Body fat and health: The true meaning of weight loss

Health tracking method

Fat content and health

By now, you should understand the true meaning of weight loss: the better your health, the lower your body fat percentage will be. Therefore, you need to learn some measurement methods to check your body fat percentage (fat mass) and overall health (health level).

Don't think this problem is simple; you can just step on the scale and find out the answer. I bet when you buy a steak, you don't buy the smallest piece just because it might have the least fat, right? However, most people who stand on the scale have this mindset: when they lose weight, they assume it's because they've lost fat, without considering that it could also be water or muscle weight, not necessarily fat.

Rose and Angie were determined to lose weight. Rose used a strict diet and lost 9 kilograms in a month; Angie, on the other hand, combined aerobics, a planned diet, and light weight training, and only lost 3.6 kilograms after a month. On the surface, Rose seemed to have successfully lost weight, but who actually lost the fat? Analysis of body fat tests showed that Rose did indeed lose 4.5 kilograms of fat, 3 kilograms of water, and 1 kilogram of muscle. After a month, Rose found it difficult to lose any more weight because she had lost muscle, which is responsible for burning calories; however, Angie could still enjoy a normal diet without gaining weight because she had more muscle to burn excess calories.

A complete and correct weight management plan must include body fat testing, in addition

Health tests are equally important because these two measurements reflect information about all aspects of metabolism in the body. Health tests aren't just about how fast you can run or how much weight you can lift. However, men often mistakenly equate these physical abilities with health, thinking that having the strength to tear a phone book apart or being able to run 100 steps in 10 seconds means they're healthy. This is not the case; running too fast can even lead to heart failure!

"Health" actually encompasses the body's overall metabolic function. Testing each function individually would be not only time-consuming but also extremely expensive. In the article "Simple Health Testing Methods," we will introduce indirect testing methods because improving your metabolic function through various means will inevitably trigger other changes. I want to especially urge you not to ignore these testing methods just because they seem simple; on the contrary, you should actively practice and utilize them.

Learn the body fat testing method carefully and diligently measure your health. If you're still ignoring this section after reading this far, you're wasting your time and money. These two test values ​​will form the basis for evaluating the effectiveness of your weight management plan and will be a key reference for how to effectively implement it.

Body fat test

For about 10 years, I traveled to major cities across the United States and Canada with a portable testing bucket, conducting body composition tests on all sorts of people, including dentists, psychologists, weightlifting coaches, Mormons, marathon runners, and so on. I could roughly estimate the average body fat percentage for almost any group you could name. I rarely use the immersion test anymore, although many people have had it done, since almost any medium-sized city has at least one testing center. Now, when I give presentations on body fat analysis, I mostly use the skin test. This method isn't perfectly accurate, but it allows me to perform more tests in a shorter time, and the results are quite accurate.

If body fat accounts for 20% of body weight, in other words, the other 80% is the weight of lean tissue, body fat tests cannot show where that 20% of fat is mainly located-though women probably already know this themselves. Furthermore, it won't tell you the proportions of water, bone, and muscle within the 80% lean tissue. When your weight fluctuates, body fat tests can indicate whether the increase or decrease is due to fat or lean tissue. However, it cannot tell you exactly where the change is occurring. Additionally, if weight loss is due to a decrease in lean tissue, this test cannot distinguish whether it's caused by dehydration, muscle atrophy, bone mineral loss, or disease. In sophisticated laboratories, CAT scans and neutron cloth analysis are commonly used to analyze areas of fat concentration. Furthermore, since these methods can also measure protein and calcium content, the muscle-to-bone ratio can be estimated. However, these tests are expensive and not affordable for the average person.

The following introduces some common testing methods.

Skin diameter measurement method

The principle of the skin diameter measurement method is to use skin wrinkles to measure the thickness of subcutaneous fat with a measuring instrument, and then estimate the total body fat mass. The average error of this method is approximately ±3% to 4%. That is, if a person's measurement value is 15%, the correct value should be between 11% and 19%. The average accuracy of the underwater immersion method is also approximately ±3% to 4%. Therefore, the skin diameter measurement method is an effective measurement method. Its only drawback is that it can only measure subcutaneous fat mass, unlike the underwater immersion method which can measure the proportion of body fat. The skin diameter measurement method is based on the assumption that "subcutaneous fat mass fully reflects total body fat mass." While this assumption is generally correct, there are exceptions for healthy athletes, thin individuals, or sedentary office workers. Typically, for trained athletes, the skin diameter measurement method tends to overestimate their body fat mass, by about 5% to 10% compared to the underwater immersion method. For those who do not exercise regularly, the body fat value measured by the skin diameter measurement method will be lower than that measured by the underwater immersion method.

Resistance measurement method

The principle of electrical resistance measurement is to measure the resistance of the human body to an electric current. Since current can easily pass through lean tissue but not easily through fat, a higher resistance value indicates more fat. Like the skin diameter measurement, electrical resistance measurement does not require the subject to perform any actions during the test. In its initial stages, electrical resistance measurement encountered considerable difficulties; different instruments often yielded different results, and even the same instrument testing the same person showed significant variations in values. These problems were finally resolved in 1988, and the average error of electrical resistance measurement was reduced to only 3% to 4%, the same as the skin diameter measurement. Nevertheless, I still recommend the skin diameter measurement, partly because it is more familiar, and partly because it saves the $5,000 cost of the instrument.

Ultrasonic method

The principle of ultrasound is to send ultrasound waves through the skin and fat. When it encounters denser, fat-free tissue, the waves bounce back, and the instrument picks up the information. Essentially, this method is the same as skin diameter measurement, so their measurement results, average errors, and the problems they face are largely the same. The major difference lies in the fact that the information from ultrasound is processed by a computer and then printed out in a very sophisticated manner. This processing makes ultrasound seem much more scientific.