Heart disease, high blood pressure, and diabetes are just a few of the life-threatening reasons people consider having weight-loss surgery. But gastric bypass can bring complications of its own. That’s why doctors always have patients weigh the pros and cons of their decision carefully.

For Iowan Penny Wheeler, gastric bypass surgery was a way to hit her target weight-loss goal after gaining a lot of weight following successful cancer treatment. At her peak of 330 pounds, all dieting solutions had failed and doctors gave her a dire warning.

"If you don’t have this surgery, you will die within a year. That was an eye opener right there," says Wheeler.

Mayo Clinic gastrointestinal surgeon Michael Sarr, MD, performed a Roux-en Y procedure on Wheeler, which decreased the length of her intestine where food is absorbed, minimizing the amount she could eat after surgery. When Dr. Sarr agreed to do the surgery, he told Wheeler everything else was up to her. She followed his advice and radically changed her lifestyle, starting an exercise program and making drastic dietary changes.

She found that she also had to appease a newly sensitive digestive tract. "Milk gets me sick," says Wheeler. "I was not lactose intolerant before the surgery, but I am now."

To fill nutritional deficits, gastric bypass patients need to take vitamins and calcium supplements, and patients on heart medications or immunosuppressive drugs need to be monitored closely, according to Sarr. He says that nearly half his pre-bypass patients struggle with depression, and even successful weight loss can create emotional strain.

"Spouses may have trouble. You get comfortable with your spouse and then one of them loses weight and the other doesn't," says Sarr. "There can be some jealousy there."

There can also be side effects from the surgery. Scarring from Wheeler’s bypass contributed to an intestinal blockage, which required follow-up surgery. But Sarr says there are major benefits as well. Diabetic patients often see their insulin usage or medication needs decrease dramatically. Likewise, high pressure becomes easier to control. "We expect 80-percent of people to decrease the amount of medicines they're on, 50-percent to get off their anti-hypertensive,” Sarr notes.

Despite complications and side effects Wheeler endured, she doesn't regret having gastric bypass surgery. The benefits were life-saving – and life-changing.