“Am I going to get diabetes—like my father—and die of a heart attack?” asked my patient, a 53-year-old high school math teacher. “I’ve looked this up online, and the outlook isn’t good.”

He was referring to the metabolic syndrome, a diagnosis made a week earlier after a physical exam showed he was overweight (with a waistline well over 40 inches) and hypertensive (with a systolic blood pressure over 160 and a diastolic over 90). When his lab results came back, I knew we were dealing with a serious situation. His serum triglycerides (a blood fat) were extremely high and his “good” HDL cholesterol very low—an ominous combination. On top of that, his fasting blood sugar was in the pre-diabetes range.

That combination of signs and symptoms, if left untreated, could result in a considerably shortened life span. Almost a third of American adults now have the metabolic syndrome, research suggests, though most don’t realize it.

The Dangers of Belly Fat

The metabolic syndrome is a combination of risk factors for type 2 diabetes, coronary heart disease, and stroke. Although definitions vary on the precise mix of signs and symptoms that make up the syndrome, my patient had what I think are the most characteristic.

Most notable: abdominal obesity, or a waist circumference of at least 40 inches in men and 35 inches in women. That’s worrisome, because abdominal fat is more metabolically active than fat in the rest of the body, which means it’s more likely to cause heart attacks and strokes.

In addition, that type of fat is associated with resistance to the blood-sugar-­lowering action of insulin, the hormone responsible for escorting glucose from our blood into our cells, where it is used as fuel for energy. In fact, a former name for the metabolic syndrome was insulin resistance, and the condition is often a prelude to type 2 diabetes.

The specs for the remaining components of the syndrome include triglycerides over 150 mg/dl, HDL cholesterol less than 40 mg/dl in men and 50 in women, blood pressure levels over 135 and 85, and a fasting blood sugar over 100 mg/dl.

How Metabolic Syndrome Can Harm You

My patient had all five warning signs, and as a math teacher, he knew how that multiplied his risks. In one meta-analysis, his chances for developing type 2 diabetes were up to more than five times the normal rate, and his risk for cardiovascular disease was doubled. People with the syndrome face an increased chance of other health problems, ranging from gout and sleep apnea to fatty liver disease, kidney failure, polycystic ovary disease, and even liver cancer.

Overall, his chance of dying prematurely was about 150 percent higher than someone without metabolic syndrome.

Dealing With Metabolic Syndrome

Some risk factors for the metabolic syndrome are not something you can control. For example, the syndrome is more common among women, African-Americans, Hispanics, Asians, and Native Americans. But there are a number of steps you can take, and my patient knew what he had to do before I told him.

We discussed diet. He decided to switch to a Mediterranean-style eating plan (high in nuts, whole grains, fruits and veggies, olive oil, and fish). In one study this popular—and tasty—diet resulted in greater weight loss and improvement in insulin resistance and blood lipids compared with a control diet. He decided to cut out pasta, rice, and potatoes, and restricted breads to whole-wheat versions. He limited his alcohol intake to one glass of wine per day. In addition (after a normal exercise stress test), he took advantage of a gym in the high school where he taught. Each morning prior to classes he undertook a 45-minute workout, alternating aerobics with strength training.

In the course of one year, he lost 15 percent of his body weight and brought his blood sugar, triglycerides, and HDL cholesterol levels back to normal. His new waistline now measures 39 inches, down from 44, and his blood pressure is under control, thanks in part to the blood pressure drug he now takes every day.

And he has kept his enthusiasm for his new exercise and diet regimen—especially since he learned that he was about to become a grandfather.