon. Ask your doctor for the clinical data stating their results of the procedure they are recommending.
Clinical studies show that, following weight loss surgery, most patients lose weight rapidly and continue to do so until 18 to 24 months after the procedure. Patients may lose 30 to 50% of their excess weight in the first six months and 77% of excess weight as early as 12 months after weight loss surgery. Another study showed that patients can maintain a 50-60% loss of excess weight 10-14 years after weight loss surgery. Patients with higher initial BMIs tend to lose more total weight. Patients with lower initial BMIs will lose a greater percentage of their excess weight and will more likely come closer to their ideal body weight.
Patients with Type 2 Diabetes tend to show less overall excess weight loss than patients without Type 2 Diabetes. Weight loss surgery has been found to be effective in improving and controlling many obesity-related health conditions. A 2000 study of 500 patients showed that 96% of certain associated health conditions studied (back pain, sleep apnea, high blood pressure, diabetes, and depression) were improved or resolved. For example, many patients with Type 2 Diabetes, while showing less overall excess weight loss, have demonstrated excellent resolution of their diabetic condition, to the point of having little or no need for continuing medication.
How Bariatric Surgery Produces Change
Surgeons first began to recognize the potential for weight loss surgery while performing operations that required the removal of large segments of a patient's stomach and intestine. After the surgery, doctors noticed that in many cases patients were unable to maintain their pre-surgical weight. With further study, surgeons were able to recommend similar modifications that could be safely used to produce weight loss in morbidly obese patients. Over the last decade, these procedures have been continually refined in order to improve results and minimize risks. Today's bariatric surgeons have access to a substantial body of clinical data to help them determine which weight loss surgeries should be used and why.
Today, the American Society for Bariatric Surgery describes two basic approaches that weight loss surgery takes to achieve change:
- Restrictive procedures that decrease food intake.
- Malabsorptive procedures that alter digestion, thus causing the food to be poorly digested and incompletely absorbed so that it is eliminated in the stool.
Making Your Decision about Weight Loss Surgery
Weight loss surgery is major surgery. Although most patients enjoy an improvement in obesity-related health conditions (such as mobility, self-image, and self-esteem) after the successful results of weight loss surgery, these results should not be the overriding motivation for having the procedure. The goal is to live better, healthier and longer.
That is why you should make the decision to have weight loss surgery only after careful consideration and consultation with an experienced bariatric surgeon or a knowledgeable family physician. A qualified surgeon should answer your questions clearly and explain the exact details of the procedure, the extent of the recovery period and the reality of the follow-up care that will be required. They may, as part of routine evaluation for weight loss surgery, require that you consult with a dietician/nutritionist and a psychiatrist/therapist. This is to help establish a clear understanding of the post-operative changes in behavior that are essential for long-term success.
It is important to remember that there are no ironclad guarantees in any kind of medicine or surgery. There can be unexpected outcomes in even the simplest procedures. What can be said, however, is that weight loss surgery will only succeed when the patient makes a lifelong commitment. Some of the challenges facing a person after weight loss surgery can be unexpected. Lifestyle changes can strain relationships within families and between married couples. To help patients achieve their goals and deal with the changes surgery and weight loss can bring, most bariatric surgeons offer follow-up care that includes support groups, dieticians and other forms of continuing education.
Ultimately, the decision to have the procedure is entirely up to you. After having heard all the information, you must decide if the benefits outweigh the side effects and potential complications. This surgery is only a tool. Your ultimate success depends on strict adherence to the recommended dietary, exercise and lifestyle changes.
Preparing For Weight Loss Surgery
Weight loss surgery is like other major surgeries. The best preparation is to understand the risks and potential benefits and to closely follow your doctor's instructions.
- To mentally prepare yourself:
- Understand weight loss surgery and what to expect afterward.
- Talk to people who have had weight loss surgery.
- Write a letter to yourself and your surgeon explaining your reasons for wanting weight loss surgery and outlining your plans to maintain your weight loss after surgery.
- Start a journal about your experience. Record how you feel now, the obstacles you encounter, the things you hope to be able to do after surgery.
- Get a letter of support from your family. It helps to know you have people behind you, waiting to help.
- To physically prepare yourself, strictly follow your doctor's guidelines. These usually include, but are not limited to:
- Restricting yourself to a clear liquid diet 12-24 hours before surgery.
- Stop smoking for at least a month before surgery.
- Be certain to follow your surgeon's instructions regarding any medications you may be taking to control other health conditions.
- Arrive on time, with supplies from home for a three- to four-day hospital stay. If you use special equipment for sleep apnea, you should bring your machine to the hospital.
Post-Surgery Diet Modifications
The modifications made to your gastrointestinal tract will require permanent changes in your eating habits that must be adhered to for weight loss success. Post-surgery dietary guidelines will vary by surgeon. You may hear of other patients who are given different guidelines following their weight loss surgery that encourage weight loss success. It is important to remember that every surgeon does not perform the exact same weight loss surgery procedure and that the dietary guidelines will be different for each surgeon and each type of procedure. What is most important is that you adhere strictly to your surgeon's recommended guidelines so you too can achieve the weight loss success you desire. The following are some of the generally accepted dietary guidelines a weight loss surgery patient may encounter:
- GUIDELINES FOR WEIGHT LOSS SUCCESS
- When you start eating solid food it is essential that you chew thoroughly. You will not be able to eat steaks or other chunks of meat if they are not ground or chewed thoroughly.
- Don't drink fluids while eating. They will make you feel full before you have consumed enough food.
- Omit desserts and other items with sugar listed as one of the first three ingredients.
- Omit carbonated drinks, high-calorie nutritional supplements, milk shakes, high-fat foods and foods with high fiber content.
- Avoid alcohol.
- Limit snacking between meals.
This information provided by Ethicon Endo-Surgery Inc.
Surgical Weight Loss Support Groups
Weight loss support groups are an intricate part of your recovery from surgery and long-term weight loss maintenance. Weight loss support groups are forums that provide education, motivation, and can provide valuable input pre-operatively as well as postoperatively.
Weight loss support groups are conducted at various times, days and locations. An experienced health professional, physician and successful surgical weight loss patients put on the meetings. Support groups are hosted in a variety of ways. Many weight loss support groups provide speakers who discuss issues of interest while others lead their own educational speaking engagements or have group discussions. The support groups are for those that are doing well with their surgical procedure, those investigating surgery and those that may be struggling with their program.
Some weight loss support groups are held in the community setting and other support groups are provided by your surgeon. You are encouraged to get such information from his office.