Gastric bypass surgery has been seen in the past as one of the most effective therapies in treating or reversing type 2 diabetes.
And now we know why.
It isn’t the surgery itself, as was once presumed, but the resulting weight loss.
Experts say this means major weight loss through dieting produces the same beneficial metabolic effects as surgery-induced weight loss.
That contention is at the heart of a new study from Washington University School of Medicine in St. Louis, Missouri.
Researchers studied people with obesity and type 2 diabetes who had undergone gastric bypass surgery and then lost 18 percent of their body weight.
They compared these study participants with others who also had diabetes and obesity but had lost the same percentage of body weight through diet alone.
The health improvements across both groups included lower blood sugar levels throughout the day, improved insulin action in the liver, muscle, and fat tissue, and a reduction in the need for insulin and other diabetes medications.
Dr. Vijaya Surampudi, an internal medicine specialist at Ronald Reagan UCLA Medical Center in California, says weight loss can have numerous health benefits.
“It can improve blood glucose control, blood pressure, reduce cholesterol, improve mood, and reduce depressive symptoms,” Surampudi told Healthline.
“There is also some evidence of prevention of certain cancers, including breast and colorectal cancer. And weight loss can improve functional capacity,” she added.
But that doesn’t mean losing weight is necessary for everyone’s health.
“People vary in the ‘ideal’ body fat/weight range for them,” said Krista Scott-Dixon, PhD, the director of curriculum at Precision Nutrition.
“What is ‘ideal’ is not a specific number, but rather a set of indicators about physical function, well-being, and thriving,” she told Healthline.
Scott-Dixon adds that different ethnic groups and genetic subpopulations can be healthy and functional with different body mass indexes (BMIs), body weights, and body fat percentages.
“For instance, we know that folks whose ancestors have East Asian genetic heritage tend to be less healthy at a lower BMI than folks from other regions,” she explained.
“When determining if weight loss is recommended, a medical professional will consider not just BMI, but weight distribution (adipose tissue volume and location), medical history, family history, and/or current lifestyle,” said Caroline West Passerrello, MS, RDN, LDN, a spokesperson for the Academy of Nutrition and Dietetics.
Scott-Dixon says high levels of body fat can change the hormonal and chemical environment within the body.
These changes can elevate a person’s risk for conditions such as:
“And when body fat gets too high, it starts depositing into places where it shouldn’t be, or shouldn’t be in high amounts,” she said.
These areas include the heart, liver, kidneys, muscle tissue, bone, and in and around other internal organs.
“Past a certain point, excess body weight loads our structures — primarily our joints in the lower body,” Scott-Dixon said.
For example, Surampudi says 1 pound of weight loss is 4 pounds off your knees and ankles.
Surampudi says bariatric surgery is simply “a tool in one’s health journey for weight loss.”
She adds that there are several types of bariatric surgeries, but the two most commonly offered are the gastric sleeve and the gastric bypass surgery.
“The decision on which surgery [is appropriate] is based on the individual patient, their medical history, and what the individual and their physician feels is the best choice,” she explained.
But surgical weight loss, including gastric bypass surgery, isn’t for everyone, says Scott-Dixon.
“So, individuals looking to improve their glucose control need to know they have options to reduce their adipose tissue volume,” she said.
Passerrello has these general tips for weight loss:
“It’s also accurately stated [in the study] that losing 18 percent of body weight with diet therapy alone is difficult,” Passerrello told Healthline.
Scott-Dixon says it’s also difficult to maintain in the long run.
“In part, this is because most traditional diets are not only nutritionally poor and relatively unsustainable, they’re also done in a context where building ‘deep health’ and the broad foundation for long-term changes aren’t addressed,” she said.
Scott-Dixon defines the concept of deep health as that which addresses a multifaceted set of indicators, including:
“There are so many things to consider: your access to food, your schedule, your current medical history, and your lifestyle, to name a few,” Passerrello said.
“A registered dietitian may use the social ecological model of health to frame a plan that will address these factors, as well as the amount of food to eat and how much movement to strive for,” she added.