Metabolic syndrome is a group of conditions that put you at risk for heart disease and diabetes. These conditions are

• High blood pressure
• High blood glucose, or blood sugar, levels
• High levels of triglycerides, a type of fat, in your blood
• Low levels of HDL, the good cholesterol, in your blood
• Too much fat around your waist

Not all doctors agree on the definition or cause of metabolic syndrome. The cause might be insulin resistance. Insulin is a hormone your body produces to help you turn sugar from food into energy for your body. If you are insulin resistant, too much sugar builds up in your blood, setting the stage for disease.

NIH: National Institute of Diabetes and Digestive and Kidney Diseases