Here is a wake-up call to everyone who thinks that risk for disease and early death is determined by weight and BMI alone. It’s not. The latest news is that you need to pay attention to your waist size, as well.

The new rule is that it’s not how much fat you carry; it’s where that fat is distributed. Said simply, it isn’t just how fat you are; it’s where the fat is that counts. A new studyby Mayo Clinic researchers revealed that normal-weight men and women who have a higher than normal waist circumference are at substantially increased risk of death (78 percent higher for the men; 50 percent higher for the women) from cardiovascular disease compared to normal-weight folks with normal-range waist circumference. This new body shape category is referred to as normal weight-central obesity.

The bottom line is that we all need to start taking our belly size seriously.

Understanding Belly Fats

I’m a belly fat scientist. In my lab at the National Institutes of Health, we found that not all fat is created equal. Internal belly fat, called visceral fat, resides deep inside the abdomen underneath the abdominal muscle wall. This type of fat is necessary for life. It helps us to maintain a normal internal body temperature, it buffers our organs, and it’s a calorie-burning fuel tank, there to provide lifesaving energy in times of famine.

This intra-abdominal fat is different from the fat found elsewhere on the body, which is referred to as subcutaneous fat (found under the skin). While subcutaneous fat is yellow, less vascular, and more of just a valuable physical cushion and energy fuel tank, visceral fat is deeper, white, rich in blood vessels, metabolically active, and a potent influence not only on the integrity of blood vessels, but also on the body’s ability to manage glucose and insulin. Too much of it increases inflammation throughout the body, increasing the risk for heart disease, diabetes, and cancer.

So how does someone who is normal weight accumulate excess internal belly fat? There are several factors that increase the likelihood of expanding that fat deposit:

• Chronic elevations of stress hormone. Our laboratory found that people who were experiencing chronic toxic stress (associated with feelings of helplessness, hopelessness, and defeat) secreted higher than normal levels of cortisol. This continuous elevation of cortisol facilitated the deposit of visceral fat.
• Changing sex hormone levels and lifestyle choices. After the age of 40, men and women begin to experience gender-specific declines in sex hormones. Decreases in testosterone in men and estrogen in women, in combination with overeating and lack of exercise, enable extra calories to be stored as visceral fat.
• Alcohol consumption. The origin of the beer belly emerged from early research that alcohol, especially in excess, had a propensity to enable visceral fat storage because the liver preferentially burns the alcohol, not fat. Since drinking alcohol is so often associated with the consumption of fries, not kale, and because it’s so easy to overdo the 150 calories in a beer or a glass of wine, it’s no wonder that alcohol and girth control go hand in gut!
• Medical conditions. Diseases like Cushing’s syndrome (high levels of cortisol) in men and women and polycystic ovarian syndrome (high levels of testosterone) in women can cause significant depositions of visceral fat.

Minimizing Unhealthy Belly Fat

What can you do, then, to maximize your health and minimize your girth? Here are 4 key tips and tools for those I call “waist warriors”:

1. Measure your success. Grab a tape measure. Wrap it around the smallest part of your waist, usually just above the belly button, to find your waist circumference in inches. Women, you want that number to be below 35 inches; men, below 40 inches. Now let’s see what your waist-to-hip ratio (WHR) looks like. The new research noted that men and women who exceeded norms were at much more risk for heart disease and early death. This time, you’ll measure the widest part of your butt/hip area in inches. Next, you’ll divide your waist measurement by your hip measurement. To make it easy, the Centers for Disease Control has a nifty website where all you have to do is plug in your numbers and out pops your WHR. Women, you’re aiming for a number below 0.80; men, below 0.90. People with higher numbers, especially 1.0 and greater, are at increased risk of disease and death.

2. Look in the mirror. What’s your body shape? Women, are you shaped like an hourglass, pear, or apple? Standing in your undies and looking at yourself front and side is revealing. Whether you’re male or female, if you are normal weight but have a belly that is clearly protruding, you may be accumulating too much visceral fat. If you’re overweight or obese and apple-shaped, you’ve probably accumulated excess visceral fat.

3. Take the visceral fat test. Many people have excess subcutaneous fat around their bellies; they may also have extra skin if they’ve experienced weight loss. And then there’s the post-pregnancy jelly belly. Here’s a simple way to differentiate your subcutaneous from visceral belly fat. I created this test, and it’s featured in my book Fight Fat after Forty. Lie on your back on a flat surface like the floor. You’ll notice that any extra subcutaneous fat tends to fall to the sides. Gaze down at your belly in this position. Is it flat? Do you notice a hump there? Now place an index finger on top of your pelvic bone on either side. No matter how much subcutaneous fat you have, you can touch that bone. Next, tighten your abdominal muscle, and move your fingers toward the midline until they meet there. While doing so, did you feel a rise in the abdominal muscle, akin to feeling a pregnancy bump? If you did (and sometimes you can just see it), that’s visceral fat pushing the muscle up, and it means you have an excess amount of it. If you didn’t feel the rise and your fingers felt a flat muscle, then it’s probable that you do not have excess visceral fat.

4. Factor in obesity-related risks. We have been talking about normal-weight people with expanded girths. However, if you’re an overweight or obese woman with a normal WHR, you are still at risk for problems related to excess fat throughout the body, such as breast cancer. Further, the majority of obese men and women are at greater risk for a spectrum of cancers, including colon cancer, as well as heart disease, hypertension, and diabetes. Also, there are physical disabilities that ensue when someone carries too much body weight.

So, no one is off the hook. We each have to be mindful to make the right daily healthy lifestyle choices to decrease our disease risk and optimize our life and health spans. The next time you find yourself racing over to the scale to monitor your weekly weight, you might want to grab your tape measure, too.