Anybody who has been to Rainier Medical is all-too-familiar with the InBody analysis! Stepping on the machine every week or month is a rite of passage and is consistently reported as an integral part of the accountability which makes the program so successful. Why is it so much better than just the scale? Well, let’s see what information we can get from the InBody that we can not get from a simple scale and how that information potentially translates into important health prognosis. Is it a window into your future health?
Pull out your latest InBody sheet and let’s go through the components, what they mean, and how I use them in a prescriptive fashion for a program. This is how I interpret a scan for a patient:
Reference ranges: The report contains three categories for most variables measured. The “normal” range is represented by the hyphen (-), the range above normal has the arrow pointing up and the range below normal has the arrow pointing down. They also show both absolute numbers in pounds and percentiles for many readings. The percentile is shown as a percentage and is the percent of normal. For example, a trunk fat result showing 40 pounds and 300% means there is 40 pounds of fat in the trunk and that is 300% of normal. Take these ranges with the caveat that they are not adjusted for age or genetics, and it is expected that these may affect a person’s result. So, use them for reference but not absolute cutoffs, and focus more on brining your levels closer to the reference ranges, but it is not expected that they will necessarily go to the “normal” range. Most health benefits come from improvement.
Body Weight: This is the number you get on a scale. As you can see, it is a very small part of the InBody report. That is part of the reason that your body weight is just a number, and when you step on the scale in the morning, you need to remember there is so much more that goes into that number that is not shown on the scale! You are stepping on your home simple scale only for an estimate of what is going on and just to get a trend or one piece of data on a scatterplot. For the simple body weight to be meaningful, you need many data points over time.
Total Body Water: this is a large percentage of the total body weight, so you can see why your weight on the scale may fluctuate 3-5 pounds overnight in situations like dietary indiscretion, alcohol intake, hormone changes (menstrual cycle), airplane flights, or swelling due to increased exercise, or changes related to diuretic medication changes. The total body water tends to decrease about 3 pounds when a person transitions from a typical American diet to a diet that is low in processed foods and even more when on the Rainier Medical program. A reduction in excess water may be a marker of a “healthier” diet and may be associated in a reduction in systemic blood pressure and may reduce the workload on the cardiovascular system. After all, what has been the most common medication used to treat chronic hypertension which has shown reduced cardiovascular mortality: a diuretic, which reduces intravascular volume. So, which would you rather do: take a diuretic which can cause gout, osteoporosis, increased blood sugar, electrolyte abnormalities, or leg cramps, or change your diet? I know your answer to that question or you would not be reading this blog! This is part of the reason many people reduce or eliminate their need for blood pressure medication.
Total Body Fat Mass: This it the total pounds of fat in the body. Remember, it is normal, and imperative, to have body fat. This is the number to look at to see how many pounds of fat you are losing with a program, since it does not include changes in body water of muscle mass. But, not all fat is created equally, which is why we look further.
Visceral Fat: This tells you what KIND of fat you have. It is is a reflection of the amount of fat that is in the viscera, or solid organs, such as the liver, kidneys and heart. Fat can be either visceral or subcutaneous. Subcutaneous fat is under the skin but outside the abdominal cavity. Why does it matter? Well, visceral fat is the “sick fat” that is related to chronic diseases such as abnormal cholesterol, blood sugar, and fatty liver, and therefore is related to cardiovascular disease, which is the most common cause of death in the United States. It is also likely related to non-alcoholic fatty liver, which is the second leading cause of cirrhosis in the USA. Subcutaneous fat is less likely to make you “sick”, although it still can lead to mass related symptoms, such as joint pain, sleep apnea or shortness of breath with exertion. The normal range on an InBody is 7-10. Visceral fat levels may also reflect when someone is exercising or not. As someone exercises, the metabolic dysfunction of fat cells is improved, independent of weight loss. Have you ever exercised but not lost weight? Well, if you had measured your InBody, you likely would have seen an improvement in the visceral fat level. This is a reflection of the fact that exercise prevents disease even if it does not cause weight loss. We have learned from previous blogs that exercise as a primary means of weight loss has not been shown to be effective. But, it does prevent disease and weight regain. There are other ways to predict your health risk from you body composition analysis, so let’s keep moving.
Segmental Fat Analysis: This tells you WHERE the fat is. The major distinction is upper body versus lower body fat. Upper body fat is more likely to be associated with chronic metabolic diseases such as Type 2 Diabetes Mellitus, dylipidemia and cardiovascular disease. You may think that visceral fat and upper body fat are two ways of measuring the same thing, and there is significant cross-over, but it is not 100%. To read this part of the report, look at the trunk fat first. This is the amount of fat in the trunk. This is the number most closely predictive of metabolic disease, including insulin resistance and the risk of Type 2 Diabetes. The arm fat is also a component of upper body fat. The absolute numbers are much smaller than the trunk fat number, but the percentiles may be similar. If you are an “apple shape” the top 3 bars will be longer than the bottom two. If you have a “pear shape” the bottom two bars (lower body fat) will be longer. If you carry your weight distributed evenly all over your body, the 5 bars will be similar lengths. Sometimes, at higher body weights, a person who previously had even bars will develop excess upper body weight as well. This is the point at which metabolic syndrome can develop. If the top 3 bars are longer than the bottom 2, you are more at risk for metabolic complications from excess weight. If the bottom 2 are longer, you are more at risk for osteoarthritis and obstructive sleep apnea. If all 5 are even, your risk is somewhere in between.
