December 14, 2012
Dear Mayo Clinic:
Can type 2 diabetes be cured just by losing weight?
Losing weight can have a big impact on diabetes. Although it might not cure type 2 diabetes in every case, getting to a healthy body weight does have that potential for many people. Even if it doesn't completely cure the disease, losing weight may make it possible for people with diabetes to take less medication. It often helps manage or prevent some of the health problems that can come with diabetes, too.
People who have diabetes have too much sugar in their blood. This happens because of a problem with the hormone called insulin. Insulin is made in the pancreas — a gland located just behind the stomach. When you eat, the pancreas releases insulin into your bloodstream. The insulin allows sugar to enter your cells, lowering the amount of sugar in your blood.
If you have type 2 diabetes, the pancreas does not make enough insulin or your body cannot use insulin as well as it should. So sugar cannot move into your cells. Instead, it builds up in your blood.
The reason why type 2 diabetes develops is not completely clear. But being overweight plays a role. In people who are overweight, the body sometimes needs as much as two to three times more insulin than it would if it was at a healthy weight. In those who develop diabetes, that is more insulin than the pancreas is able to produce.
When the pancreas tries to make that much insulin, it is pushed beyond its capacity and insulin-producing cells start to die. That makes the situation worse because the pancreas then has even fewer cells with which to make insulin. Compounding the problem, research also has shown that fat cells of people who are obese and who have more abdominal fat actually release molecules that can be harmful to the pancreas. So the more abdominal fat you have, the higher the risk of damage to your pancreas.
Getting to a lower weight reduces many of these problems. When you weigh less, your pancreas is better able to keep up with your body's need for insulin. In some cases, weight loss is enough to restore blood sugar to a normal level, which eliminates diabetes. Even if it doesn't get your blood sugar completely back to normal, it may lower your need for insulin therapy or other medications to control diabetes. It also lessens your risk for other serious complications of diabetes, including heart problems, kidney disease and nerve damage.
The benefits of healthy weight as it relates to diabetes continue over time, too. Many people mistakenly believe that a person's risk for diabetes automatically goes up with age. In fact, your diabetes risk rises over time only if you gain weight and are less active as you age. For those who stay fit, the risk of developing diabetes remains the same or increases only slightly.
For those with a family history of diabetes, weight control is critical. Research has shown that people who have a family history of type 2 diabetes are more vulnerable to developing type 2 diabetes themselves. Staying at a healthy weight lowers their chances of getting the disease by about 70 to 90 percent.
In general, healthy weight is defined as a body mass index, or BMI, of 25 or lower. To get there, you don't need to run marathons or do hours of workouts each day. But you do need to be active on a regular basis. If you are interested in losing weight, talk to your doctor about an exercise and diet program that best fits your needs.
— Robert Rizza, M.D., and Michael Jensen, M.D., Endocrinology, Mayo Clinic, Rochester, Minn.