Health Risks of Being Overweight

Type 2 diabetes is a disease in which blood sugar levels are above normal. High blood sugar is a major cause of coronary heart disease, kidney disease, stroke, amputation, and blindness.

Type 2 diabetes is the most common type of diabetes. This form of diabetes is most often associated with old age, obesity, family history of diabetes, previous history of gestational diabetes, and physical inactivity. The disease is more common among certain ethnic populations.

More than 85 percent of people with type 2 diabetes are overweight. It is not known exactly why people who are overweight are more likely to develop this disease. It may be that being overweight causes cells to change, making them resistant to the hormone insulin. Insulin carries sugar from blood to the cells, where it is used for energy. When a person is insulin resistant, blood sugar cannot be taken up by the cells, resulting in high blood sugar. In addition, the cells that produce insulin must work extra hard to try to keep blood sugar normal. This may cause these cells to gradually fail.

You may lower your risk for developing type 2 diabetes by losing weight, and increasing the amount of physical activity you do. If you have type 2 diabetes, losing weight and becoming more physically active can help you control your blood sugar levels and prevent or delay complications. Losing weight and exercising more may also allow you to reduce the amount of diabetes medication you take. The Diabetes Prevention Program, a large clinical study sponsored by the National Institutes of Health, found that losing just 5 to 7 percent of your body weight and doing moderate-intensity exercise for 30 minutes a day, 5 days a week, may prevent or delay the onset of type 2 diabetes.

Cancer occurs when cells in one part of the body, such as the colon, grow abnormally or out of control. The cancerous cells sometimes spread to other parts of the body, such as the liver.

Being overweight may increase the risk of developing several types of cancer, including cancers of the colon, esophagus, and kidney. Overweight is also linked with uterine and postmenopausal breast cancer in women. Gaining weight during adult life increases the risk for several of these cancers, even if the weight gain does not result in overweight or obesity.

It is not known exactly how being overweight increases cancer risk. It may be that fat cells release hormones that affect cell growth, leading to cancer. Also, eating or physical activity habits that may lead to being overweight may also contribute to cancer risk.

Avoiding weight gain may prevent a rise in cancer risk. Healthy eating and physical activity habits may lower cancer risk. Weight loss may also lower your risk, although studies have been inconclusive.

Osteoarthritis is a common joint disorder that causes the joint bone and cartilage (tissue that protects joints) to wear away. Osteoarthritis most often affects the joints of the knees, hips, and lower back.

Extra weight may place extra pressure on joints and cartilage, causing them to wear away. In addition, people with more body fat may have higher blood levels of substances that cause inflammation. Inflammation at the joints may raise the risk for osteoarthritis.

Weight loss of at least 5 percent of your body weight may decrease stress on your knees, hips, and lower back, and lessen inflammation in your body. If you have osteoarthritis, losing weight may help improve your symptoms.

Fatty liver disease occurs when fat builds up in the liver cells and causes injury and inflammation in the liver. It can sometimes lead to severe liver damage, cirrhosis (build-up of scar tissue that blocks proper blood flow in the liver), or evenliver failure. Fatty liver disease is like alcoholic liver damage, but it is not caused by alcohol and can occur in people who drink little or no alcohol.

People who have diabetes or "pre-diabetes" (when blood sugar levels are higher than normal but not yet in the diabetic range) are more likely to have fatty liver disease than people without these conditions. It is not known why some people who are overweight or diabetic get fatty liver disease and others do not.

Losing weight and being physically activecan help you control your blood sugar levels. It can also reduce the build-up of fat in your liver and prevent further injury. People with fatty liver disease should avoid drinking alcohol.

Gallbladder disease includes gallstones and inflammation or infection of the gallbladder. Gallstones are clusters of solid material that form in the gallbladder. They are made mostly of cholesterol and can cause abdominal pain, especially after consuming fatty foods. The pain may be sharp or dull.

People who are overweight have a higher risk for developing gallbladder disease. They may produce more cholesterol (a fat-like substance found in the body), a risk factor for gallstones. Also, people who are overweight may have an enlarged gallbladder, which may not work properly.

Fast weight loss (more than 3 pounds per week) or large weight loss can actually increase your chance of developing gallstones. Modest, slow weight loss of about 1/2 to 2 pounds a week is less likely to cause gallstones. Achieving a healthy weight may lower your risk for developing gallstones.