There seem to be electronic devices that allow us to monitor almost every aspect of our bodily functions. From sleep quality, heart rhythm, blood oxygen levels and blood sugar levels to calorie intake and energy output, we no longer depend on doctor visits to monitor our health. And we can do the monitoring daily.
But it seems the health-device industry has overlooked an essential monitoring tool: one that measures the percentage of fat, muscle, and water in our bodies that determines our weight.
Given the national obsession with whether we’re overweight or obese, it’s odd that most of us have the only device for determining this, our scale. (Or trying on the clothes we’re wearing when we think we’ve gained weight.) Of course, scales are a reliable measure of changes in our weight and tell us what we weigh today, but we can always know the weight on the scale translate? a normal, overweight or obese status?
A standard for normal or obese status is the BMI, Body Mass Index. There are charts that BMI can be plugged into to see if our weight is in the normal or abnormal range (both too low and too high). BMI is determined by dividing your weight in pounds by your height in inches squared and then multiplying that number by 703.
But there are some obvious problems with relying solely on the scale and then BMI to judge “fat or thin.” Because BMI relates weight to height, shrinking height, as many do with age, can lead one to go from normal to overweight or obese. A medically approved weight for a person of 5 feet 10 inches may be overweight if the person is now 5 feet 7 inches tall. (I have a cartoon that shows a woman on stilts standing on a scale, and because she’s 5 inches taller now, she tells herself her BMI is normal.)
Muscle weight can also falsify the accuracy of the BMI. The scale does not differentiate between muscle, fat or water weight. Two people can be the same weight but have different body compositions; you’re heavily muscled and you have too many fat cells. A male friend found he lost weight when his treatment for prostate cancer depleted his body of testosterone. Much of the weight loss was due to muscle wasting, a side effect of his treatment.
However, methods of assessing body composition are not readily available to the layperson, with the exception of skin calipers, and even they require the expertise of someone trained to use them. The skin is pinched at several points on the body with calipers and the thickness (representing subcutaneous fat) is analyzed in a mathematical formula. Do-it-yourself skin thickness measurement is possible, but only after a lot of practice and supervision by someone who knows what to do.
Scales are available with an additional body composition measurement device that uses bioelectrical impedance. You stand up or grab electrodes, and tiny electrical impulses are sent through your body. Lean tissue conducts impulses faster than fat tissue, so impulses travel faster when the person is leaner. Again, there are formulas to convert the numbers into the relative amounts of fat and lean tissue.
But even here the measurement can be inaccurate. Hydration affects the reading because water conducts electrical impulses, so drinking water or sweating before taking the reading will change the results. Eating before the measurement influences the measurement, as does exercise.
If you have access to a swimming pool, hydrostatic weighing could be an option. After exhaling as much air as possible, sit underwater and your weight will be recorded while fully submerged. It is then compared to your weight on land. The two weights, with the right mathematical manipulations, show body density, and this in turn provides information on which body components contribute to body density. The only downside (apart from not enjoying holding your breath and sitting underwater) is that the method measures bone density, and bone density, which can be altered by movement or bone loss, affects the accuracy of the measurement . In addition, this method is unlikely to be widely used, for example to track the effects of a diet.
Dual-energy X-ray absorptiometry, also known as DEXA, is probably the most accurate way to measure body fat, but you can’t do it at home. You have to go to a special facility and lie down on a table while the machine’s arm runs over your body, emitting high- and low-energy X-rays. The rays are absorbed by the various body components and translated into measurements of bone, lean body mass and fat density.
The machine can provide surprising results. Years ago, when we were studying the eating habits of thin women in the first few weeks of smoking cessation, we used DEXA to study their body mass with their permission. To our surprise, the amount of fat in her body was somewhat similar to someone who is overweight or even obese. The scales recorded low weight because their muscle mass was low, not because they had low body fat.
DEXA measurements require an appointment at a clinic and a justification for the measurement to the health insurance company. Currently the COVID-related backlog of appointments means waiting for the approval and the appointment. This is clearly not an easily accessible method for determining changes in body composition associated with weight loss or gain.
So the question becomes, where is the new technology that will allow us to accurately measure our body composition at home? We should be able to figure out if our weight loss program is maintaining our muscle mass or if we’re losing weight because we’re losing both muscle and fat. We should be able to know if the treatment we are doing for bone loss will stop the loss and increase bone density. We need to know if the elderly member of our family is unable to get up from a chair or walk unaided due to muscle wasting. We need to know if our older teen’s weight is gaining because he has an intense exercise program or because he eats fast food every day after school.
Given the rapidity with which medical devices for home health care are being developed, it is hoped that an easy-to-use, accurate device will be available in the near future. Being able to track our own body composition changes accurately and often will have benefits beyond learning how quickly our fat mass is changing.