Is it Possible to be Fit and Fat?

A: The short answer is yes — it's possible for you to be both fit and overweight, even obese. What’s really important to understand is what “fit” means and what “overweight” means relative to your health. The latter is typically defined by body mass index (BMI), a common measurement of body fat based on height and weight. According to World Health Organization, people with a BMI of 30 or more are considered obese, which puts them at risk for certain health problems. Those with a BMI below 25 are considered normal and healthy, while a BMI between 25 and 30 is defined as overweight.

The problem is, BMI doesn’t tell the whole story about someone’s health. For instance, the computation fails to take into account gender (women have more fat than men) or lean muscle mass. BMI also doesn’t measure how much fat you’re carrying compared to other components of the body — what’s called body composition, or the amount of lean tissue (muscle, bone and organs) and fat you have. “Two people with the same BMI can look very different,” says Stephen Brewer, M.D., medical director at Canyon Ranch in Tucson.

“Someone can have excess fat and have the same BMI as a person who has a lot of muscle.” Unfortunately, it’s not simple to measure body fat precisely, but using calipers, a tool that pinches skin folds to measure fat, is a useful estimate (note: calipers are more accurate if your body weight is within 20 pounds of a healthy weight). And BMI, along with an overall general medical review, can be a good starting point for flagging an increased risk for conditions that are linked to weight, like type 2 diabetes.

Fitness is also not so simple to define, but it typically means that you’re able to show aerobic fitness (meaning your heart and lungs can efficiently deliver blood to the muscles); muscle strength and endurance to do normal activities; and flexibility to move your joints. Fitness is the body’s ability to take in and use the oxygen you take in.

Studies show that when it comes to optimal health, it’s better to be overweight and aerobically active than thin and sedentary.

Here are a few other factors to consider when sizing up your health risks (especially those related to your heart) relative to weight and physical fitness:

Cholesterol and Blood Pressure

If these are normal, odds are you’re at low risk for some of the biggest health problems down the road. Results of one study showed that an unhealthy metabolic state — which includes hypertension, diabetes and/or high cholesterol — was consistently linked to an increased risk of dying or having heart problems, regardless of BMI. Check with your doctor to see how your metabolic stats measure up.

Workouts

Cardio activity improves how well your heart, lungs, bones and muscles work, not to mention the efficiency with which your body processes oxygen. It’s important to add cardio workouts to boost heart and lung function, but don’t skip the strength training, since weights build bones and muscle. For a more precise fitness assessment, ask an exercise physiologist. Your doctor can give you a stress test — where blood pressure and oxygen levels are measured while you walk or jog on a treadmill — to determine your cardiac risk.

Carrying Weight Around Your Middle

A bigger waist is likely to mean you have unhealthy amounts of visceral, or abdominal, fat, which can boost LDL (bad) cholesterol, increase blood pressure, increase insulin resistance, increase the potential for blood clotting and elevated a person's inflammatory markers— all of which does no favors for your heart.

The bottom line is that muscle mass and aerobic fitness are key. Abdominal weight does not affect all people the same way, so it is important to look at your health and opportunities to improve it with your doctor.

This article was originally published on November 6, 2021, and has been updated as of the above date.