Obesity is a serious, chronic disease that is known to reduce life span, increase disability and lead to many serious illnesses. These illnesses, including diabetes, heart disease, gallstones and stroke, are the co-morbidities of obesity. The Lewin study confirmed results from other studies in finding a direct correlation between increases in Body Mass Index (BMI) and increases in the prevalence ofco-morbid conditions, especially type 2 diabetes, hypertension, heart disease, stroke and arthritis:

Co-morbidity of Obesity: Cancer*
Cancer involves the uncontrolled growth of abnormal cells that have mutated from normal tissues. These cells prevent normal function of vital organs, damaging essential systems. 

Recent studies suggest that those with a BMI more than 40 (morbidly obese) had death rates from cancer that were 52 percent higher for men and 62 percent higher for women, as compared to rates for normal-weight men and women. In both men and women, higher BMI is associated with higher death rates from cancers of the esophagus, colon and rectum, liver, gallbladder, pancreas, and kidney. The same trend applies to cancers of the stomach and prostate in men, and cancers of the breast, uterus, cervix, and ovaries in women. 

Almost half of post-menopausal women diagnosed with breast cancer have a BMI greater than 29. One study indicates (the Nurses’ Health Study) women who gain more than 20 pounds from age 18 to midlife double their risk of breast cancer, compared to women whose weight remained stable.

Co-morbidity of Obesity: Diabetes*
Diabetes is a life-long disease marked by high levels of sugar in the blood. It can be caused by too little insulin (a hormone produced by the pancreas to regulate blood sugar), resistance to insulin, or both. 

Among those diagnosed with type 2 (non insulin-dependent) diabetes, 67 percent have a BMI greater than 27 and 46 percent have a BMI greater than 30. Nearly 17 million people in the U.S. have type 2 diabetes, accounting for more than 90 percent of diabetes cases. An additional 20 million have impaired glucose tolerance, sometimes called pre-diabetes, which is a strong risk factor for developing diabetes later in life. An estimated 70 percent of diabetes risk in the U.S. can be attributed to excess weight. Gastric Bypass Surgery eliminate Diabetes type II almost immediately.

Co-morbidity of Obesity: High Cholesterol*
Lipid disorders are when you have excess fatty substances in your blood. These substances include cholesterol and triglycerides. Having a lipid disorder makes you more likely to develop arteriosclerosis and heart disease. 

The prevalence of high blood cholesterol (greater than 240 mg/dL) in overweight U.S. adults is 19.1 percent for men with a BMI greater than 25 and less than 27; 21.6 percent for men with a BMI greater than 27 and less than 30; 30.5 percent for women with a BMI greater than 25 and less than 27; and 29.6 percent for women with a BMI greater than 27 and less than 30. 
 

Co-morbidity of Obesity: High Blood Pressure*
Blood pressure is measured in millimeters of mercury (mm Hg). Hypertension (high blood pressure) is when your blood pressure frequently goes over 140/90 mm Hg.

About 1 in every 5 adults in the U.S. has high blood pressure. High blood pressure occurs more often in men than in women. In addition, African Americans are affected almost twice as much as Caucasians. The prevalence of hypertension in overweight U.S. adults is 22.1 percent for men with a BMI greater than 25 and less than 27; 27.0 percent for men with a BMI greater than 27 and less than 30; 27.7 percent for women with a BMI greater than 25 and less than 27; and 32.7 percent for women with a BMI greater than 27 and less than 30. 
 

Other related co-morbidity of Obesity diseases*
Gallbladder Disease includes inflammation, infection, stones, or obstruction of the gallbladder.

Heartburn is a painful burning sensation in the esophagus, just below the breastbone. The pain often rises in your chest and may radiate to your neck or throat.

Heart disease is any disorder that affects the heart's ability to function normally. The most common cause of heart disease is narrowing or blockage of the coronary arteries, which supply blood to the heart Osteoarthritis is a chronic disease causing deterioration of the joint cartilage (the softer parts of bones which cushion their connections to each other) and the formation of new bone (bone spurs) at the margins of the joints.

Psychological Depression may be described as feeling sad, blue, unhappy, miserable, or down in the dumps. Most of us feel this way at one time or another for short periods. True clinical depression is a mood disorder in which feelings of sadness, loss, anger, or frustration interfere with everyday life for an extended time.

Sleep apnea is a condition characterized by episodes of stopped breathing during sleep. 

Stroke occurs when a blood vessel (artery) that supplies blood to the brain bursts or is blocked by a blood clot. Within minutes, the nerve cells in that area of the brain are damaged, and they may die within a few hours. As a result, the part of the body controlled by the damaged section of the brain cannot function properly.