A Normal BMI Doesn’t Mean You’re Healthy

You’ve probably heard about BMI (body mass index) and may even have used AICR’s calculator to learn what your BMI is.

BMI is based on a height and weight formula and is one simple way to estimate how much body fat you have. That’s important to know because too much body fat increases risk for many common cancers, type 2 diabetes and heart disease.

But a recent article in Science, suggests that almost one of ten Americans may have a normal BMI and still be at risk for chronic diseases typically lined to obesity.

BMI is a strong predictor of health risk in population studies, and obesity clearly increases risk for seven types of cancers and other chronic diseases. However, on an individual basis, the picture is more complex and depends on your metabolic health.

You may have a normal BMI – below 25 – but still have too much body fat and not enough muscle. And if that fat is primarily around your waist and deep inside your abdomen (apple shape), that fat – called visceral fat – is more metabolically active than fat around your hips or thighs (pear shape). It can create an unhealthy metabolic environment in your body.

That means you may have conditions like insulin resistance, reduced fitness, diabetes or glucose intolerance, chronic inflammation and muscle loss.

So how do you know if you are metabolically healthy? Right now there aren’t simple ways to measure levels of metabolic health. But blood sugar, cholesterol levels and waist size are a few indicators.

Regardless of your weight, if blood pressure is climbing or if your doctor says your blood sugar is borderline high or pre-diabetic, you are metabolically unhealthy. A waist size above the recommended levels may also mean poor metabolic health. You can often reverse these conditions through diet and activity changes. You may need more vegetables, fruit, beans and whole grains and fewer sugary drinks, high fat meats and other sweets on your plate.

Just as important is getting moving. Keep track of how active you are and how much you sit, then begin to increase your steps and find other ways to move so you are getting at least 30 minutes of moderate physical activity every day.

If your measures are in the healthy range, you can work to stay metabolically healthy throughout life:

1. Know your weight and monitor changes over time. Depending upon your goals, that may mean weighing  yourself every week or every month. If you see it creeping up, take steps to stop the slow gain that can really add up over time.
2. Measure your waist and monitor that over time too. If you notice your belt getting tighter, work on being more active every day. Learn how to measure your waist here.
3. Follow the New American Plate way of eating and pay attention to portion sizes to keep your weight stable.
4. Find ways to be physically active that you enjoy and that you can continue to do throughout life. But mix it up too – doing moderate aerobic activities, plus some resistance training and balance exercises will keep you fit.

Read more about metabolic health and obesity here.