The gastric bypass helps you lose weight by creating a smaller stomach pouch and rerouting the path that food normally takes so you feel full faster and eat less.

Losing Weight With Gastric Bypass

The gastric bypass works by creating a smaller stomach pouch and rerouting the path that food normally takes so that it “bypasses” a large section of the stomach and a portion of the small intestine.  

The result is an early sense of fullness and satiety that reduces the desire to eat. Not only do patients who’ve undergone gastric bypass surgery lose weight because they cannot eat as much, they also absorb fewer calories. This dual approach – restrictive (restricts the amount of food) and malabsorptive (reduces the amount of calories absorbed) – jump starts weight loss. In addition, the gastric bypass also causes the secretions of fewer hunger hormones – grehlins – resulting in less overall hunger further contributing to weight loss.

New Jersey Bariatric Center® patients who undergo a gastric bypass surgery typically lose between 65-70% of their excess body weight.

How Much Weight Can I Lose With Gastric Bypass?

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Health Improvements and Benefits

The gastric bypass procedure results in sustained, long-term weight loss and, improves and in some cases resolves obesity-related illnesses such as:

Type 2 Diabetes

77% of patients have resolution2


62% of patients have resolution2

Sleep Apnea

84% of patients have resolution2

With type 2 diabetes, many patients stop taking their diabetic or high blood pressure medication before they leave the hospital and before weight loss. With sleep apnea, there is improvement or complete resolution as weight loss results in the opening of air passages.



As with any surgery, there are risks to weight loss procedures. When deciding whether gastric bypass surgery is right for you, the potential health benefits must outweigh the potential risks. To learn more about specific complications associated with gastric bypass, visit our Risks page.

Do I Qualify for Gastric Bypass Surgery?

To qualify for gastric bypass surgery, a body mass index (BMI) of 40 or greater, or a BMI of 35 with obesity-related conditions such as diabetes, high blood pressure or sleep apnea should exist.  

Gastric Bypass Procedure

At New Jersey Bariatric Center® surgeons perform the gastric bypass procedure laparoscopically through approximately four or five incisions in the abdomen. The surgeons staple off a section of the stomach, leaving the rest of the stomach in place and creating a pouch that can hold about a quarter-cup of food. The top part of the small intestine is then divided, and the bottom half of the divided small intestine is connected to the new, small pouch. Food bypasses the stapled-off section of the stomach and the upper portion of the small intestine. The procedure lasts approximately 2-3 hours. 

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Recovery and Follow-Up

On average, New Jersey Bariatric Center® patients leave the hospital within 1-2 days after gastric bypass surgery. When planning for the period after having a gastric bypass operation, you should keep the following in mind:

  • Allow yourself time to adjust to your new lifestyle. You’ll need time to figure out how your new routine of healthy food and exercise fits into your life.
  • No heavy lifting for 4 to 6 weeks post-surgery. No more than 15 pounds.
  • You will be physically able to return to work between 1 week and 3 weeks after surgery, depending on the type of work you do.
  • You will have the support of our dedicated team of medical professionals who will work with you on nutrition, exercise, psychological and physical therapy needs both before surgery and for the long-term.

Gastric Bypass FAQs

To qualify for gastric bypass surgery you must have a body mass index (BMI) of 40 or greater or a BMI of 35 or greater with one or multiple obesity-related health problems such as type 2 diabetes, sleep apnea and high blood pressure. One of our fellowship-trained surgeons can help you determine if gastric bypass surgery is right for you.
Many weight loss surgery patients are surprised to learn that hair loss is a common side effect of bariatric surgery and it doesn’t matter if you’ve had Gastric Bypass or Gastric Sleeve. The truth is many patients will experience some degree of hair-thinning, especially between the third and sixth month after surgery. The good news is that there are several treatment options for this problem. And the better news is that since the hair follicles are not damaged, the hair will grow back. Read more here.
It’s important to know that weight loss surgery is a tool to jumpstart weight loss. Long term success after gastric bypass or any other weight loss surgery is achieved through lifestyle changes, maintaining a healthy diet and exercise to avoid weight regain.
If you are a woman of child-bearing age, it is strongly advised that you wait at least a year before trying to conceive because bariatric surgery patients lose weight quickly during the first year, and it may be difficult to support the nutrition of both mom and baby during this period of rapid weight loss. By delaying a pregnancy, you are better assured that you will be able to get the proper nutrition for the health of your baby and yourself. The weight you are able to lose after surgery can significantly reduce the risks of gestational diabetes, preeclampsia, pre-term labor, postpartum bleeding, infant mortality and other pregnancy-related complications. It has been published that a woman can reduce these risks by losing as little as 5% of her weight. Losing more than that with bariatric surgery – gastric bypass or gastric sleeve – could make pregnancy even safer. Consult your gynecologist to help you plan for pregnancy.
Weight loss surgery is just the first step in a lifelong commitment toward better health. When deciding which procedure is right for you, keep in mind that surgery is only a tool. Your ultimate success depends on your adherence to the recommended dietary, exercise and lifestyle changes. Not all weight loss surgery procedures are the same. If you qualify, our team will guide you in deciding which procedure will give you the best chance for success based on factors such as your current weight and your ability to follow the post-surgical guidelines. For more info on each procedure, click here.

Gastric Bypass Patient Stories

Carmen Lost 118 Lbs.*

Willie Lost 200 Lbs.*

Martiza Lost 90 Lbs.*






  1. Bariatric Surgery Procedures. (n.d.). In American Society for Metabolic and Bariatric Surgery. Retrieved December 3, 2020, from https://asmbs.org/patients/bariatric-surgery-procedures#learnmore
  2. Metabolic and bariatric surgery. (2018, October). In American Society for Metabolic and Bariatric Surgery. Retrieved November 10, 2020, from https://asmbs.org/resources/metabolic-and-bariatric-surgery