Understanding metabolic and bariatric surgery and how it helps people lose weight
Surgery basics
It’s helpful to start with how your digestive system works before surgery.
Your digestive system before surgery
- Food travels to your stomach, where it is broken down.
- From the stomach, the food travels to the small intestine.
- In the first part of the small intestine (called the duodenum), digestive juices from other organs break the food down so it’s small enough for your body to absorb.
- The smaller particles of food continue to move through the small intestine (jejunum then ileum). As this happens, the small intestine absorbs fats, calories, vitamins, and other nutrients.
- Anything your body doesn’t absorb moves through the large intestine (colon) and out as waste.
How is the surgery done?
Open surgery (less common). One long incision is made, and the operation is done through that opening.
Minimally invasive surgery (most common). These surgeries include laparoscopic or robotic-assisted operations. Tiny incisions are made on the abdominal wall through which a small camera and thin instruments are inserted to perform the operation. The abdomen is filled with a gas to create space for the surgeon to operate. This approach helps minimize pain, speed up recovery after surgery, and reduce complications.
The weight loss results after bariatric surgery are similar for both surgical approaches. However, people have a faster recovery time and fewer complications from minimally invasive surgery.
How does surgery change your digestive system?
Restriction
Surgery makes your stomach smaller, thereby limiting how much you can eat.
Malabsorption
Surgery changes how your digestive system absorbs food.
Hormone changes
Surgery changes the levels of certain hormones that affect hunger, the desire for food, and the feeling of fullness after eating.
Surgical approaches
Bariatric surgery works through 3 main mechanisms: restriction, malabsorption, and hormone changes. These 3 main mechanisms will impact the body in varying degrees based on the type of surgery you have.
You and your surgeon will discuss your options and decide on the best surgical approach for you based on your health and weight loss needs.
Restriction
The stomach is made smaller, thereby limiting how much you can eat. Most bariatric surgeries use this. One example is sleeve gastrectomy.
Malabsorption
The digestive tract is altered, which affects how it absorbs food. The intestines are rearranged and reconnected in these surgeries, which make them more complex. One example is gastric bypass.
Some other bariatric surgeries use these tools to help with weight loss. Based on your surgeon’s clinical judgment, they may also discuss these options with you during your consultation.
How long does surgery take?
Surgery can range from less than an hour to a couple hours depending on the operation. Nearly all operations are done using minimally invasive surgery, with most completed as same-day surgeries. Some operations may require a short hospital stay.