Skeletal Muscle Mass: this is the total number of skeletal muscle mass in pounds. Many people now are astute enough to know that losing muscle can be “bad,” but it can also be “good”. Especially for this number, look at the percentile. The reference range on these is too low for the typical population. Probably, ideal is around 120%, in my opinion. However, if you know that you are “small boned”, then 100% may be “normal” for you. If you are up in the 130% range, then there is likely some risk of health complication from this excess weight, also, even though it is muscle. After all, a pound is a pound when it is on a joint or preventing diaphragm excursion while trying to breathe at night. In fact, one pound on your trunk is 4 pounds of force on your knee, because the knee has a smaller surface area. Remember how you can lie on a bed of nails but not step on a nail? That is because pressure is force per unit area, and high pressure on knees can cause degenerative osteoarthritis. So, it is expected that 10 to 20% of weight loss may be skeletal muscle mass. Not all muscle loss is bad, look at your percentile and at the next component on the report:
Segmental Lean Analysis: This tells you WHERE the skeletal muscle mass is, similar to the segmental fat analysis for the total body fat. Remember how we worried about trunk fat being related to adverse health outcomes? Well, the same may be true for excess muscle in the trunk. This is because excess trunk muscle is likely related to a state of high insulin levels. Insulin is anabolic, or promotes growth, in the trunk area, and this is true of both muscle and fat. The muscle in the trunk is probably not from exercise, it is probably from a high insulin state. So, I look for excess trunk muscle to decrease, while lower body muscle is optimized. The goal is to reduce the abdominal circumference, as a high waist circumference is an independent risk factor for cardiovascular disease. What frequently happens when someone just significantly cuts calories and does aerobic exercise is that lower body skeletal muscle mass as they “run off” their leg muscles. I see this also with some of the popular high intensity programs that include prolonged high intensity cycling or follow heart rate training and promote getting as many points as possible during a specified period of time. This is an example of when your weight may be going down, but it likely includes loss of lower body skeletal muscle mass. This is important because skeletal muscle expresses insulin receptors and causes insulin sensitization which prevents metabolic syndrome and Type 2 Diabetes.
Percent Body Fat: This is probably the second most important number to follow after total body weight. It shows the percentage of your body that is fat. This can be high even if your BMI is normal, which is the case in “normal weight obesity” which is most common in young adults and menopausal women. I also see a higher body fat percentage compared to BMI more often if someone has weight cycled often, especially under certain conditions such as catabolic anti obesity medications (i.e. phentermine) or high volume exercise (marathons), or history of orthopedic injuries or medications that cause weight gain. Keep in mind, at first, the percent body fat may change less than the total body weight due to initial water and muscle loss. During maintenance, I think a rise in body fat percentage precedes and predicts weight regain, which is why following the InBody even in maintenance is important. Why does this happen? Well, people tend to focus on calorie management and weight management rather than being on a specific program with medical foods. The former is much harder and more complicated than the latter!
There is one last rule when looking at your InBody: never compare your InBody to someone else's. Only compare yours to one of your own prior reports. As you look at them, you will see that each one tells a little story. This is my InBody that tells the story of Covid and the closed gyms. My weight is down in pounds, but the percent body fat is up. The peripheral fat percentile is below normal, but the trunk fat percentile is above normal. What is the story? Well, the gyms closed and I was under stress! Seeing the composition tells me what I already knew, but it gives me a better way to set a SMARTT goal and check on my progress. I will recheck it in a few weeks and see how things are working!
To properly prepare for your next body composition analysis, do not exercise, drink coffee, or alcohol for 8 hours before the test. Maintain a normal hydration status. Rainier Medical also offers the iHealth body composition scale for home monitoring which connects via bluetooth to the HealthTrac app used for remote patient monitoring, so you can do a virtual program.
I hope this blog shows you just a window into why weight management is so much more complex than calories in and calories out. My goal is to show you how you can measure objectively over time how your body is changing. Your program and approach can fluctuate based on the results. The body composition can help explain why people have different metabolisms and different health problems for a given body weight or BMI. The InBody results may predict the incidence of current or future health problems. Too often, I think people look only at the scale and them jump from one program to another if it is not going down fast enough, trying different things because the thing they did last time or used to work, no longer does. Remember, human physiology has not changed, so why are there “new” diets?
Take Back Your Health,
Valerie Sutherland, MD