Metabolic syndrome  a group of risk factors linked to overweight and obesity that increase your probability for heart disease and other health problems such as diabetes and stroke. The term “metabolic” refers to the biochemical processes involved in the body’s normal functioning. Risk factors are behaviors or conditions that greatly increase your chance of getting a disease. In this article, “heart disease” refers to coronary heart disease.

The 5 conditions presented below are metabolic risk factors for coronary heart disease. A person can easily develop any one of these risk factors by itself, but they tend to happen together. Metabolic syndrome is diagnosed when a person has at least three of these dreaded heart disease risk factors:

• A larger waistline. This is also called abdominal obesity or “having an apple shape.” Excess fat in the abdominal area is a greater risk factor for heart disease than excess fat in other parts of the body, such as on the hips.
• A high triglyceride level in the blood (or you’re on medicine to treat high triglycerides). Triglycerides are a  fat  in the blood.
• A low level of HDL cholesterol (high-density lipoprotein cholesterol) in the blood (or you’re on medicine to treat low HDL). HDL is considered “good” cholesterol because it lessens your chances of heart disease. Low levels of HDL increase your chances of heart disease.
• Above normal blood pressure (or you’re on medicine to treat high blood pressure). Your blood pressure is recorded as two numbers, usually written one on top of or before the other, such as 120/80. The top or first number, called the systolic blood pressure, measures the pressure in the bloodstream when your ticker beats. The bottom or second number, called the diastolic blood pressure, measures the pressure in your blood stream between heart beats when the heart is in a relaxed state.
• High normal fasting blood sugar (glucose) (or you’re on medicine to treat high blood sugar). Even mildly high blood sugar can be an early warning sign of diabetes.

The more of these risk factors you have, the larger your chance of developing heart disease, diabetes, and stroke. In general, a person with metabolic syndrome is twice as likely to develop heart disease and five times as likely to develop diabetes as someone without Metabolic Syndrome.

Other risk factors aside from those of the metabolic syndrome also increase your risk for heart disease. A high level of LDL cholesterol (low-density lipoprotein cholesterol; considered “bad” cholesterol) and smoking, for example, are key risk factors for heart disease, but they aren’t components of metabolic syndrome. Even a single risk factor raises your risk for heart disease, and every risk factor should be lowered to reduce the risk.

The chance of developing metabolic syndrome is closely linked to being overweight or obese and to a lack of physical activity. Another cause is insulin resistance. Insulin resistance is a condition in which the body can’t use its insulin properly, efficiently. Insulin is a hormone the body uses to help convert blood sugar into energy. Insulin resistance can lead to high blood sugar levels and is closely linked with being overweight or obese.

Genetics (ethnicity and family history) and advanced age are other important underlying causes of metabolic syndrome.

For more try wikipedia on Metabolic Syndrome.