Heart Disease and Stroke
Heart disease and stroke are the leading causes of death and disability for both men and women in the United States. Overweight people are more likely to have high blood pressure, a major risk factor for heart disease and stroke, than people who are not overweight. Very high blood levels of cholesterol and triglycerides (blood fats) can also lead to heart disease and often are linked to being overweight. Being overweight also contributes to angina (chest pain caused by decreased oxygen to the heart) and sudden death from heart disease or stroke without any signs or symptoms. The good news is that losing a small amount of weight can reduce your chances of developing heart disease or a stroke. Reducing your weight by 10 percent can decrease your chance of developing heart disease by improving how your heart works, blood pressure, and levels of blood cholesterol and triglycerides

Diabetes
Noninsulin-dependent diabetes mellitus (type 2 diabetes) is the most common type of diabetes in the United States. Type 2 diabetes reduces your body's ability to control your blood sugar. It is a major cause of early death, heart disease, kidney disease, stroke, and blindness. Overweight people are twice as likely to develop type 2 diabetes as people who are not overweight. You can reduce your risk of developing this type of diabetes by losing weight and by increasing your physical activity. If you have type 2 diabetes, losing weight and becoming more physically active can help control your blood sugar levels. If you use medicine to control your blood sugar, weight loss and physical activity may make it possible for your doctor to decrease the amount of medication you need.

Sleep Apnea
Sleep apnea is a serious condition that is closely associated with being overweight. Sleep apnea can cause a person to stop breathing for short periods during sleep and to snore heavily. Sleep apnea may cause daytime sleepiness and even heart failure. The risk for sleep apnea increases with higher body weights. Weight loss usually improves sleep apnea.

Cancer
Several types of cancer are associated with being overweight. In women, these include cancer of the uterus, gallbladder, cervix, ovary, breast, and colon. Overweight men are at greater risk for developing cancer of the colon, rectum, and prostate. For some types of cancer, such as colon or breast, it is not clear whether the increased risk is due to the extra weight or to a high-fat and high-calorie diet.

Osteoarthritis
Osteoarthritis is a common joint disorder that most often affects the joints in your knees, hips, and lower back. Extra weight appears to increase the risk of osteoarthritis by placing extra pressure on these joints and wearing away the cartilage (tissue that cushions the joints) that normally protects them. Weight loss can decrease stress on the knees, hips, and lower back and may improve the symptoms of osteoarthritis.

Gout
Gout is a joint disease caused by high levels of uric acid in the blood. Uric acid sometimes forms into solid stone or crystal masses that become deposited in the joints. Gout is more common in overweight people and the risk of developing the disorder increases with higher body weights. Note: Over the short term, some diets may lead to an attack of gout in people who have high levels of uric acid or who have had gout before. If you have a history of gout, check with your doctor or other health professional before trying to lose weight.

Gallbladder Disease
Gallbladder disease and gallstones are more common if you are overweight. Your risk of disease increases as your weight increases. It is not clear how being overweight may cause gallbladder disease. Weight loss itself, particularly rapid weight loss or loss of a large amount of weight, can actually increase your chances of developing gallstones. Modest, slow weight loss of about 1 pound a week is less likely to cause gallstones.