Diabetes is caused by abnormal levels of glucose in the blood. This can be the result of diet or genetics, however some are at a greater risk than others. For example, communities of color experience diabetes in higher rates.
The causes for heart disease vary from birth defect to diet. An unhealthy diet that would result in heart disease is one high in cholesterol, which coats the arteries and causes high blood pressure. Medication can be prescribed to ease chest pain, but only surgery can fix the problem.
Cancer is the uncontrolled growth of cells in the body. It can be caused by drug abuse, diet, and sexual reproductive behavior. In order to avoid it, one should eat fruits and vegetables as well as exercise regularly.