Health Risks: What Having a Bigger Belly Means

Take a look at your belly. How big is it? Is it round or flat? Hard or soft? The answers to these questions can provide clues about the likelihood of you developing certain conditions such as out-of-whack cholesterol, diabetes or heart disease.

Doctors look for markers that can give an indication of the state of your health. Blood samples, for instance, can be tested for a wide variety of enzymes and different cell counts to assess vitamin deficiencies, liver and immune functioning, and a diabetic’s glucose control.

Not all health indicators need to be measured in a medical lab, though. For example, hair loss, easy bruising and acne can all be observed by a doctor, and can be signs that the body is in a state of poor health. Fat, as it turns out, can also reflect the body’s health status—and abdominal fat, especially so.

Measuring Belly Fat

A high body mass index suggests that a person has greater amounts of body fat, but it doesn’t actually measure how much, or where it is in the body, so researchers interested in the effects of abdominal fat look for other ways to measure it. The most accurate ways to measure the amounts and types of fat within the belly are to use medical scanning laboratory equipment such as MRIs (magnetic resonance imaging) or CTs (computed tomography). This isn’t practical for most people and can be very expensive, so a simpler method used to estimate the amount of ab fat is to measure the waistline circumference.

The more fat in the abdominal area, the bigger your waist size tends to be. And a larger waistline is an independent predictor of health risks over and above what BMI predicts.

Keep in mind that age and ethnicity may affect waist size, partly due to genetics and partly due to differing lifestyle behaviors. Abdominal fat tends to increase with age in both men and women. A 2003 study in the journal Obesity Research reported that blacks tend to have more upper body fat based on waist size.

Research has determined that the cut-off point where health risks significantly increase for certain diseases is at 40 inches (102 cm) for men and 35 inches (88 cm) for women. Whether you are classified as “overweight” or “obese” according to your BMI—or even if you’re in the “normal” range—a waist size at or above these points is associated with a higher risk for type 2 diabetes, abnormal cholesterol levels, high blood pressure and cardiovascular disease.

It’s unclear exactly why excess ab fat can negatively impact health. Fat cells in this area may release more fatty acids into the blood circulation which then affect insulin sensitivity, cholesterol levels and other processes related to diabetes, hypertension and cardiovascular disease.

Are You At Risk?

The bigger your belly is, the more at risk you are of developing these conditions, and the risk increases as your BMI increases. In other words, the more overweight you are, the more problematic it is to have a bigger waistline. The NIH’s National Heart, Lung and Blood Institute 2002 obesity guidelines recommend that anyone with a BMI of 25 to 34.9 should also factor in their waist circumference to identify their degree of risk. People with extreme obesity, or a BMI of 40 or above, are already considered to be at very high risk, so their waist size is not usually measured.

Here is how your health risks increase at different BMIs if your waist circumference is higher than 40 inches (102 cm) in men and 35 inches (88 cm) in women:

• If your BMI is in the 18.5 to 24.9 range, or “Normal,” then a larger waist that is near or greater than 40 inches for men and 35 inches for women can indicate that you are at “increased” risk.

• If your BMI is in the 25 to 29.9 range, or “Overweight,” then a larger waist (less than or equal to 40 inches for men and 35 inches for women) can indicate that you are at “increased” risk. Above these sizes, the risk is considered “high.”

• If your BMI is in the 30 to 34.9 range, or “Obese I,” then a larger waist (less than or equal to 40 inches for men and 35 inches for women) can indicate that you are at “high” risk. Above these sizes, the risk is considered “very high.”

• If your BMI is in the 35 to 39.9 range, or “Obese II,” then a larger waist (less than or equal to 40 inches for men and 35 inches for women) can indicate that you are at “very high” risk. Above these sizes, the risk is still considered “very high.”

• If your BMI is or in the 40+ range, or “Obese III,” then a larger waist (less than or equal to 40 inches for men and 35 inches for women) can indicate that you are at “extremely high” risk. Above these sizes, the risk is still considered “extremely high.”

Even if your BMI is in the normal range, a larger belly may indicate that you have increased health risks. Some people may be a normal weight but still be in the early stages of developing insulin resistance and abnormal cholesterol, for example. One 1999 study published in the journal Diabetes found that women who were categorized as normal weight but “metabolically obese” tended to have a body fat percentage greater than 30 percent and higher amounts of abdominal fat.

How To Interpret Risk Status

Having a higher BMI and/or waist size have been shown to increase health risks for certain diseases. The labels for health risks (“increased” and “high” or “very high”) are used by health care professionals to determine how aggressively to modify the risk factors.

If your waist measurement is in the increased or higher risk ranges, it's a good idea to improve your lifestyle behaviors to lower your waist size. If you have a high BMI, or if you have a low BMI along with risk factors such as high blood pressure or abnormal cholesterol, then your physician may recommend weight loss.

If you have a high BMI and a high waist measurement, along with a history of heart disease, diabetes or sleep apnea, you are considered to be at a higher risk. A doctor may prescribe new or modify existing medications to better manage—and hopefully reduce—some of the risk factors.

Weight loss is almost always recommended to help manage obesity-related health risk factors. Eating more nutritious foods and controlling portions, as well as increasing your overall daily physical activity and performing more cardiovascular exercise, such as walking more often, can help decrease abdominal fat and lead to weight loss.